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Ünlü E, Çalış Ö, Say A, Karim AA, Yetişir H, Yılmaz S. Investigation of the effects of Bacillus subtilis and Bacillus thuringiensis as Bio-agents against powdery mildew (Podosphaera xanthii) disease in zucchini (Cucurbita pepo L.). Microb Pathog 2023; 185:106430. [PMID: 37940063 DOI: 10.1016/j.micpath.2023.106430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/23/2023] [Accepted: 10/28/2023] [Indexed: 11/10/2023]
Abstract
Fungi, bacteria, and viruses cause highly devastating diseases in species of the Cucurbitaceae family. Powdery mildew, a fungal disease, is one of the most important diseases of cucurbits. The pathogen, Podosphaera xanthii, is the most common causal agent of powdery mildew disease within cucurbits. The aim of this study was to investigate the effectiveness of the combined formulations of two biological agents, B. subtilis and B. thuringiensis, in combating powdery mildew disease, which represents a significant threat to C. pepo cultivation in Kayseri, Türkiye. The efficacy of six different treatments in controlling the disease agent P. xanthii was evaluated in susceptible zucchini genotypes. It was found that full-dose bacteria dilution application, before and after powdery mildew infection, as well as three- and five-fold bacteria dilutions application significantly prevented (1-2 scale value) powdery mildew disease on infected zucchini plants than the control application. There was a decrease in vegetative growth in the control-treated crops while plant growth increased significantly in bacterial-treated crops. Also, our findings showed that combined formulations made from Bacillus subtilis (61.29e and 3.3a strains) and Bacillus thuringiensis (2B3-1 and 2B2-2 strains) significantly increased the synthesis of plant defense enzymes such as DPPH, antioxidant, proline production, total phenolic substance, and total flavonoid content. The application of B + PM resulted in the highest enzyme contents, quantified as follows: 22.91 mg AAE/g antioxidant, 2.01 mg/g KU proline, 10.03 mg GAE/g TPC, and 7.756 mg CE/g TFC. These enzymes may have played vital roles in triggering zucchini defense mechanisms, thereby significantly preventing powdery disease in the bacteria-treated crops.
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Affiliation(s)
- Emel Ünlü
- Erciyes University, Faculty of Agriculture, Department of Horticulture, Kayseri, Turkey.
| | - Özer Çalış
- Akdeniz University, Faculty of Agriculture, Department of Phytopathology, Antalya, Turkey
| | - Ahmet Say
- Erciyes University, Faculty of Agriculture, Department of Agricultural Biotechnology, Kayseri, Turkey
| | - Abdul Aziz Karim
- Erciyes University, Faculty of Agriculture, Department of Agricultural Sciences and Technologies, Kayseri, Turkey
| | - Halit Yetişir
- Erciyes University, Faculty of Agriculture, Department of Horticulture, Kayseri, Turkey
| | - Semih Yılmaz
- Erciyes University, Faculty of Agriculture, Department of Agricultural Biotechnology, Kayseri, Turkey
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Olawole OI, Gleason ML, Beattie GA. Expression and Functional Analysis of the Type III Secretion System Effector Repertoire of the Xylem Pathogen Erwinia tracheiphila on Cucurbits. Mol Plant Microbe Interact 2022; 35:768-778. [PMID: 35471035 DOI: 10.1094/mpmi-01-22-0002-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The predicted repertoire of type III secretion system effectors (T3SEs) in Erwinia tracheiphila, causal agent of cucurbit bacterial wilt, is much larger than in xylem pathogens in the closely related genera Erwinia and Pantoea. The genomes of strains BHKY and SCR3, which represent distinct E. tracheiphila clades, encode at least 6 clade-specific and 12 shared T3SEs. The strains expressed the majority of the T3SE genes examined in planta. Among the shared T3SE genes, eop1 was expressed most highly in both strains in squash (Cucurbita pepo) and muskmelon (Cucumis melo) but the clade-specific gene avrRpm2 was expressed 40- to 900-fold more than eop1 in BHKY. The T3SEs AvrRpm2, Eop1, SrfC, and DspE contributed to BHKY virulence on squash and muskmelon, as shown using combinatorial mutants involving six T3SEs, whereas OspG and AvrB4 contributed to BHKY virulence only on muskmelon, demonstrating host-specific virulence functions. Moreover, Eop1 was functionally redundant with AvrRpm2, SrfC, OspG, and AvrB4 in BHKY, and BHKY mutants lacking up to five effector genes showed similar virulence to mutants lacking only two genes. The T3SEs OspG, AvrB4, and DspE contributed additively to SCR3 virulence on muskmelon and were not functionally redundant with Eop1. Rather, loss of eop1 and avrB4 restored wild-type virulence to the avrB4 mutant, suggesting that Eop1 suppresses a functionally redundant effector in SCR3. These results highlight functional differences in effector inventories between two E. tracheiphila clades, provide the first evidence of OspG as a phytopathogen effector, and suggest that Eop1 may be a metaeffector influencing virulence. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Olakunle I Olawole
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011-1101, U.S.A
| | - Mark L Gleason
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011-1101, U.S.A
| | - Gwyn A Beattie
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011-1101, U.S.A
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LaSarre B, Olawole OI, Paulsen AA, Halverson LJ, Gleason ML, Beattie GA. Complete Genome Sequences of Four Strains of Erwinia tracheiphila: A Resource for Studying a Bacterial Plant Pathogen with a Highly Complex Genome. Mol Plant Microbe Interact 2022; 35:500-504. [PMID: 35491948 DOI: 10.1094/mpmi-01-22-0008-a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Affiliation(s)
- Breah LaSarre
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011-1101, U.S.A
| | - Olakunle I Olawole
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011-1101, U.S.A
| | - Ashley A Paulsen
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011-1101, U.S.A
| | - Larry J Halverson
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011-1101, U.S.A
| | - Mark L Gleason
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011-1101, U.S.A
| | - Gwyn A Beattie
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011-1101, U.S.A
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Margaritopoulou T, Kizis D, Kotopoulis D, Papadakis IE, Anagnostopoulos C, Baira E, Termentzi A, Vichou AE, Leifert C, Markellou E. Enriched HeK4me3 marks at Pm-0 resistance-related genes prime courgette against Podosphaera xanthii. Plant Physiol 2022; 188:576-592. [PMID: 34597395 PMCID: PMC8774738 DOI: 10.1093/plphys/kiab453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Powdery mildew (PM) disease, caused by the obligate biotrophic fungal pathogen Podosphaera xanthii, is the most reported and destructive disease on cultivated Cucurbita species all over the world. Recently, the appearance of highly aggressive P. xanthii isolates has led to PM outbreaks even in resistant crops, making disease management a very difficult task. To challenge this, breeders rely on genetic characteristics for PM control. Analysis of commercially available intermediate resistance courgette (Cucurbita pepo L. var. cylindrica) varieties using cytological, molecular, and biochemical approaches showed that the plants were under a primed state and induced systemic acquired resistance (SAR) responses, exhibiting enhanced callose production, upregulation of salicylic acid (SA) defense signaling pathway genes, and accumulation of SA and defense metabolites. Additionally, the intermediate resistant varieties showed an altered epigenetic landscape in histone marks that affect transcriptional activation. We demonstrated that courgette plants had enriched H3K4me3 marks on SA-BINDING PROTEIN 2 and YODA (YDA) genes of the Pm-0 interval introgression, a genomic region that confers resistant to Cucurbits against P. xanthii. The open chromatin of SA-BINDING PROTEIN 2 and YDA genes was consistent with genes' differential expression, induced SA pathway, altered stomata characteristics, and activated SAR responses. These findings demonstrate that the altered epigenetic landscape of the intermediate resistant varieties modulates the activation of SA-BINDING PROTEIN 2 and YDA genes leading to induced gene transcription that primes courgette plants.
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Affiliation(s)
- Theoni Margaritopoulou
- Scientific Directorate of Phytopathology, Benaki Phytopathological Institute, Athens 14561, Greece
| | - Dimosthenis Kizis
- Scientific Directorate of Phytopathology, Benaki Phytopathological Institute, Athens 14561, Greece
| | - Dimitris Kotopoulis
- Scientific Directorate of Phytopathology, Benaki Phytopathological Institute, Athens 14561, Greece
| | - Ioannis E Papadakis
- Faculty of Crop Science, Agricultural University of Athens, Athens 11855, Greece
| | - Christos Anagnostopoulos
- Scientific Directorate of Pesticides' Assessment & Phytopharmacy, Benaki Phytopathological Institute, Athens 14561, Greece
| | - Eirini Baira
- Scientific Directorate of Pesticides' Assessment & Phytopharmacy, Benaki Phytopathological Institute, Athens 14561, Greece
| | - Aikaterini Termentzi
- Scientific Directorate of Pesticides' Assessment & Phytopharmacy, Benaki Phytopathological Institute, Athens 14561, Greece
| | - Aikaterini-Eleni Vichou
- Scientific Directorate of Phytopathology, Benaki Phytopathological Institute, Athens 14561, Greece
| | - Carlo Leifert
- SCU Plant Science, Southern Cross University, Lismore, Australia
- Department of Nutrition, IMB, University of Oslo, Oslo 0372, Norway
| | - Emilia Markellou
- Scientific Directorate of Phytopathology, Benaki Phytopathological Institute, Athens 14561, Greece
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Babu RG, C C. Different stages of disease detection in squash plant based on machine learning. J Biosci 2022; 47:9. [PMID: 35092411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
To increase agriculture production, accurate and fast detection of plant disease is required. Expert advice is needed to detect disease in plants, nutrition deficiencies or any other abnormalities caused by extreme weather conditions. But this process is very tedious, costly, and takes more time. In this paper, hyperspectral imaging and machine learning were used to detect different stages (early, middle, and critical stage) of the powderly mildew disease (PMD) in squash plants. An unmanned aerial vehicle (UAV) was used to collect the data from the field and Locality Preserving Discriminative Broad Learning (LPDBL) was used to distinguish the diseased and healthy plants. In addition, the ability to detect the diseased plant by the proposed method was evaluated using 10 different spectral vegetation indices (VIs). The results show the proposed method detected the disease accurately in the early, middle, and critical stages of the squash plant. The proposed method's performance is compared with six different PMDs under indoor laboratory test and UAV-based field test conditions. The comparison's results show that the LPDBL provides better accuracy in detecting disease in the squash plant.
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Affiliation(s)
- R Ganesh Babu
- Department of ECE, SRM TRP Engineering College, Tiruchirappalli, India
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Wang Y, Qi C, Luo Y, Zhang F, Dai Z, Li M, Qu S. Identification and mapping of CpPM10.1, a major gene involved in powdery mildew (race 2 France of Podosphaera xanthii) resistance in zucchini (Cucurbita pepo L.). Theor Appl Genet 2021; 134:2531-2545. [PMID: 33914112 DOI: 10.1007/s00122-021-03840-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/17/2021] [Indexed: 06/12/2023]
Abstract
Powdery mildew resistance in zucchini is controlled by one major dominant locus, CpPM10.1. CpPM10.1 was fine mapped. The expression of candidate gene Cp4.1LG10g02780 in resistant individuals was significantly upregulated after inoculation with the powdery mildew. Powdery mildew (PM) is one of the most destructive fungal diseases, reducing the productivity of Cucurbita crops globally. PM influences the photosynthesis, growth and development of infected zucchini and seriously reduces fruit yield and quality. In the present study, the zucchini inbred line 'X10' had highly stable PM resistance, and the inbred line 'Jin234' was highly susceptible to PM in the seedling stage and adult stages. Genetic analysis revealed that PM resistance in 'X10' is controlled by one major dominant locus. Based on the strategy of QTL-seq combined with linkage analysis and developed molecular markers, the major locus was found to be located in a 382.9-kb candidate region on chromosome 10; therefore, the major locus was named CpPM10.1. Using 1,400 F2 individuals derived from a cross between 'X10' and 'JIN234' and F2:3 offspring of the recombinants, the CpPM10.1 locus was defined in a region of approximately 20.9 kb that contained 5 coding genes. Among them, Cp4.1LG10g02780 contained a conserved domain (RPW8), which controls resistance to a broad range of PM pathogens. Cp4.1LG10g02780 also had nonsynonymous SNPs between the resistant 'X10' and susceptible 'Jin234.' Furthermore, the expression of Cp4.1LG10g02780 was strongly positively involved in PM resistance in the key period of inoculation. Further allelic diversity analysis in zucchini germplasm resources indicated that PM resistance was associated with two SNPs in the Cp4.1LG10g02780 RPW8 domain. This study not only provides highly stable PM resistance gene resources for cucurbit crops but also lays the foundation for the functional analysis of PM resistance and resistance breeding in zucchini.
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Affiliation(s)
- Yunli Wang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, 150030, China
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China
| | - Cong Qi
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, 150030, China
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China
| | - Yusong Luo
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, 150030, China
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China
| | - Feng Zhang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, 150030, China
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China
| | - Zuyun Dai
- Anhui Jianghuai Horticulture Seeds Corporation Limited, Hefei, 230031, China
| | - Man Li
- Anhui Jianghuai Horticulture Seeds Corporation Limited, Hefei, 230031, China
| | - Shuping Qu
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin, 150030, China.
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China.
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Polonio Á, Fernández‐Ortuño D, de Vicente A, Pérez‐García A. A haustorial-expressed lytic polysaccharide monooxygenase from the cucurbit powdery mildew pathogen Podosphaera xanthii contributes to the suppression of chitin-triggered immunity. Mol Plant Pathol 2021; 22:580-601. [PMID: 33742545 PMCID: PMC8035642 DOI: 10.1111/mpp.13045] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/04/2021] [Accepted: 02/04/2021] [Indexed: 05/06/2023]
Abstract
Podosphaera xanthii is the main causal agent of cucurbit powdery mildew and a limiting factor of crop productivity. The lifestyle of this fungus is determined by the development of specialized parasitic structures inside epidermal cells, termed haustoria, that are responsible for the acquisition of nutrients and the release of effectors. A typical function of fungal effectors is the manipulation of host immunity, for example the suppression of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). Chitin is a major component of fungal cell walls, and chitin oligosaccharides are well-known PAMP elicitors. In this work, we examined the role of PHEC27213, the most highly expressed, haustorium-specific effector candidate of P. xanthii. According to different computational predictions, the protein folding of PHEC27213 was similar to that of lytic polysaccharide monooxygenases (LPMOs) and included a conserved histidine brace; however, PHEC27213 had low sequence similarity with LPMO proteins and displayed a putative chitin-binding domain that was different from the canonical carbohydrate-binding module. Binding and enzymatic assays demonstrated that PHEC27213 was able to bind and catalyse colloidal chitin, as well as chitooligosaccharides, acting as an LPMO. Furthermore, RNAi silencing experiments showed the potential of this protein to prevent the activation of chitin-triggered immunity. Moreover, proteins with similar features were found in other haustorium-forming fungal pathogens. Our results suggest that this protein is a new fungal LPMO that catalyses chitooligosaccharides, thus contributing to the suppression of plant immunity during haustorium development. To our knowledge, this is the first mechanism identified in the haustorium to suppress chitin signalling.
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Affiliation(s)
- Álvaro Polonio
- Departamento de MicrobiologíaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’Universidad de MálagaConsejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC)MálagaSpain
| | - Dolores Fernández‐Ortuño
- Departamento de MicrobiologíaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’Universidad de MálagaConsejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC)MálagaSpain
| | - Antonio de Vicente
- Departamento de MicrobiologíaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’Universidad de MálagaConsejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC)MálagaSpain
| | - Alejandro Pérez‐García
- Departamento de MicrobiologíaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’Universidad de MálagaConsejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC)MálagaSpain
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Moumni M, Allagui MB, Mezrioui K, Ben Amara H, Romanazzi G. Evaluation of Seven Essential Oils as Seed Treatments against Seedborne Fungal Pathogens of Cucurbita maxima. Molecules 2021; 26:molecules26082354. [PMID: 33919567 PMCID: PMC8073776 DOI: 10.3390/molecules26082354] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/08/2021] [Accepted: 04/14/2021] [Indexed: 12/03/2022] Open
Abstract
Essential oils are gaining interest as environmentally friendly alternatives to synthetic fungicides for management of seedborne pathogens. Here, seven essential oils were initially tested in vivo for disinfection of squash seeds (Cucurbita maxima) naturally contaminated by Stagonosporopsis cucurbitacearum, Alternaria alternata, Fusarium fujikuro, Fusarium solani, Paramyrothecium roridum, Albifimbria verrucaria, Curvularia spicifera, and Rhizopus stolonifer. The seeds were treated with essential oils from Cymbopogon citratus, Lavandula dentata, Lavandula hybrida, Melaleuca alternifolia, Laurus nobilis, and Origanum majorana (#1 and #2). Incidence of S. cucurbitacearum was reduced, representing a range between 67.0% in L. nobilis to 84.4% in O. majorana #2. Treatments at 0.5 mg/mL essential oils did not affect seed germination, although radicles were shorter than controls, except with C. citratus and O. majorana #1 essential oils. Four days after seeding, seedling emergence was 20%, 30%, and 10% for control seeds and seeds treated with C. citratus essential oil (0.5 mg/mL) and fungicides (25 g/L difenoconazole plus 25 g/L fludioxonil). S. cucurbitacearum incidence was reduced by ~40% for plantlets from seeds treated with C. citratus essential oil. These data show the effectiveness of this essential oil to control the transmission of S. cucurbitacearum from seeds to plantlets, and thus define their potential use for seed decontamination in integrated pest management and organic agriculture.
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Affiliation(s)
- Marwa Moumni
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, 60131 Ancona, Italy; (M.M.); (K.M.)
- Laboratory of Plant Protection, National Institute for Agronomic Research of Tunisia, University of Carthage, 2080 Ariana, Tunisia; (M.B.A.); (H.B.A.)
| | - Mohamed Bechir Allagui
- Laboratory of Plant Protection, National Institute for Agronomic Research of Tunisia, University of Carthage, 2080 Ariana, Tunisia; (M.B.A.); (H.B.A.)
| | - Kaies Mezrioui
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, 60131 Ancona, Italy; (M.M.); (K.M.)
- Laboratory of Plant Protection, National Institute for Agronomic Research of Tunisia, University of Carthage, 2080 Ariana, Tunisia; (M.B.A.); (H.B.A.)
| | - Hajer Ben Amara
- Laboratory of Plant Protection, National Institute for Agronomic Research of Tunisia, University of Carthage, 2080 Ariana, Tunisia; (M.B.A.); (H.B.A.)
| | - Gianfranco Romanazzi
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, 60131 Ancona, Italy; (M.M.); (K.M.)
- Correspondence: ; Tel.: +39-071-2204336
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Vogel G, LaPlant KE, Mazourek M, Gore MA, Smart CD. A combined BSA-Seq and linkage mapping approach identifies genomic regions associated with Phytophthora root and crown rot resistance in squash. Theor Appl Genet 2021; 134:1015-1031. [PMID: 33388885 DOI: 10.1007/s00122-020-03747-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/05/2020] [Indexed: 06/12/2023]
Abstract
Two QTL mapping approaches were used to identify a total of six QTL associated with Phytophthora root and crown rot resistance in a biparental squash population. Phytophthora root and crown rot, caused by the soilborne oomycete pathogen Phytophthora capsici, leads to severe yield losses in squash (Cucurbita pepo). To identify quantitative trait loci (QTL) involved in resistance to this disease, we crossed a partially resistant squash breeding line with a susceptible zucchini cultivar and evaluated over 13,000 F2 seedlings in a greenhouse screen. Bulked segregant analysis with whole genome resequencing (BSA-Seq) resulted in the identification of five genomic regions-on chromosomes 4, 5, 8, 12, and 16-featuring significant allele frequency differentiation between susceptible and resistant bulks in each of two independent replicates. In addition, we conducted linkage mapping using a population of 176 F3 families derived from individually genotyped F2 individuals. Variation in disease severity among these families was best explained by a four-QTL model, comprising the same loci identified via BSA-Seq on chromosomes 4, 5, and 8 as well as an additional locus on chromosome 19, for a combined total of six QTL identified between both methods. Loci, whether those identified by BSA-Seq or linkage mapping, were of small-to-moderate effect, collectively accounting for 28-35% and individually for 2-10% of the phenotypic variance explained. However, a multiple linear regression model using one marker in each BSA-Seq QTL could predict F2:3 disease severity with only a slight drop in cross-validation accuracy compared to genomic prediction models using genome-wide markers. These results suggest that marker-assisted selection could be a suitable approach for improving Phytophthora crown and root rot resistance in squash.
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Affiliation(s)
- Gregory Vogel
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY, 14456, USA
| | - Kyle E LaPlant
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Michael Mazourek
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Michael A Gore
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Christine D Smart
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY, 14456, USA.
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Polonio Á, Díaz-Martínez L, Fernández-Ortuño D, de Vicente A, Romero D, López-Ruiz FJ, Pérez-García A. A Hybrid Genome Assembly Resource for Podosphaera xanthii, the Main Causal Agent of Powdery Mildew Disease in Cucurbits. Mol Plant Microbe Interact 2021; 34:319-324. [PMID: 33141618 DOI: 10.1094/mpmi-08-20-0237-a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Podosphaera xanthii is the main causal agent of powdery mildew in cucurbits and, arguably, the most important fungal pathogen of cucurbit crops. Here, we present the first reference genome assembly for P. xanthii. We performed a hybrid genome assembly, using reads from Illumina NextSeq550 and PacBio Sequel S3. The short and long reads were assembled into 1,727 scaffolds with an N50 size of 163,173 bp, resulting in a 142-Mb genome size. The combination of homology-based and ab initio predictions allowed the prediction of 14,911 complete genes. Repetitive sequences comprised 76.2% of the genome. Our P. xanthii genome assembly improves considerably the molecular resources for research on P. xanthii-cucurbit interactions and provides new opportunities for further genomics, transcriptomics, and evolutionary studies in powdery mildew fungi.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Álvaro Polonio
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
| | - Luis Díaz-Martínez
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
| | - Dolores Fernández-Ortuño
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
| | - Antonio de Vicente
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
| | - Diego Romero
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
| | - Francisco J López-Ruiz
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Perth, WA 6102, Australia
| | - Alejandro Pérez-García
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
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11
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Rocha J, Shapiro LR, Kolter R. A horizontally acquired expansin gene increases virulence of the emerging plant pathogen Erwinia tracheiphila. Sci Rep 2020; 10:21743. [PMID: 33303810 PMCID: PMC7729394 DOI: 10.1038/s41598-020-78157-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 11/09/2020] [Indexed: 12/16/2022] Open
Abstract
Erwinia tracheiphila is a bacterial plant pathogen that causes a fatal wilt infection in some cucurbit crop plants. Wilt symptoms are thought to be caused by systemic bacterial colonization through xylem that impedes sap flow. However, the genetic determinants of within-plant movement are unknown for this pathogen species. Here, we find that E. tracheiphila has horizontally acquired an operon with a microbial expansin (exlx) gene adjacent to a glycoside hydrolase family 5 (gh5) gene. Plant inoculation experiments with deletion mutants in the individual genes (Δexlx and Δgh5) and the full operon (Δexlx-gh5) resulted in decreased severity of wilt symptoms, decreased mortality rate, and impaired systemic colonization compared to the Wt strain. Co-inoculation experiments with Wt and Δexlx-gh5 rescued the movement defect of the mutant strain, suggesting that expansin and GH5 function extracellularly. Together, these results show that expansin-GH5 contributes to systemic movement through xylem, leading to rapid wilt symptom development and higher rates of plant death. The presence of expansin genes in diverse species of bacterial and fungal wilt-inducing pathogens suggests that microbial expansin proteins may be an under-appreciated virulence factor for many pathogen species.
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Affiliation(s)
- Jorge Rocha
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
- Conacyt-Centro de Investigación y Desarrollo en Agrobiotecnología Alimentaria, San Agustin Tlaxiaca, 42163, Hidalgo, Mexico.
| | - Lori R Shapiro
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Roberto Kolter
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
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12
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Zhao Q, Wu J, Zhang L, Yan C, Jiang S, Li Z, Sun D, Lai Y, Gong Z. Genome-scale analyses and characteristics of putative pathogenicity genes of Stagonosporopsis cucurbitacearum, a pumpkin gummy stem blight fungus. Sci Rep 2020; 10:18065. [PMID: 33093634 PMCID: PMC7581720 DOI: 10.1038/s41598-020-75235-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 10/12/2020] [Indexed: 11/13/2022] Open
Abstract
Outbreaks of gummy stem blight (GSB), an emerging seed pumpkin disease, have increased in number and have become more widespread in recent years. Previously we reported that Stagonosporopsis cucurbitacearum (Sc.) is the dominant fungal cause of pumpkin seedling GSB in Northeast China, where it has greatly reduced crop yields in that region. Here, high-throughput whole-genome sequencing and assembly of the Sc. genome were conducted toward revealing pathogenic molecular regulatory mechanisms involved in fungal growth and development. Zq-1 as representative Sc. strain, DNA of Zq-1was prepared for genomic sequencing, we obtained 5.24 Gb of high-quality genomic sequence data via PacBio RS II sequencing. After sequence data was processed to filter out low quality reads, a hierarchical genome-assembly process was employed that generated a genome sequence of 35.28 Mb in size. A total of 9844 genes were predicted, including 237 non-coding RNAs, 1024 genes encoding proteins with signal peptides, 2066 transmembrane proteins and 756 secretory proteins.Transcriptional identification revealed 54 differentially expressed secretory proteins. Concurrently, 605, 130 and 2869 proteins were matched in the proprietary databases Carbohydrate-Active EnZymes database (CAZyme), Transporter Classification Database (TCDB) and Pathogen-Host Interactions database (PHI), respectively. And 96 and 36 DEGs were identified form PHI database and CAZyme database, respectively. In addition, contig00011.93 was an up-regulated DEG involving ATP-binding cassette metabolism in the procession of infection. In order to test relevance of gene predictions to GSB, DEGs with potential pathogenic relevance were revealed through transcriptome data analysis of Sc. strains pre- and post-infection of pumpkin. Interestingly, Sc. and Leptosphaeria maculans (Lm.) exhibited relatively similar with genome lengths, numbers of protein-coding genes and other characteristics. This work provides a foundation for future exploration of additional Sc. gene functions toward the development of more effective GSB control strategies.
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Affiliation(s)
- Qian Zhao
- Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Jianzhong Wu
- Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Liyan Zhang
- Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Chao Yan
- College of Agriculture, Northeast Agriculture University, Harbin, China
| | - Shukun Jiang
- Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Zhugang Li
- Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Dequan Sun
- Heilongjiang Academy of Agricultural Sciences, Harbin, China
| | - Yongcai Lai
- Heilongjiang Academy of Agricultural Sciences, Harbin, China.
| | - Zhenping Gong
- College of Agriculture, Northeast Agriculture University, Harbin, China.
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13
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Margaritopoulou T, Toufexi E, Kizis D, Balayiannis G, Anagnostopoulos C, Theocharis A, Rempelos L, Troyanos Y, Leifert C, Markellou E. Reynoutria sachalinensis extract elicits SA-dependent defense responses in courgette genotypes against powdery mildew caused by Podosphaera xanthii. Sci Rep 2020; 10:3354. [PMID: 32098979 PMCID: PMC7042220 DOI: 10.1038/s41598-020-60148-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 02/04/2020] [Indexed: 11/17/2022] Open
Abstract
Powdery mildew (PM) caused by Podosphaera xanthii is one of the most important courgette diseases with high yield losses and is currently controlled by fungicides and sulphur applications in conventional and organic production. Plant derived elicitors/inducers of resistance are natural compounds that induce resistance to pathogen attack and promote a faster and/or more robust activation of plant defense responses. Giant knotweed (Reynoutria sachalinensis, RS) extract is a known elicitor of plant defenses but its mode of action remains elusive. The aim of this study was to investigate the mechanisms of foliar RS applications and how these affect PM severity and crop performance when used alone or in combination with genetic resistance. RS foliar treatments significantly reduced conidial germination and PM severity on both an intermediate resistance (IR) and a susceptible (S) genotype. RS application triggered plant defense responses, which induced the formation of callose papillae, hydrogen peroxide accumulation and the Salicylic acid (SA) - dependent pathway. Increased SA production was detected along with increased p-coumaric and caffeic acid concentrations. These findings clearly indicate that RS elicits plant defenses notably as a consequence of SA pathway induction.
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Affiliation(s)
- Theoni Margaritopoulou
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Mycology, 8, St. Delta str., 145 61, Kifissia, Athens, Greece
| | - Eleftheria Toufexi
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Mycology, 8, St. Delta str., 145 61, Kifissia, Athens, Greece
- Newcastle University, Nafferton Ecological Farming Group, School of Agriculture Food and Rural Development, Newcastle upon Tyne, NE1 7RU, UK
| | - Dimosthenis Kizis
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Mycology, 8, St. Delta str., 145 61, Kifissia, Athens, Greece
| | - George Balayiannis
- Benaki Phytopathological Institute, Department of Pesticides Control & Phytopharmacy, Laboratory of Chemical Control of Pesticides, 8, St. Delta str., 145 61, Kifissia, Athens, Greece
| | - Christos Anagnostopoulos
- Benaki Phytopathological Institute, Department of Pesticides Control & Phytopharmacy, Laboratory of Pesticide Residues, 8, St. Delta str., 145 61, Kifissia, Athens, Greece
| | - Andreas Theocharis
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Mycology, 8, St. Delta str., 145 61, Kifissia, Athens, Greece
| | - Leonidas Rempelos
- Newcastle University, Nafferton Ecological Farming Group, School of Agriculture Food and Rural Development, Newcastle upon Tyne, NE1 7RU, UK
| | - Yerasimos Troyanos
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Non-Parasitic Diseases, 8, St. Delta str., 145 61, Kifissia, Athens, Greece
| | - Carlo Leifert
- Centre for Organics Research, Southern Cross University, Military Rd., Lismore, NSW, Australia
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Sognsvannsveien 9, Domus Medica, 0372, Oslo, Norway
| | - Emilia Markellou
- Benaki Phytopathological Institute, Department of Phytopathology, Laboratory of Mycology, 8, St. Delta str., 145 61, Kifissia, Athens, Greece.
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14
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Qiao H, Zhang B, Chen X, Su L, Jiao C, Chen S, Fan J, Liu H. Short peptides secreted by Bacillus subtilis inhibit the growth of mold on fresh-cut pumpkin (Cucurbita pepo). J Sci Food Agric 2020; 100:936-944. [PMID: 31487041 DOI: 10.1002/jsfa.10021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 08/30/2019] [Accepted: 08/30/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND This study investigates the efficacy of short peptides secreted by Bacillus subtilis for fungal inhibition in fresh-cut pumpkin and for maintaining its shelf life. RESULTS Low-molecular-weight filtrate (LC < 1000 Da) of B. subtilis culture (BC) significantly lowered the total number of molds on fresh-cut pumpkin compared with the untreated control and a BC group after storage. Low-molecular-weight filtrate prevented the deterioration of sensory quality in a pumpkin incision, and reduced pectinase activity. It also inhibited the growth of Phytophthora capsici and Penicillium chrysogenum, and the activity of β-1,3-glucan synthase (GS) secreted by both molds. Fifty-seven GS-inhibiting peptides were screened from 95 LC peptides with two to five amino acid residues. The two most potent peptides, AWYW and HWWY, had strongly suppressive effects on the growth of P. capsici and P. chrysogenum. CONCLUSION Our study demonstrated that short peptides present in B. subtilis culture can play an important role in the maintenance of fresh-cut pumpkin by suppressing fungal growth. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Huitian Qiao
- Beijing Key Laboratory of Agricultural Product Detection and Control for Spoilage Organisms and Pesticides, Food Science and Engineering College, Beijing University of Agriculture, Beijing, China
| | - Bo Zhang
- Department of Food Science and Engineering, College of Bioscience and Biotechnology, Beijing Forestry University, Beijing, China
| | - Xiangning Chen
- Beijing Key Laboratory of Agricultural Product Detection and Control for Spoilage Organisms and Pesticides, Food Science and Engineering College, Beijing University of Agriculture, Beijing, China
| | - Lijing Su
- Department of Food Science and Engineering, College of Bioscience and Biotechnology, Beijing Forestry University, Beijing, China
| | - Chang Jiao
- Beijing Key Laboratory of Agricultural Product Detection and Control for Spoilage Organisms and Pesticides, Food Science and Engineering College, Beijing University of Agriculture, Beijing, China
| | - Si Chen
- Beijing Key Laboratory of Agricultural Product Detection and Control for Spoilage Organisms and Pesticides, Food Science and Engineering College, Beijing University of Agriculture, Beijing, China
| | - Junfeng Fan
- Department of Food Science and Engineering, College of Bioscience and Biotechnology, Beijing Forestry University, Beijing, China
| | - Huijun Liu
- Beijing Key Laboratory of Agricultural Product Detection and Control for Spoilage Organisms and Pesticides, Food Science and Engineering College, Beijing University of Agriculture, Beijing, China
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15
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Newark MJ, Li P, Yang XP, Paret ML, Dufault NS. Comparing Stagonosporopsis spp. Fungicide Resistance Profiles in Florida and East China Cucurbit Production Systems. Plant Dis 2020; 104:129-136. [PMID: 31747352 DOI: 10.1094/pdis-02-19-0370-re] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Gummy stem blight, caused by Stagonosporopsis spp., is a major disease of cucurbits in the United States and China that is managed primarily through the use of fungicides. The objective of this study was to monitor and compare the recent fungicide resistance profiles of Stagonosporopsis spp. in Florida open-field and East China protected-structure production systems. Isolates of Stagonosporopsis spp. were evaluated for sensitivity to the commonly used fungicides azoxystrobin, boscalid, tebuconazole, and thiophanate-methyl at discriminatory rates of 0.096, 0.034, 0.128, and 100 mg/liter, respectively. Isolates were collected from Jiangsu, Jiangxi, Zhejiang, and Anhui provinces in China (n = 69), 12 counties in Florida (n = 89), and one county in Georgia (n = 6). More than 50% of isolates from Florida and East China were resistant to thiophanate-methyl. Boscalid resistance was detected in both isolate collections but was two times more frequent in China. Resistance to azoxystrobin was detected in 66% of isolates in Florida but only 7% in China. Tebuconazole was effective in controlling the mycelia growth of Stagonosporopsis spp. in both collections. The results indicate that both production systems currently face similar challenges related to the development of fungicide resistance in Stagonosporopsis spp. However, the resistance profiles are unique for both production systems.
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Affiliation(s)
- Mason J Newark
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611-0680, U.S.A
| | - Pingfang Li
- Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xing-Ping Yang
- Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Mathews L Paret
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611-0680, U.S.A
- North Florida Research and Education Center, University of Florida, Quincy, FL 32351, U.S.A
| | - Nicholas S Dufault
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611-0680, U.S.A
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16
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Abbaszadeh-Dahaji P, Baniasad-Asgari A, Hamidpour M. The effect of Cu-resistant plant growth-promoting rhizobacteria and EDTA on phytoremediation efficiency of plants in a Cu-contaminated soil. Environ Sci Pollut Res Int 2019; 26:31822-31833. [PMID: 31487012 DOI: 10.1007/s11356-019-06334-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 08/26/2019] [Indexed: 06/10/2023]
Abstract
Remediation of heavy metal-contaminated soils is essential for safe agricultural or urban land use, and phytoremediation is among the most effective methods. The success of phytoremediation relies on the size of the plant biomass and bioavailability of the metal for plant uptake. This research was carried out to determine the effect of Ethylenediaminetetraacetic acid (EDTA) ligand and Cu-resistant plant growth-promoting rhizobacteria (PGPR) on phytoremediation efficiency of selected plants as well as fractionation and bioavailability of copper (Cu) in a contaminated soil. The test conditions included three plant species (maize: Zea mays L., sunflower: Helianthus annuus L., and pumpkin: Cucurbita pepo L.) and six treatments, comprising two PGPR strains (Pseudomonas cedrina K4 and Stenotrophomonas sp. A22), two PGPR strains with EDTA, EDTA, and control (without PGPR and EDTA). The combination of EDTA and PGPR enhanced the Cu concentration in both shoot and root tissues and increased the plant biomass. The Cu specific uptake was at a maximum level in the shoots of pumpkin plants when treated with the PGPR strain K4 + EDTA (202 μg pot-1), and the minimum amount of Cu was recorded for sunflower with no PGPR or EDTA addition (29.6 μg pot-1). The result of the PGPR-EDTA treatments showed that the combined application of EDTA and PGPR increased the shoot Cu-specific uptake approximately fourfold in pumpkin. Pumpkin with the highest shoot Cu specific uptake and maize with the highest root Cu specific uptake were the most effective plants in phytoextraction and phytostabilization, respectively. The effectiveness of different PGPR-EDTA treatments in increasing Cu specific uptake by crop plants was assessed by measuring the amount of Cu extracted from the rhizosphere soil adhering to the roots of crop species, by the use of the single extractants Diethylenetriamine pentaacetic acid (DTPA), H2O, NH4NO3, and NH4OAc. PGPR-EDTA treatments increased the amount of water-extractable Cu from rhizosphere soils more than ten times that of the control. The combined application of the EDTA and PGPR reduced the carbonated Fe and Mn oxide-bound Cu in the contaminated soil, and increased the soluble and exchangeable concentration of Cu. Pumpkin, with high shoot biomass and the highest shoot Cu specific uptake was found to be the most effective field crop in phytoextraction of Cu from the contaminated soil. The results of this pot study demonstrated that the EDTA+PGPR treatment could play an important role in increasing the Cu bioavailability and specific uptake by plants, and thus increasing the phytoremediation efficiency of plants in Cu-contaminated areas.
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Affiliation(s)
- Payman Abbaszadeh-Dahaji
- Department of Soil Science, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
| | - Ayda Baniasad-Asgari
- Department of Soil Science, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
| | - Mohsen Hamidpour
- Department of Soil Science, Faculty of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
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17
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Keinath AP, Wechter WP, Rutter WB, Agudelo PA. Cucurbit Rootstocks Resistant to Fusarium oxysporum f. sp. niveum Remain Resistant When Coinfected by Meloidogyne incognita in the Field. Plant Dis 2019; 103:1383-1390. [PMID: 30958108 DOI: 10.1094/pdis-10-18-1869-re] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Interspecific hybrid squash (Cucurbita maxima × Cucurbita moschata) rootstocks used to graft watermelon (Citrullus lanatus var. lanatus) are resistant to Fusarium oxysporum f. sp. niveum, the fungus that causes Fusarium wilt of watermelon, but they are susceptible to Meloidogyne incognita, the southern root knot nematode. A new citron (Citrullus amarus) rootstock cultivar Carolina Strongback is resistant to F. oxysporum f. sp. niveum and M. incognita. The objective of this study was to determine if an interaction between M. incognita and F. oxysporum f. sp. niveum race 2 occurred on grafted or nongrafted triploid watermelon susceptible to F. oxysporum f. sp. niveum race 2. In 2016 and 2018, plants of nongrafted cultivar Fascination and Fascination grafted onto Carolina Strongback and interspecific hybrid squash cultivar Carnivor were inoculated or not inoculated with M. incognita before transplanting into field plots infested or not infested with F. oxysporum f. sp. niveum race 2. Incidence of Fusarium wilt and area under the disease progress curve did not differ when hosts were inoculated with F. oxysporum f. sp. niveum alone or F. oxysporum f. sp. niveum and M. incognita together. Fusarium wilt was greater on nongrafted watermelon (78% mean incidence) than on both grafted rootstocks and lower on Carnivor (1% incidence) than on Carolina Strongback (12% incidence; P ≤ 0.01). Plants not inoculated with F. oxysporum f. sp. niveum did not wilt. At the end of the season, Carnivor had a greater percentage of the root system galled than the other two hosts, whereas galling did not differ on Fascination and Carolina Strongback. F. oxysporum f. sp. niveum reduced marketable weight of nongrafted Fascination with and without coinoculation with M. incognita. M. incognita reduced marketable weight of Fascination grafted onto Carnivor compared with noninoculated, nongrafted Fascination. In conclusion, cucurbit rootstocks that are susceptible and resistant to M. incognita retain resistance to F. oxysporum f. sp. niveum when they are coinfected with M. incognita.
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Affiliation(s)
- Anthony P Keinath
- 1 Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634-0310; and
| | - W Patrick Wechter
- 2 Agricultural Research Service, U.S. Vegetable Laboratory, U.S. Department of Agriculture, Charleston, SC 29414-5329
| | - William B Rutter
- 2 Agricultural Research Service, U.S. Vegetable Laboratory, U.S. Department of Agriculture, Charleston, SC 29414-5329
| | - Paula A Agudelo
- 1 Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634-0310; and
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18
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Martínez-Cruz J, Romero D, De Vicente A, Pérez-García A. Transformation by growth onto agro-infiltrated tissues (TGAT), a simple and efficient alternative for transient transformation of the cucurbit powdery mildew pathogen Podosphaera xanthii. Mol Plant Pathol 2018; 19:2502-2515. [PMID: 30073764 PMCID: PMC6638186 DOI: 10.1111/mpp.12722] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/21/2018] [Accepted: 06/24/2018] [Indexed: 05/30/2023]
Abstract
A major limitation of molecular studies in powdery mildew fungi (Erysiphales) is their genetic intractability. This is because they are obligate biotrophs. In these parasites, biotrophy is determined by the presence of haustoria, which are specialized structures of parasitism that play an essential role in the acquisition of nutrients and the deliverance of effectors. Podosphaera xanthii is the main causal agent of cucurbit powdery mildew and a major limitation for crop productivity. In a previous study using P. xanthii conidia, we showed, for the first time, the transformation of powdery mildew fungi by Agrobacterium tumefaciens. In this work, we hypothesized that the haustorium could also act as a natural route for the acquisition of DNA. To test our hypothesis, melon cotyledons were agro-infiltrated with A. tumefaciens that contained diverse transfer DNA (T-DNA) constructs harbouring different marker genes under the control of fungal promoters and, after elimination of the bacterium, the cotyledons were subsequently inoculated with P. xanthii conidia. Our results conclusively demonstrated the transfer of different T-DNAs from A. tumefaciens to P. xanthii, including two fungicide resistance markers (hph and tub2), a reporter gene (gfp) and a translational fusion (cfp-PxEC2). These results were further supported by the co-localization of translational fluorescent fusions of A. tumefaciens VirD2 and P. xanthii Rab5 proteins into small vesicles of haustorial and hyphal cells, suggesting endocytosis as the mechanism for T-DNA uptake, presumably by the haustorium. From our perspective, transformation by growth onto agro-infiltrated tissues (TGAT) is the easiest and most reliable method for the transient transformation of powdery mildew fungi.
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Affiliation(s)
- Jesús Martínez-Cruz
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, 29071, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, 29071, Spain
| | - Diego Romero
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, 29071, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, 29071, Spain
| | - Antonio De Vicente
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, 29071, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, 29071, Spain
| | - Alejandro Pérez-García
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, 29071, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, 29071, Spain
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19
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Keinath AP, Agudelo PA. Retention of Resistance to Fusarium oxysporum f. sp. niveum in Cucurbit Rootstocks Infected by Meloidogyne incognita. Plant Dis 2018; 102:1820-1827. [PMID: 30125172 DOI: 10.1094/pdis-12-17-1916-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Interspecific hybrid squash (Cucurbita maxima × C. moschata 'Strong Tosa') and bottle gourd (Lagenaria siceraria 'Macis') rootstocks are resistant to Fusarium oxysporum f. sp. niveum but susceptible to Meloidogyne incognita (Southern root-knot nematode). Coinfection of Early Prolific Straightneck summer squash (C. pepo) with root-knot nematode and F. oxysporum f. sp. niveum has been reported to increase susceptibility to Fusarium wilt. The objectives of this study were to determine whether such an interaction occurred between M. incognita and F. oxysporum f. sp. niveum races 1 and 2 on Strong Tosa, Macis, and watermelon cultivars Fascination (resistant to race 1) and Tri-X 313 (susceptible to both races). Hosts were inoculated in a greenhouse with one of four pathogen treatments: F. oxysporum f. sp. niveum, M. incognita, both pathogens, or neither pathogen. Galling was present on ≥10% of the root systems of 90% of the plants inoculated with M. incognita. Bottle gourd had less galling than interspecific hybrid squash. Plants not inoculated with F. oxysporum f. sp. niveum did not wilt. Four weeks after inoculation, incidence and severity of Fusarium wilt and recovery of F. oxysporum did not differ for any hosts inoculated with F. oxysporum f. sp. niveum alone and F. oxysporum f. sp. niveum plus M. incognita (host-treatment interactions not significant). In general, Early Prolific Straightneck grouped with the F. oxysporum f. sp. niveum-resistant rootstocks when inoculated with F. oxysporum f. sp. niveum race 2 and with the susceptible watermelon when inoculated with race 1, regardless of inoculation with M. incognita. Recovery of F. oxysporum from stems of inoculated watermelon was greater than recovery from the other three hosts, regardless of nematode inoculation. In conclusion, our experiments do not support the hypothesis that resistance to F. oxysporum f. sp. niveum in cucurbit rootstocks or resistant watermelon cultivars would be compromised when M. incognita infects the roots.
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Affiliation(s)
- Anthony P Keinath
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634-0310
| | - Paula A Agudelo
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634-0310
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20
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Zhang X, Babadoost M. Characteristics of Xanthomonas cucurbitae Isolates from Pumpkins and Survival of the Bacterium in Pumpkin Seeds. Plant Dis 2018; 102:1779-1784. [PMID: 30125182 DOI: 10.1094/pdis-08-17-1216-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This study was conducted to determine characteristics of Xanthomonas cucurbitae, the causal agent of bacterial spot of pumpkin, and survival of the bacterium in pumpkin seeds. Fourteen X. cucurbitae isolates from the north central region of the United States, along with the X. cucurbitae strain 23378 from the American Type Culture Collection, were included in this study. The range of minimum, optimum, and maximum temperatures for colony development of X. cucurbitae were 4 to 6°C, 24 to 30°C, and 34 to 36°C, respectively. Optimum pH for colony development ranged from 6.5 to 8.0. Leaves of 3-week-old pumpkins 'Howden' and 'Dickinson' were inoculated with X. cucurbitae isolates (108 CFU/ml). There was a significant difference in the postinoculation periods for appearance of bacterial lesions on the leaves among the isolates; however, there was no significant difference in diameters of the lesions on each of the pumpkin cultivar 7 days after inoculation. Four of the isolates caused significantly larger lesions on 'Dickinson' leaves than 'Howden' leaves. Naturally infected 'Howden' pumpkin and inoculated 'Dickinson' pumpkin seeds with X. cucurbitae were stored at 4 and 22°C. X. cucurbitae was isolated from both naturally infected and inoculated seeds 24 months after storage at both 4 and 22°C, and the isolated bacteria were pathogenic.
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Affiliation(s)
- X Zhang
- Department of Crop Sciences, University of Illinois, Urbana 61801
| | - M Babadoost
- Department of Crop Sciences, University of Illinois, Urbana 61801
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21
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Neufeld KN, Keinath AP, Ojiambo PS. Evaluation of a Model for Predicting the Infection Risk of Squash and Cantaloupe by Pseudoperonospora cubensis. Plant Dis 2018; 102:855-862. [PMID: 30673386 DOI: 10.1094/pdis-07-17-1046-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Infection risk models of downy mildew of cucumber caused by Pseudoperonospora cubensis were evaluated for their performance in predicting the infection risk of squash and cantaloupe plants under field conditions. Experiments were conducted from 2012 to 2014 in Clayton, NC and Charleston, SC, where disease-free potted plants were exposed to weather conditions during a 24- and 48-h period (hereafter 24- and 48-h models, respectively) within a plot with naturally occurring inoculum. Exposed plants were subsequently placed in a growth chamber where they were monitored for disease symptoms, which was indicative of a successful infection. Disease severity was assessed after 7 days as the proportion of leaf area with disease symptoms. Two predictor variables, day temperature and hours of relative humidity >80% during each exposure were used as inputs to generate model predictions that were compared with observed data. The threshold probability on the receiver operating characteristic (ROC) curve that minimized the overall error rate for the 24-h model was 0.85 for both squash and cantaloupe. The 24-h model was consistently more accurate than the 48-h model in predicting the infection risk for the two hosts. The accuracy of the 24-h model as estimated using area under ROC curve ranged from 0.75 to 0.81, with a correct classification rate ranging from 0.69 to 0.74 across the two hosts. Specificity rates for the model ranged from 0.81 to 0.84, while the sensitivity rates ranged from 0.58 to 0.67. Optimal decisions thresholds (POT) developed based on estimates of economic damage and costs of management showed that POT was dependent on the probability of disease occurrence, with the benefit of using the 24-h model for making management decisions being greatest at low levels of probability of disease occurrence. This 24-h model, previously developed using cucumber as the host, resulted in accurate estimates of the daily infection risk of squash and cantaloupe and could potentially be useful when incorporated into a decision support tool to guide fungicide applications to manage downy mildew in these other cucurbit host types.
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Affiliation(s)
- Katie N Neufeld
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695
| | - Anthony P Keinath
- Coastal Research and Education Center, Clemson University, Charleston, SC 29634
| | - Peter S Ojiambo
- Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh NC 27695
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22
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Newberry EA, Babu B, Roberts PD, Dufault NS, Goss EM, Jones JB, Paret ML. Molecular Epidemiology of Pseudomonas syringae pv. syringae Causing Bacterial Leaf Spot of Watermelon and Squash in Florida. Plant Dis 2018; 102:511-518. [PMID: 30673490 DOI: 10.1094/pdis-07-17-1002-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
From 2013 to 2014, bacterial leaf spot epidemics incited by Pseudomonas syringae pv. syringae affected an estimated 3,000 ha of watermelon and squash in Florida, and caused foliar blighting and transplant losses in severely affected fields. To investigate the diversity of the causal agent, we isolated 28 P. syringae strains from diseased plants grown in 10 Florida and Georgia counties over the course of 2 years. Strains were confirmed as P. syringae through sequence analysis of the 16S ribosomal RNA, phenotypic, and biochemical profiling; however, 20 displayed an atypical phenotype by exhibiting nonfluorescent activity on King's medium B agar and being negative for ice-nucleating activity. Multilocus sequence analysis and BOX polymerase chain reaction revealed the presence of two haplotypes among the collected strains that grouped into two distinct clades within P. syringae phylogroup 2. Pathogenicity testing showed that watermelon, cantaloupe, and squash seedlings were susceptible to a majority of these strains. Although both haplotypes were equally virulent on cantaloupe, they differed in virulence on watermelon and squash. The distribution of one haplotype in 9 of 10 Florida and Georgia counties sampled indicated that these epidemics were associated with the recent introduction of a novel clonal P. syringae lineage throughout major watermelon production areas in Florida.
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Affiliation(s)
- E A Newberry
- North Florida Research and Education Center, University of Florida, Quincy
| | - B Babu
- North Florida Research and Education Center, University of Florida, Quincy
| | - P D Roberts
- Southwest Florida Research and Education Center, University of Florida, Immokalee
| | - N S Dufault
- Department of Plant Pathology, University of Florida, Gainesville
| | - E M Goss
- Department of Plant Pathology, University of Florida, Gainesville
| | - J B Jones
- Department of Plant Pathology, University of Florida, Gainesville
| | - M L Paret
- North Florida Research and Education Center, University of Florida, Quincy
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23
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Zeng H, Zhai X, Xie M, Liu Q. Fluorescein Isothiocyanate Labeling Antigen-Based Immunoassay Strip for Rapid Detection of Acidovorax citrulli. Plant Dis 2018; 102:527-532. [PMID: 30673481 DOI: 10.1094/pdis-06-17-0903-re] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A simple and fast immunoassay strip to detect Acidovorax citrulli (Ac) using fluorescein isothiocyanate as a marker was developed. Fluorescein isothiocyanate (FITC) was added to sample culture medium for bacteria incubation, and the bacteria could emit a yellow-green fluorescence under ultraviolet light and become a fluorescent probe. This immunofluorescence strip (IFS) was based on the binding between fluorescent bacteria and the unlabeled monoclonal antibody (McAb) immobilized on the test area in nitrocellulose membrane. The detection limit of the strip was 106 CFU/ml with a result that could be observed within 10 min. The IFS could detect eight strains of Ac and display no cross-reactions with 30 other pathogenic strains. The detection results would not be affected by impurities in plant or unknown microorganisms in natural field samples and were consistent with PCR results, indicating that the IFS has high accuracy. This is the first report of using only one unlabeled McAb to develop a direct-type immunofluorescence strip for the rapid detection of Ac. The IFS reduced detection time and simplified operation procedures compared with the traditional enzyme-linked immunosorbent assay (ELISA) and PCR methods. In addition, this simple and inexpensive method will play a significant role in monitoring plant pathogens on field detection.
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Affiliation(s)
- Haijuan Zeng
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Xuzhao Zhai
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Manman Xie
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Qing Liu
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
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24
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Harris-Valle C, Esqueda M, Gutiérrez A, Castellanos AE, Gardea AA, Berbara R. Physiological response of Cucurbita pepo var. pepo mycorrhized by Sonoran desert native arbuscular fungi to drought and salinity stresses. Braz J Microbiol 2018; 49:45-53. [PMID: 28887008 PMCID: PMC5790584 DOI: 10.1016/j.bjm.2017.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 03/31/2017] [Accepted: 04/05/2017] [Indexed: 11/21/2022] Open
Abstract
Plants response to symbiosis with arbuscular mycorrhizal fungi (AMF) under water stress is important to agriculture. Under abiotic stress conditions native fungi are more effective than exotics in improving plant growth and water status. Mycorrhization efficiency is related to soil fungi development and energy cost-benefit ratio. In this study, we assessed the effect on growth, water status and energy metabolism of Cucurbita pepo var. pepo when inoculated with native AMF from the Sonoran desert Mexico (mixed isolate and field consortium), and compared with an exotic species from a temperate region, under drought, low and high salinity conditions. Dry weights, leaf water content, water and osmotic potentials, construction costs, photochemistry and mycorrhization features were quantified. Under drought and low salinity conditions, the mixed isolate increased plant growth and leaf water content. Leaf water potential was increased only by the field consortium under drought conditions (0.5-0.9MPa). Under high salinity, the field consortium increased aerial dry weight (more than 1g) and osmotic potential (0.54MPa), as compared to non-mycorrhized controls. Plants inoculated with native AMF, which supposedly diminish the effects of stress, exhibited low construction costs, increased photochemical capacity, and grew larger external mycelia in comparison to the exotic inoculum.
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Affiliation(s)
| | - Martín Esqueda
- Centro de Investigación en Alimentación y Desarrollo, Hermosillo, Mexico.
| | - Aldo Gutiérrez
- Centro de Investigación en Alimentación y Desarrollo, Hermosillo, Mexico
| | | | - Alfonso A Gardea
- Centro de Investigación en Alimentación y Desarrollo, Hermosillo, Mexico
| | - Ricardo Berbara
- Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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25
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Sapak Z, Salam MU, Minchinton EJ, MacManus GPV, Joyce DC, Galea VJ. POMICS: A Simulation Disease Model for Timing Fungicide Applications in Management of Powdery Mildew of Cucurbits. Phytopathology 2017; 107:1022-1031. [PMID: 28517959 DOI: 10.1094/phyto-11-16-0413-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A weather-based simulation model, called Powdery Mildew of Cucurbits Simulation (POMICS), was constructed to predict fungicide application scheduling to manage powdery mildew of cucurbits. The model was developed on the principle that conditions favorable for Podosphaera xanthii, a causal pathogen of this crop disease, generate a number of infection cycles in a single growing season. The model consists of two components that (i) simulate the disease progression of P. xanthii in secondary infection cycles under natural conditions and (ii) predict the disease severity with application of fungicides at any recurrent disease cycles. The underlying environmental factors associated with P. xanthii infection were quantified from laboratory and field studies, and also gathered from literature. The performance of the POMICS model when validated with two datasets of uncontrolled natural infection was good (the mean difference between simulated and observed disease severity on a scale of 0 to 5 was 0.02 and 0.05). In simulations, POMICS was able to predict high- and low-risk disease alerts. Furthermore, the predicted disease severity was responsive to the number of fungicide applications. Such responsiveness indicates that the model has the potential to be used as a tool to guide the scheduling of judicious fungicide applications.
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Affiliation(s)
- Z Sapak
- First author: Faculty of Plantation and Agrotechnology, MARA University of Technology, Shah Alam, Selangor, 40450, Malaysia; first, fifth, and sixth authors: School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, QLD, Australia; second author: Food and Agriculture Organization of the United Nations (FAO), FAO Representation in Bangladesh, House 37; Road 08; Dhanmondi R/A, Dhaka-1205, Bangladesh; third author: Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, VIC 3047, Australia; fourth author: Horticulture and Forestry Science, Agri-Science Queensland, Department of Employment, Economic Development and Innovation, PO Box 15, Ayr, QLD 4807, Australia; and fifth author: Department of Agriculture and Fisheries, Level 2C West, Ecosciences Precinct, Box 267, Brisbane, QLD 4001, Australia
| | - M U Salam
- First author: Faculty of Plantation and Agrotechnology, MARA University of Technology, Shah Alam, Selangor, 40450, Malaysia; first, fifth, and sixth authors: School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, QLD, Australia; second author: Food and Agriculture Organization of the United Nations (FAO), FAO Representation in Bangladesh, House 37; Road 08; Dhanmondi R/A, Dhaka-1205, Bangladesh; third author: Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, VIC 3047, Australia; fourth author: Horticulture and Forestry Science, Agri-Science Queensland, Department of Employment, Economic Development and Innovation, PO Box 15, Ayr, QLD 4807, Australia; and fifth author: Department of Agriculture and Fisheries, Level 2C West, Ecosciences Precinct, Box 267, Brisbane, QLD 4001, Australia
| | - E J Minchinton
- First author: Faculty of Plantation and Agrotechnology, MARA University of Technology, Shah Alam, Selangor, 40450, Malaysia; first, fifth, and sixth authors: School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, QLD, Australia; second author: Food and Agriculture Organization of the United Nations (FAO), FAO Representation in Bangladesh, House 37; Road 08; Dhanmondi R/A, Dhaka-1205, Bangladesh; third author: Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, VIC 3047, Australia; fourth author: Horticulture and Forestry Science, Agri-Science Queensland, Department of Employment, Economic Development and Innovation, PO Box 15, Ayr, QLD 4807, Australia; and fifth author: Department of Agriculture and Fisheries, Level 2C West, Ecosciences Precinct, Box 267, Brisbane, QLD 4001, Australia
| | - G P V MacManus
- First author: Faculty of Plantation and Agrotechnology, MARA University of Technology, Shah Alam, Selangor, 40450, Malaysia; first, fifth, and sixth authors: School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, QLD, Australia; second author: Food and Agriculture Organization of the United Nations (FAO), FAO Representation in Bangladesh, House 37; Road 08; Dhanmondi R/A, Dhaka-1205, Bangladesh; third author: Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, VIC 3047, Australia; fourth author: Horticulture and Forestry Science, Agri-Science Queensland, Department of Employment, Economic Development and Innovation, PO Box 15, Ayr, QLD 4807, Australia; and fifth author: Department of Agriculture and Fisheries, Level 2C West, Ecosciences Precinct, Box 267, Brisbane, QLD 4001, Australia
| | - D C Joyce
- First author: Faculty of Plantation and Agrotechnology, MARA University of Technology, Shah Alam, Selangor, 40450, Malaysia; first, fifth, and sixth authors: School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, QLD, Australia; second author: Food and Agriculture Organization of the United Nations (FAO), FAO Representation in Bangladesh, House 37; Road 08; Dhanmondi R/A, Dhaka-1205, Bangladesh; third author: Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, VIC 3047, Australia; fourth author: Horticulture and Forestry Science, Agri-Science Queensland, Department of Employment, Economic Development and Innovation, PO Box 15, Ayr, QLD 4807, Australia; and fifth author: Department of Agriculture and Fisheries, Level 2C West, Ecosciences Precinct, Box 267, Brisbane, QLD 4001, Australia
| | - V J Galea
- First author: Faculty of Plantation and Agrotechnology, MARA University of Technology, Shah Alam, Selangor, 40450, Malaysia; first, fifth, and sixth authors: School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, QLD, Australia; second author: Food and Agriculture Organization of the United Nations (FAO), FAO Representation in Bangladesh, House 37; Road 08; Dhanmondi R/A, Dhaka-1205, Bangladesh; third author: Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, VIC 3047, Australia; fourth author: Horticulture and Forestry Science, Agri-Science Queensland, Department of Employment, Economic Development and Innovation, PO Box 15, Ayr, QLD 4807, Australia; and fifth author: Department of Agriculture and Fisheries, Level 2C West, Ecosciences Precinct, Box 267, Brisbane, QLD 4001, Australia
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26
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van Dam P, Fokkens L, Ayukawa Y, van der Gragt M, Ter Horst A, Brankovics B, Houterman PM, Arie T, Rep M. A mobile pathogenicity chromosome in Fusarium oxysporum for infection of multiple cucurbit species. Sci Rep 2017; 7:9042. [PMID: 28831051 PMCID: PMC5567276 DOI: 10.1038/s41598-017-07995-y] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/05/2017] [Indexed: 12/20/2022] Open
Abstract
The genome of Fusarium oxysporum (Fo) consists of a set of eleven 'core' chromosomes, shared by most strains and responsible for housekeeping, and one or several accessory chromosomes. We sequenced a strain of Fo f.sp. radicis-cucumerinum (Forc) using PacBio SMRT sequencing. All but one of the core chromosomes were assembled into single contigs, and a chromosome that shows all the hallmarks of a pathogenicity chromosome comprised two contigs. A central part of this chromosome contains all identified candidate effector genes, including homologs of SIX6, SIX9, SIX11 and SIX 13. We show that SIX6 contributes to virulence of Forc. Through horizontal chromosome transfer (HCT) to a non-pathogenic strain, we also show that the accessory chromosome containing the SIX gene homologs is indeed a pathogenicity chromosome for cucurbit infection. Conversely, complete loss of virulence was observed in Forc016 strains that lost this chromosome. We conclude that also a non-wilt-inducing Fo pathogen relies on effector proteins for successful infection and that the Forc pathogenicity chromosome contains all the information necessary for causing root rot of cucurbits. Three out of nine HCT strains investigated have undergone large-scale chromosome alterations, reflecting the remarkable plasticity of Fo genomes.
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Affiliation(s)
- Peter van Dam
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Like Fokkens
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Yu Ayukawa
- Laboratory of Plant Pathology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology (TUAT), Fuchu, Tokyo, Japan
| | - Michelle van der Gragt
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Anneliek Ter Horst
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Petra M Houterman
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Tsutomu Arie
- Laboratory of Plant Pathology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology (TUAT), Fuchu, Tokyo, Japan
| | - Martijn Rep
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.
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Yang R, Liu Y, Zhou Z, Sheng J, Meng D. Microelectric Current Treatment Enhanced Biodegradation of Pumpkin Lignocelluloses by Trichoderma reesei RUT-C30. J Agric Food Chem 2017; 65:4668-4675. [PMID: 28537388 DOI: 10.1021/acs.jafc.7b00902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A homemade microcurrent reactor was used to treat the fermentation of Trichoderma reesei. Results indicated that the yield of saccharides for T. reesei RUT-C30 cultivated in pumpkin lignocellulose broth reaches 38.86% (w/w) when a microcurrent treatment (20 mA, at the 48th hour for 60 min) was carried out, which is significantly higher than the control group (p < 0.05). Additionally, activities of endoglucanase, cellobiohydrolase, xylanase, and pectinase were significantly increased in days 3-7. Furthermore, the fungal growth was facilitated by microelectric treatment, showing a 0.57-fold increase of spore numbers at the sixth day of cultivation. Besides, the monosaccharide composition, including glucose (1.03 mg/mL), xylose (0.12 mg/mL), arabinose (0.31 mg/mL), and fructose (0.13 mg/mL), extracted from the reactor was higher than that without the current treatment. In this work, we improved the biodegradation of lignocellulosic wastes by applying a microcurrent to lignocellulose-degrading fungal cultures and provided a new idea for the lignocellulose material pretreatment and bioconversion.
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Affiliation(s)
- Rui Yang
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology , Tianjin 300457, People's Republic of China
- Tianjin Food Safety & Low Carbon Manufacturing Collaborative Innovation Center , Tianjin 300457, People's Republic of China
| | - Yuqian Liu
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology , Tianjin 300457, People's Republic of China
| | - Zhongkai Zhou
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology , Tianjin 300457, People's Republic of China
- Tianjin Food Safety & Low Carbon Manufacturing Collaborative Innovation Center , Tianjin 300457, People's Republic of China
| | - Jiping Sheng
- School of Agricultural Economics and Rural Development, Renmin University of China , Beijing 100872, People's Republic of China
| | - Demei Meng
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science and Technology , Tianjin 300457, People's Republic of China
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28
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Martínez-Cruz J, Romero D, de Vicente A, Pérez-García A. Transformation of the cucurbit powdery mildew pathogen Podosphaera xanthii by Agrobacterium tumefaciens. New Phytol 2017; 213:1961-1973. [PMID: 27864969 DOI: 10.1111/nph.14297] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/21/2016] [Indexed: 06/06/2023]
Abstract
The obligate biotrophic fungal pathogen Podosphaera xanthii is the main causal agent of powdery mildew in cucurbit crops all over the world. A major limitation of molecular studies of powdery mildew fungi (Erysiphales) is their genetic intractability. In this work, we describe a robust method based on the promiscuous transformation ability of Agrobacterium tumefaciens for reliable transformation of P. xanthii. The A. tumefaciens-mediated transformation (ATMT) system yielded transformants of P. xanthii with diverse transferred DNA (T-DNA) constructs. Analysis of the resultant transformants showed the random integration of T-DNA into the P. xanthii genome. The integrations were maintained in successive generations in the presence of selection pressure. Transformation was found to be transient, because in the absence of selection agent, the introduced genetic markers were lost due to excision of T-DNA from the genome. The ATMT system represents a potent tool for genetic manipulation of P. xanthii and will likely be useful for studying other biotrophic fungi. We hope that this method will contribute to the development of detailed molecular studies of the intimate interaction established between powdery mildew fungi and their host plants.
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Affiliation(s)
- Jesús Martínez-Cruz
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' - Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, 29071, Spain
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga. Bulevar Louis Pasteur 31, Málaga, 29071, Spain
| | - Diego Romero
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' - Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, 29071, Spain
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga. Bulevar Louis Pasteur 31, Málaga, 29071, Spain
| | - Antonio de Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' - Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, 29071, Spain
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga. Bulevar Louis Pasteur 31, Málaga, 29071, Spain
| | - Alejandro Pérez-García
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' - Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, 29071, Spain
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga. Bulevar Louis Pasteur 31, Málaga, 29071, Spain
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Holdsworth WL, LaPlant KE, Bell DC, Jahn MM, Mazourek M. Cultivar-Based Introgression Mapping Reveals Wild Species-Derived Pm-0, the Major Powdery Mildew Resistance Locus in Squash. PLoS One 2016; 11:e0167715. [PMID: 27936008 PMCID: PMC5147965 DOI: 10.1371/journal.pone.0167715] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 11/18/2016] [Indexed: 11/19/2022] Open
Abstract
Powdery mildew is a major fungal disease on squash and pumpkin (Cucurbita spp.) in the US and throughout the world. Genetic resistance to the disease is not known to occur naturally within Cucurbita pepo and only infrequently in Cucurbita moschata, but has been achieved in both species through the introgression of a major resistance gene from the wild species Cucurbita okeechobeensis subsp. martinezii. At present, this gene, Pm-0, is used extensively in breeding, and is found in nearly all powdery mildew-resistant C. pepo and C. moschata commercial cultivars. In this study, we mapped C. okeechobeensis subsp. martinezii-derived single nucleotide polymorphism (SNP) alleles in a set of taxonomically and morphologically diverse and resistant C. pepo and C. moschata cultivars bred at Cornell University that, by common possession of Pm-0, form a shared-trait introgression panel. High marker density was achieved using genotyping-by-sequencing, which yielded over 50,000 de novo SNP markers in each of the three Cucurbita species genotyped. A single 516.4 kb wild-derived introgression was present in all of the resistant cultivars and absent in a diverse set of heirlooms that predated the Pm-0 introgression. The contribution of this interval to powdery mildew resistance was confirmed by association mapping in a C. pepo cultivar panel that included the Cornell lines, heirlooms, and 68 additional C. pepo cultivars and with an independent F2 population derived from C. okeechobeensis subsp. martinezii x C. moschata. The interval was refined to a final candidate interval of 76.4 kb and CAPS markers were developed inside this interval to facilitate marker-assisted selection.
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Affiliation(s)
- William L. Holdsworth
- Section of Plant Breeding and Genetics, School of Integrative Plant Sciences, Cornell University, Ithaca, NY, United States of America
- Rupp Seeds, Inc., Wauseon, OH, United States of America
| | - Kyle E. LaPlant
- Section of Plant Breeding and Genetics, School of Integrative Plant Sciences, Cornell University, Ithaca, NY, United States of America
| | - Duane C. Bell
- Rupp Seeds, Inc., Wauseon, OH, United States of America
| | - Molly M. Jahn
- Department of Agronomy, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Michael Mazourek
- Section of Plant Breeding and Genetics, School of Integrative Plant Sciences, Cornell University, Ithaca, NY, United States of America
- * E-mail:
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Vela-Corcía D, Bautista R, de Vicente A, Spanu PD, Pérez-García A. De novo Analysis of the Epiphytic Transcriptome of the Cucurbit Powdery Mildew Fungus Podosphaera xanthii and Identification of Candidate Secreted Effector Proteins. PLoS One 2016; 11:e0163379. [PMID: 27711117 PMCID: PMC5053433 DOI: 10.1371/journal.pone.0163379] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 09/06/2016] [Indexed: 01/09/2023] Open
Abstract
The cucurbit powdery mildew fungus Podosphaera xanthii is a major limiting factor for cucurbit production worldwide. Despite the fungus’s agronomic and economic importance, very little is known about fundamental aspects of P. xanthii biology, such as obligate biotrophy or pathogenesis. To design more durable control strategies, genomic information about P. xanthii is needed. Powdery mildews are fungal pathogens with large genomes compared with those of other fungi, which contain vast amounts of repetitive DNA sequences, much of which is composed of retrotransposons. To reduce genome complexity, in this work we aimed to obtain and analyse the epiphytic transcriptome of P. xanthii as a starting point for genomic research. Total RNA was isolated from epiphytic fungal material, and the corresponding cDNA library was sequenced using a 454 GS FLX platform. Over 676,562 reads were obtained and assembled into 37,241 contigs. Annotation data identified 8,798 putative genes with different orthologues. As described for other powdery mildew fungi, a similar set of missing core ascomycete genes was found, which may explain obligate biotrophy. To gain insight into the plant-pathogen relationships, special attention was focused on the analysis of the secretome. After this analysis, 137 putative secreted proteins were identified, including 53 candidate secreted effector proteins (CSEPs). Consistent with a putative role in pathogenesis, the expression profile observed for some of these CSEPs showed expression maxima at the beginning of the infection process at 24 h after inoculation, when the primary appressoria are mostly formed. Our data mark the onset of genomics research into this very important pathogen of cucurbits and shed some light on the intimate relationship between this pathogen and its host plant.
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Affiliation(s)
- David Vela-Corcía
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC), Departamento de Microbiología, Facultad de Ciencias, Málaga, Spain
| | - Rocío Bautista
- Plataforma Andaluza de Bioinformática, Edificio de Bioinnovación, Parque Tecnológico de Andalucía, Málaga, Spain
| | - Antonio de Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC), Departamento de Microbiología, Facultad de Ciencias, Málaga, Spain
| | - Pietro D. Spanu
- Department of Life Sciences, Imperial College London, United Kingdom
| | - Alejandro Pérez-García
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC), Departamento de Microbiología, Facultad de Ciencias, Málaga, Spain
- * E-mail:
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31
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Abstract
Bacterial wilt is one of the most destructive diseases of cucurbits in the Midwestern and Northeastern United States. Although the disease has been studied since 1900, host colonization dynamics remain unclear. Cucumis- and Cucurbita-derived strains exhibit host preference for the cucurbit genus from which they were isolated. We constructed a bioluminescent strain of Erwinia tracheiphila (TedCu10-BL#9) and colonization of different cucurbit hosts was monitored. At the second-true-leaf stage, Cucumis melo plants were inoculated with TedCu10-BL#9 via wounded leaves, stems, and roots. Daily monitoring of colonization showed bioluminescent bacteria in the inoculated leaf and petiole beginning 1 day postinoculation (DPI). The bacteria spread to roots via the stem by 2 DPI, reached the plant extremities 4 DPI, and the plant wilted 6 DPI. However, Cucurbita plants inoculated with TedCu10-BL#9 did not wilt, even at 35 DPI. Bioluminescent bacteria were detected 6 DPI in the main stem of squash and pumpkin plants, which harbored approximately 10(4) and 10(1) CFU/g, respectively, of TedCu10-BL#9 without symptoms. Although significantly less systemic plant colonization was observed in nonpreferred host Cucurbita plants compared with preferred hosts, the mechanism of tolerance of Cucurbita plants to E. tracheiphila strains from Cucumis remains unknown.
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Affiliation(s)
- Cláudio M Vrisman
- First, second, and fourth authors: Department of Plant Pathology, and second and third authors: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691
| | - Loïc Deblais
- First, second, and fourth authors: Department of Plant Pathology, and second and third authors: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691
| | - Gireesh Rajashekara
- First, second, and fourth authors: Department of Plant Pathology, and second and third authors: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691
| | - Sally A Miller
- First, second, and fourth authors: Department of Plant Pathology, and second and third authors: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691
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Abstract
BACKGROUND Endophytes are microbes that colonize plant internal tissues without causing disease. In particular, seed-associated endophytes may be vectors for founder microbes that establish the plant microbiome, which may subsequently contribute beneficial functions to their host plants including nutrient acquisition and promotion of plant growth. The Cucurbitaceae family of gourds (e.g., cucumbers, melons, pumpkin, squash), including its fruits and seeds, is widely consumed by humans. However, there is limited data concerning the taxonomy and functions of seed-associated endophytes across the Cucurbitaceae family. Here, bacteria from surface-sterilized seeds of 21 curcurbit varieties belonging to seven economically important species were cultured, classified using 16S rRNA gene sequencing, and subjected to eight in vitro functional tests. RESULTS In total, 169 unique seed-associated bacterial strains were cultured from selected cucurbit seeds. Interestingly, nearly all strains belonged to only two phyla (Firmicutes, Proteobacteria) and only one class within each phyla (Bacilli, γ-proteobacteria, respectively). Bacillus constituted 50 % of all strains and spanned all tested cucurbit species. Paenibacillus was the next most common genus, while strains of Enterobacteriaceae and lactic acid bacteria were also cultured. Phylogenetic trees showed limited taxonomic clustering of strains by host species. Surprisingly, 33 % of strains produced the plant hormone, indole-3-acetic acid (auxin), known to stimulate the growth of fruits/gourds and nutrient-acquiring roots. The next most common nutrient acquisition traits in vitro were (in rank order): nitrogen fixation/N-scavenging, phosphate solubilisation, siderophore secretion, and production of ACC deaminase. Secretion of extracellular enzymes required for nutrient acquisition, endophyte colonization and/or community establishment were observed. Bacillus strains had the potential to contribute all tested functional traits to their hosts. CONCLUSION The seeds of economically important cucurbits tested in this study have a culturable core microbiota consisting of Bacillus species with potential to contribute diverse nutrient acquisition and growth promotion activities to their hosts. These microbes may lead to novel seed inoculants to assist sustainable food production. Given that cucurbit seeds are consumed by traditional societies as a source of tryptophan, the precursor for auxin, we discuss the possibility that human selection inadvertently facilitated auxin-mediated increases in gourd size.
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Affiliation(s)
- Eman M Khalaf
- />Department of Plant Agriculture, University of Guelph, Guelph, N1G 2W1 ON Canada
- />Department of Microbiology and Immunology, Faculty of Pharmacy, Damanhour University, Damanhour, Egypt
| | - Manish N Raizada
- />Department of Plant Agriculture, University of Guelph, Guelph, N1G 2W1 ON Canada
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Eevers N, Hawthorne JR, White JC, Vangronsveld J, Weyens N. Exposure of Cucurbita pepo to DDE-contamination alters the endophytic community: A cultivation dependent vs a cultivation independent approach. Environ Pollut 2016; 209:147-54. [PMID: 26683261 DOI: 10.1016/j.envpol.2015.11.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 11/18/2015] [Accepted: 11/22/2015] [Indexed: 05/23/2023]
Abstract
2,2-bis(p-chlorophenyl)-1,1-dichloro-ethylene (DDE) is the most abundant and persistent degradation product of the pesticide 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) and is encountered in contaminated soils worldwide. Both DDE and DDT are classified as Persistent Organic Pollutants (POPs) due to their high hydrophobicity and potential for bioaccumulation and biomagnification in the food chain. Zucchini (Cucurbita pepo ssp. pepo) has been shown to accumulate high concentrations of DDE and other POPs and has been proposed as a phytoremediation tool for contaminated soils. The endophytic bacteria associated with this plant may play an important role in the remedial process. Therefore, this research focuses on changes in endophytic bacterial communities caused by the exposure of C. pepo to DDE. The total bacterial community was investigated using cultivation-independent 454 pyrosequencing, while the cultivable community was identified using cultivation-dependent isolation procedures. For both procedures, increasing numbers of endophytic bacteria, as well as higher diversities of genera were observed when plants were exposed to DDE. Several bacterial genera such as Stenotrophomonas sp. and Sphingomonas sp. showed higher abundance when DDE was present, while, for example Pseudomonas sp. showed a significantly lower abundance in the presence of DDE. These findings suggest tolerance of different bacterial strains to DDE, which might be incorporated in further investigations to optimize phytoremediation with the possible use of DDE-degrading endophytes.
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Affiliation(s)
- N Eevers
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, 3590, Diepenbeek, Belgium
| | - J R Hawthorne
- Connecticut Agricultural Experiment Station, Dept of Analytical Chemistry, 123 Huntington Street, CT 06511, New Haven, USA
| | - J C White
- Connecticut Agricultural Experiment Station, Dept of Analytical Chemistry, 123 Huntington Street, CT 06511, New Haven, USA
| | - J Vangronsveld
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, 3590, Diepenbeek, Belgium.
| | - N Weyens
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, 3590, Diepenbeek, Belgium
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Bellón-Gómez D, Vela-Corcía D, Pérez-García A, Torés JA. Sensitivity of Podosphaera xanthii populations to anti-powdery-mildew fungicides in Spain. Pest Manag Sci 2015; 71:1407-13. [PMID: 25418926 DOI: 10.1002/ps.3943] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 11/12/2014] [Accepted: 11/17/2014] [Indexed: 05/09/2023]
Abstract
BACKGROUND Cucurbit powdery mildew caused by Podosphaera xanthii limits crop production in Spain, where disease control is largely dependent on fungicides. In previous studies, high levels of resistance to QoI and DMI fungicides were documented in south-central Spain. The aim of this study was to investigate the sensitivity of P. xanthii populations to other fungicides and to provide tools for improved disease management. RESULTS Using a leaf-disc assay, sensitivity to thiophanate-methyl, bupirimate and quinoxyfen of 50 isolates of P. xanthii was analysed to determine discriminatory concentrations between sensitive and resistant isolates. With the exception of thiophanate-methyl, no clearly different groups of isolates could be identified, and as a result, discriminatory concentrations were established on the basis of the maximum fungicide field application rate. Subsequently, a survey of P. xanthii resistance to these fungicides was carried out by testing a collection of 237 isolates obtained during the 2002-2011 cucurbit growing seasons. This analysis revealed very high levels of resistance to thiophanate-methyl (95%). By contrast, no resistance to bupirimate and quinoxyfen was found. CONCLUSION Results suggest that thiophanate-methyl has become completely ineffective for controlling cucurbit powdery mildew in Spain. By contrast, bupirimate and quinoxyfen remain as very effective tools for cucurbit powdery mildew management. © 2014 Society of Chemical Industry.
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Affiliation(s)
- Davinia Bellón-Gómez
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental 'La Mayora', Algarrobo-Costa, Málaga, Spain
| | - David Vela-Corcía
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' - Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Málaga, Spain
| | - Alejandro Pérez-García
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' - Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Málaga, Spain
| | - Juan A Torés
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental 'La Mayora', Algarrobo-Costa, Málaga, Spain
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del Agua I, Usack JG, Angenent LT. Comparison of semi-batch vs. continuously fed anaerobic bioreactors for the treatment of a high-strength, solids-rich pumpkin-processing wastewater. Environ Technol 2015; 36:1974-1983. [PMID: 25683478 DOI: 10.1080/09593330.2015.1018842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The objective of this work was to compare two different high-rate anaerobic bioreactor configurations--the anaerobic sequencing batch reactor (ASBR) and the upflow anaerobic solid removal (UASR) reactor--for the treatment of a solid-rich organic wastewater with a high strength. The two, 4.5-L reactors were operated in parallel for close to 100 days under mesophilic conditions (37°C) with non-granular biomass by feeding a pumpkin wastewater with ∼4% solids. The organic loading rate of pumpkin wastewater was increased periodically to a maximum of 8 g COD L(-1) d(-1) by shortening the hydraulic retention time to 5.3 days. Compositional analysis of pumpkin wastewater revealed deficiencies in the trace metal cobalt and alkalinity. With supplementation, the ASBR outperformed the UASR reactor with total chemical oxygen demand (COD) removal efficiencies of 64% and 53%, respectively, achieving a methane yield of 0.27 and 0.20 L CH4 g(-1) COD fed to the ASBR and UASR, respectively. The better performance realized with the ASBR and this specific wastewater was attributed to its semi-batch, dynamic operating conditions rather than the continuous operating conditions of the UASR reactor.
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Affiliation(s)
- Isabel del Agua
- a Department of Biological and Environmental Engineering , Cornell University , Ithaca , NY 14853 , USA
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36
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Brewer MT, Rath M, Li HX. Genetic Diversity and Population Structure of Cucurbit Gummy Stem Blight Fungi Based on Microsatellite Markers. Phytopathology 2015; 105:815-824. [PMID: 25710205 DOI: 10.1094/phyto-10-14-0282-r] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Combining population genetics with epidemiology provides insight into the population biology of pathogens, which could lead to improved management of plant diseases. Gummy stem blight, caused by three closely related species of Stagonosporopsis-Stagonosporopsis cucurbitacearum (syn. Didymella bryoniae), S. citrulli, and S. caricae-is a devastating disease of cucurbits worldwide. Sources of inoculum for epidemics, mechanisms of dispersal, and the mating system of these species are not well understood. To improve our knowledge of gummy stem blight epidemiology, we developed 18 polymorphic microsatellite markers by combining microsatellite motif enrichment with next-generation sequencing. When tested on 46 isolates from diverse cucurbit hosts and regions, the markers were robust for the dominant and widely distributed S. citrulli. Within this species, we found no population structure based on broad-scale geographic region or host of origin. Using the microsatellites, a rapid polymerase chain reaction-based method was developed to distinguish the three morphologically similar species causing gummy stem blight. To better understand dispersal, reproduction, and fine-scale genetic diversity of S. citrulli within and among watermelon fields, 155 isolates from two field populations in Georgia, United States were genotyped with the 18 microsatellite loci. Although dominant and widespread clones were detected, we found relatively high genotypic diversity and recombinant genotypes consistent with outcrossing. Significant population genetic structure between the two field populations demonstrated that there is regional geographic structure and limited dispersal among fields. This study provides insight into the fine-scale genetic diversity and reproductive biology of the gummy stem blight pathogen S. citrulli in the field.
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Affiliation(s)
| | - Manisha Rath
- Department of Plant Pathology, University of Georgia, Athens
| | - Hao-Xi Li
- Department of Plant Pathology, University of Georgia, Athens
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He D, Jian W, Liu X, Shen H, Song S. Synthesis, biological evaluation, and structure-activity relationship study of novel stilbene derivatives as potential fungicidal agents. J Agric Food Chem 2015; 63:1370-7. [PMID: 25594285 DOI: 10.1021/jf5052893] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A total of 22 novel stilbene derivatives containing the 1,3,4-oxadiazole moiety and trimethoxybenzene were designed and synthesized. Their chemical structures were characterized by (1)H and (13)C nuclear magnetic resonance, infrared, and high-resolution mass spectrometry. Bioassay results revealed that some of the title compounds showed potent in vivo fungicidal activities against three phytopathogenic fungi (Pseudoperonospora cubensis, Colletotrichum lagenarium, and Septoria cucurbitacearum) from cucurbits at 600 μg/mL. Notably, compounds 4b, 4d, 4i, 4k, and 4l exhibited a broad spectrum and remarkably high activities against those fungi, some of which even showed a comparable control efficacy to that of the commercial fungicides. Three-dimensional quantitative structure-activity relationship based on comparative molecular field analysis with good predictive ability (q(2) = 0.516; r(2) = 0.920) was reasonably discussed. For the first time, the present work suggested that the stilbene derivatives containing the 1,3,4-oxadiazole moiety could be developed as potential fungicides for crop protection.
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Affiliation(s)
- Daohang He
- School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou, Guangdong 510640, People's Republic of China
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Vela-Corcía D, Romero D, Torés JA, De Vicente A, Pérez-García A. Transient transformation of Podosphaera xanthii by electroporation of conidia. BMC Microbiol 2015. [PMID: 25651833 DOI: 10.1186/s12866-014-0338-338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
BACKGROUND Powdery mildew diseases are a major phytosanitary issue causing important yield and economic losses in agronomic, horticultural and ornamental crops. Powdery mildew fungi are obligate biotrophic parasites unable to grow on culture media, a fact that has significantly limited their genetic manipulation. In this work, we report a protocol based on the electroporation of fungal conidia, for the transient transformation of Podosphaera fusca (synonym Podosphaera xanthii), the main causal agent of cucurbit powdery mildew. RESULTS To introduce DNA into P. xanthii conidia, we applied two square-wave pulses of 1.7 kV for 1 ms with an interval of 5 s. We tested these conditions with several plasmids bearing as selective markers hygromycin B resistance (hph), carbendazim resistance (TUB2) or GFP (gfp) under control of endogenous regulatory elements from Aspergillus nidulans, Neurospora crassa or P. xanthii to drive their expression. An in planta selection procedure using the MBC fungicide carbendazim permitted the propagation of transformants onto zucchini cotyledons and avoided the phytotoxicity associated with hygromycin B. CONCLUSION This is the first report on the transformation of P. xanthii and the transformation of powdery mildew fungi using electroporation. Although the transformants are transient, this represents a feasible method for the genetic manipulation of this important group of plant pathogens.
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Affiliation(s)
- David Vela-Corcía
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de Teatinos), 29071, Málaga, Spain.
| | - Diego Romero
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de Teatinos), 29071, Málaga, Spain.
| | - Juan Antonio Torés
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental "La Mayora", 29750 Algarrobo-Costa, Málaga, Spain.
| | - Antonio De Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de Teatinos), 29071, Málaga, Spain.
| | - Alejandro Pérez-García
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31 (Campus Universitario de Teatinos), 29071, Málaga, Spain.
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39
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Igbeneghu OA, Abdu AB. Multiple antibiotic-resistant bacteria on fluted pumpkin leaves, a herb of therapeutic value. J Health Popul Nutr 2014; 32:176-82. [PMID: 25076655 PMCID: PMC4216954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fluted pumpkin (Telfairia occidentalis) is a minimally-processed green leafy vegetable traditionally used for its antianaemic properties in the form of leaf juice without a heating or inactivation step before consumption. The aim of the study was to assess the presence of surface microbiota on T. occidentalis leaves and also to determine the antimicrobial susceptibility of isolated organisms. Bacterial contaminants on 50 samples of T. occidentalis leaves were isolated and characterized using standard biochemical methods and the antimicrobial susceptibility of isolated organisms was determined using the antibiotic disc diffusion assay. The results obtained show that the leaves of T. occidentalis is contaminated with organisms which included Enterobacter agglomerans (25.9%), Proteus vulgaris (24.9%), Klebsiella spp. (2.6%), and Serratia liquefaciens (2.1%). Other bacterial isolates recovered in order of frequency included: Staphylococcus spp. (33.7%), Bacillus spp. (8.3%), and Pseudomonas fluorescens (2.6%). Of the 193 bacterial isolates from the leaves of T. occidentalis samples tested for antimicrobial resistance, all (100%) were found to be resistant to ampicillin, cloxacillin, augmentin, erythromycin, and tetracycline while 96% of the isolates were resistant to cephalothin. Resistance to trimethoprim (93%) and gentamicin (83%) was also observed. Approximately, 22% of the isolates were resistant to ciprofloxacin; however, only 11 (5.8%) were resistant to ofloxacin. Thus, uncooked T. occidentalis is a potential source of highly-resistant epiphytic bacteria which could be opportunistic pathogens in consumers.
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Affiliation(s)
- Oluwatoyin A. Igbeneghu
- Department of Pharmaceutics, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
| | - Abdulrasheed B. Abdu
- Department of Medical Microbiology and Parasitology, Faculty of Basic Medical Sciences, College of Health Sciences, Niger Delta University, Wilberforce Island, Bayelsa-State, Nigeria
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Zhao YR, Yu KQ, Li XL, He Y. [Study on SPAD visualization of pumpkin leaves based on hyperspectral imaging technology]. Guang Pu Xue Yu Guang Pu Fen Xi 2014; 34:1378-1382. [PMID: 25095442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Visible/near-infrared (380 approximately 1 030 nm) hyperspectral imaging technique was used to realize SPAD visualization of pumpkin leaves in the present study. Downy mildew could be diagnosed rapidly according to significant positive correlation between downy mildew epidemic and chlorophyll content. Leaves uninfected and infected with different level downy mildew were used to acquire hyperspectral images and extract spectral information. Competitive adaptive reweighted sampling (CARS) was applied to select optimal wavelengths and finally 10 optimal wavelengths were obtained. Partial least squares regression (PLSR) was employed to establish SPAD prediction model. Results showed that, through the analysis of calibration of 48 samples and prediction of 23 samples, CARS-PLSR could obtain good results with Rc= 0. 918, RMSECV= 3. 932; Rcv- 0. 846, RMSECV = 5. 254; Rp = 0. 881, and RMSEP= 3. 714. Regression model was gained based on the relationship between SPAD and spectral of pumpkin leaves. While SPAD of each pixel was calculated with PLSR regression equation, then SPAD distribution map of pumpkin was visualized using imaging processing technology. Final downy mildew infection could be diagnosed based on SPAD distribution map. This study provided a theoretical reference for effective monitoring plant growth and downy mildew epidemic.
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Shapiro LR, Seidl-Adams I, De Moraes CM, Stephenson AG, Mescher MC. Dynamics of short- and long-term association between a bacterial plant pathogen and its arthropod vector. Sci Rep 2014; 4:4155. [PMID: 24561664 PMCID: PMC3932477 DOI: 10.1038/srep04155] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 01/31/2014] [Indexed: 11/08/2022] Open
Abstract
The dynamics of association between pathogens and vectors can strongly influence epidemiology. It has been proposed that wilt disease epidemics in cucurbit populations are sustained by persistent colonization of beetle vectors (Acalymma vittatum) by the bacterial phytopathogen Erwinia tracheiphila. We developed a qPCR method to quantify E. tracheiphila in whole beetles and frass and used it to assess pathogen acquisition and retention following variable exposure to infected plants. We found that (i) E. tracheiphila is present in frass in as little as three hours after feeding on infected plants and can be transmitted with no incubation period by vectors given brief exposure to infected plants, but also by persistently colonized vectors several weeks following exposure; (ii) duration of exposure influences rates of long-term colonization; (iii) frass infectivity (assessed via inoculation experiments) reflects bacterial levels in frass samples across time; and (iv) vectors rarely clear E. tracheiphila infections, but suffer no apparent loss of fitness. These results describe a pattern conducive to the effective maintenance of E. tracheiphila within cucurbit populations.
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Affiliation(s)
- L. R. Shapiro
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802
- Department of Organismic and Evolutionary Biology, Harvard University, 02138
| | - I. Seidl-Adams
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802
| | - C. M. De Moraes
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802
- Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - A. G. Stephenson
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
| | - M. C. Mescher
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802
- Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
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Yang R, Meng D, Hu X, Ni Y, Li Q. Saccharification of pumpkin residues by coculturing of Trichoderma reesei RUT-C30 and Phanerochaete chrysosporium Burdsall with delayed inoculation timing. J Agric Food Chem 2013; 61:9192-9. [PMID: 24020787 DOI: 10.1021/jf402199j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Trichoderma reesei and Phanerochaete chrysosporium with different lignocellulose-degrading enzyme systems have received much attention due to their ability to biodegrade lignocellulosic biomass. However, the synergistic effect of the two fungi on lignocellulose degradation is unknown. Herein, a cocultivation of T. reesei RUT-C30 and P. chrysosporium Burdsall for biodegradation of lignocellulosic pumpkin residues (PRS) was developed to produce soluble saccharide. Results indicated that a cocultivation of the two fungi with P. chrysosporium Burdsall inoculation delayed for 1.5 days produced the highest saccharide yield of 53.08% (w/w), and only 20.83% (w/w) of PRS were left after one batch of fermentation. In addition, this strategy increased the activities of secreted cellulases (endoglucanase, cellobiohydrolase, and β-glucosidase) and ligninases (lignin peroxidase and manganese peroxidase), which correlated to the increased saccharide yield. Besides, the resulting monosaccharides including glucose (1.23 mg/mL), xylose (0.13 mg/mL), arabinose (0.46 mg/mL), and fructose (0.21 mg/mL) from cocultures exhibited much higher yields than those from monoculture, which provides basal information for further fermentation research. This bioconversion of PRS into soluble sugars by cocultured fungal species provides a low cost method based on lignocellulose for potential biofuels or other bioproduct production.
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Affiliation(s)
- Rui Yang
- College of Food Science and Nutritional Engineering, China Agricultural University , China Key Laboratory of Fruit and Vegetable Processing, Ministry of Agriculture, China Research Center for Fruit and Vegetable Processing Engineering, Ministry of Education, Beijing 100083, China
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Rojas ES, Dixon PM, Batzer JC, Gleason ML. Genetic and virulence variability among Erwinia tracheiphila strains recovered from different cucurbit hosts. Phytopathology 2013; 103:900-905. [PMID: 23927426 DOI: 10.1094/phyto-11-12-0301-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The causal agent of cucurbit bacterial wilt, Erwinia tracheiphila, has a wide host range in the family Cucurbitaceae, including economically important crops such as muskmelon (Cucumis melo), cucumber (C. sativus), and squash (Cucurbita spp.). Genetic variability of 69 E. tracheiphila strains was investigated by repetitive-element polymerase chain reaction (rep-PCR) using BOXA1R and ERIC1-2 primers. Fingerprint profiles revealed significant variability associated with crop host; strains isolated from Cucumis spp. were clearly distinguishable from Cucurbita spp.-isolated strains regardless of geographic origin. Twelve E. tracheiphila strains isolated from muskmelon, cucumber, or summer squash were inoculated onto muskmelon and summer squash seedlings, followed by incubation in a growth chamber. Wilt symptoms were assessed over 3 weeks, strains were reisolated, and rep-PCR profiles were compared with the inoculated strains. Wilting occurred significantly faster when seedlings were inoculated with strains that originated from the same crop host genus (P<0.001). In the first run of the experiment, cucumber and muskmelon strains caused wilting on muskmelon seedlings at a median of 7.8 and 5.6 days after inoculation (dai), respectively. Summer squash seedlings wilted 18.0, 15.7, and 5.7 dai when inoculated with muskmelon-, cucumber-, and squash-origin strains, respectively. In a second run of the experiment, cucumber and muskmelon strains caused wilting on muskmelon at 7.0 and 6.9 dai, respectively, whereas summer squash seedlings wilted at 23.6, 29.0 and 9.0 dai when inoculated with muskmelon-, cucumber-, and squash-origin strains, respectively. Our results provide the first evidence of genetic diversity within E. tracheiphila and suggest that strain specificity is associated with plant host. This advance is a first step toward understanding the genetic and population structure of E. tracheiphila.
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Affiliation(s)
- E Saalau Rojas
- Department of Plant Pathology and Microbiology, Iowa State University, Ames 50011, USA
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Lamour KH, Mudge J, Gobena D, Hurtado-Gonzales OP, Schmutz J, Kuo A, Miller NA, Rice BJ, Raffaele S, Cano LM, Bharti AK, Donahoo RS, Finley S, Huitema E, Hulvey J, Platt D, Salamov A, Savidor A, Sharma R, Stam R, Storey D, Thines M, Win J, Haas BJ, Dinwiddie DL, Jenkins J, Knight JR, Affourtit JP, Han CS, Chertkov O, Lindquist EA, Detter C, Grigoriev IV, Kamoun S, Kingsmore SF. Genome sequencing and mapping reveal loss of heterozygosity as a mechanism for rapid adaptation in the vegetable pathogen Phytophthora capsici. Mol Plant Microbe Interact 2012; 25:1350-60. [PMID: 22712506 PMCID: PMC3551261 DOI: 10.1094/mpmi-02-12-0028-r] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The oomycete vegetable pathogen Phytophthora capsici has shown remarkable adaptation to fungicides and new hosts. Like other members of this destructive genus, P. capsici has an explosive epidemiology, rapidly producing massive numbers of asexual spores on infected hosts. In addition, P. capsici can remain dormant for years as sexually recombined oospores, making it difficult to produce crops at infested sites, and allowing outcrossing populations to maintain significant genetic variation. Genome sequencing, development of a high-density genetic map, and integrative genomic or genetic characterization of P. capsici field isolates and intercross progeny revealed significant mitotic loss of heterozygosity (LOH) in diverse isolates. LOH was detected in clonally propagated field isolates and sexual progeny, cumulatively affecting >30% of the genome. LOH altered genotypes for more than 11,000 single-nucleotide variant sites and showed a strong association with changes in mating type and pathogenicity. Overall, it appears that LOH may provide a rapid mechanism for fixing alleles and may be an important component of adaptability for P. capsici.
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Ilina EL, Logachov AA, Laplaze L, Demchenko NP, Pawlowski K, Demchenko KN. Composite Cucurbita pepo plants with transgenic roots as a tool to study root development. Ann Bot 2012; 110:479-89. [PMID: 22553131 PMCID: PMC3394650 DOI: 10.1093/aob/mcs086] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 03/05/2012] [Indexed: 05/21/2023]
Abstract
BACKGROUND AND AIMS In most plant species, initiation of lateral root primordia occurs above the elongation zone. However, in cucurbits and some other species, lateral root primordia initiation and development takes place in the apical meristem of the parental root. Composite transgenic plants obtained by Agrobacterium rhizogenes-mediated transformation are known as a suitable model to study root development. The aim of the present study was to establish this transformation technique for squash. METHODS The auxin-responsive promoter DR5 was cloned into the binary vectors pKGW-RR-MGW and pMDC162-GFP. Incorporation of 5-ethynyl-2'-deoxyuridine (EdU) was used to evaluate the presence of DNA-synthesizing cells in the hypocotyl of squash seedlings to find out whether they were suitable for infection. Two A. rhizogenes strains, R1000 and MSU440, were used. Roots containing the respective constructs were selected based on DsRED1 or green fluorescent protein (GFP) fluorescence, and DR5::Egfp-gusA or DR5::gusA insertion, respectively, was verified by PCR. Distribution of the response to auxin was visualized by GFP fluorescence or β-glucuronidase (GUS) activity staining and confirmed by immunolocalization of GFP and GUS proteins, respectively. KEY RESULTS Based on the distribution of EdU-labelled cells, it was determined that 6-day-old squash seedlings were suited for inoculation by A. rhizogenes since their root pericycle and the adjacent layers contain enough proliferating cells. Agrobacterium rhizogenes R1000 proved to be the most virulent strain on squash seedlings. Squash roots containing the respective constructs did not exhibit the hairy root phenotype and were morphologically and structurally similar to wild-type roots. CONCLUSIONS The auxin response pattern in the root apex of squash resembled that in arabidopsis roots. Composite squash plants obtained by A. rhizogenes-mediated transformation are a good tool for the investigation of root apical meristem development and root branching.
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Affiliation(s)
- Elena L. Ilina
- Komarov Botanical Institute, Russian Academy of Sciences, Prof. Popova 2, 197376, St.-Petersburg, Russia
| | - Anton A. Logachov
- Komarov Botanical Institute, Russian Academy of Sciences, Prof. Popova 2, 197376, St.-Petersburg, Russia
| | - Laurent Laplaze
- Institut de Recherche pour le Développement, UMR DIADE (Agro.M/INRA/IRD/UM2), Equipe Rhizogenèse, 911 Avenue Agropolis, F-34394 Montpellier cedex 5, France
| | - Nikolay P. Demchenko
- Komarov Botanical Institute, Russian Academy of Sciences, Prof. Popova 2, 197376, St.-Petersburg, Russia
| | | | - Kirill N. Demchenko
- Komarov Botanical Institute, Russian Academy of Sciences, Prof. Popova 2, 197376, St.-Petersburg, Russia
- For correspondence. E-mail
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Ji P, Koné D, Yin J, Jackson KL, Csinos AS. Soil amendments with Brassica cover crops for management of Phytophthora blight on squash. Pest Manag Sci 2012; 68:639-644. [PMID: 22065491 DOI: 10.1002/ps.2308] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 08/29/2011] [Accepted: 08/29/2011] [Indexed: 05/31/2023]
Abstract
BACKGROUND Phytophthora blight induced by Phytophthora capsici is responsible for serious yield loss in vegetable production in the United States and other countries. This study was conducted to evaluate the efficacy of Brassica cover crops used as soil amendments for managing Phytophthora blight of squash. RESULTS In greenhouse studies, disease incidence on squash plants was significantly reduced by soil amendment with mustard shoots or roots used at 1 and 2.5% (plant tissue/soil, w/w). The shoots of canola used at 1 or 2.5% also suppressed disease, while the roots of canola or other crops did not reduce disease significantly. In field studies, soil amendments with mustard and canola provided the greatest disease reduction and increased squash yield significantly compared with the non-treated control. Mustard and canola did not appear to be susceptible to P. capsici. CONCLUSION The results indicated that some Brassica crops, particularly mustard and canola, had the potential to significantly reduce Phytophthora blight on squash when used as soil amendments. As P. capsici has a remarkable ability to develop resistance to chemical fungicides, use of effective Brassica cover crops could be a biorational alternative to fungicides and a valuable component in developing integrated disease management programs.
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Affiliation(s)
- Pingsheng Ji
- Department of Plant Pathology, Coastal Plain Experiment Station, University of Georgia, Tifton, GA 31794, USA.
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Fürnkranz M, Lukesch B, Müller H, Huss H, Grube M, Berg G. Microbial diversity inside pumpkins: microhabitat-specific communities display a high antagonistic potential against phytopathogens. Microb Ecol 2012; 63:418-28. [PMID: 21947430 DOI: 10.1007/s00248-011-9942-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 09/05/2011] [Indexed: 05/05/2023]
Abstract
Recent and substantial yield losses of Styrian oil pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) are primarily caused by the ascomycetous fungus Didymella bryoniae but bacterial pathogens are frequently involved as well. The diversity of endophytic microbial communities from seeds (spermosphere), roots (endorhiza), flowers (anthosphere), and fruits (carposphere) of three different pumpkin cultivars was studied to develop a biocontrol strategy. A multiphasic approach combining molecular, microscopic, and cultivation techniques was applied to select a consortium of endophytes for biocontrol. Specific community structures for Pseudomonas and Bacillus, two important plant-associated genera, were found for each microenvironment by fingerprinting of 16S ribosomal RNA genes. All microenvironments were dominated by bacteria; fungi were less abundant. Of the 2,320 microbial isolates analyzed in dual culture assays, 165 (7%) were tested positively for in vitro antagonism against D. bryoniae. Out of these, 43 isolates inhibited the growth of bacterial pumpkin pathogens (Pectobacterium carotovorum, Pseudomonas viridiflava, Xanthomonas cucurbitae); here only bacteria were selected. Microenvironment-specific antagonists were found, and the spermosphere and anthosphere were revealed as underexplored reservoirs for antagonists. In the latter, a potential role of pollen grains as bacterial vectors between flowers was recognized. Six broad spectrum antagonists selected according to their activity, genotypic diversity, and occurrence were evaluated under greenhouse conditions. Disease severity on pumpkins of D. bryoniae was significantly reduced by Pseudomonas chlororaphis treatment and by a combined treatment of strains (Lysobacter gummosus, P. chlororaphis, Paenibacillus polymyxa, and Serratia plymuthica). This result provides a promising prospect to biologically control pumpkin diseases.
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Affiliation(s)
- Michael Fürnkranz
- Institute of Environmental Biotechnology, Graz University of Technology, Petersgasse 12, Graz, Austria
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Pugliese M, Alvarez MTM, Gullino ML, Garibaldi A. Effects of silicates from scaps of photovoltaic industries on powdery mildew of zucchini. Commun Agric Appl Biol Sci 2012; 77:75-78. [PMID: 23878962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Silicon is the second most abundant element on earth's surface and its use can stimulate natural defense mechanisms in plants. The effect of silicate from scraps of photovoltaic industries against powdery mildew on zucchini (Cucurbita pepo) was evaluated under greenhouse conditions. Potted plants were inoculated with a spore suspension containing 1 x 10(5) cfu/ml. The following treatments have been carried out, 3 and 10 days after pathogen inoculation: chemical fungicide (propiconazole, TILT 25 EC, Syngenta); Bacillus subtilis (250 g/hl, Serenade, Intrachem); 1% and 0.1% sodium silicate (r = 1); 1% and 0.1% sodium silicate (r = 2); tap water as control. Disease incidence and severity were assessed 7, 14 and 21days after pathogen inoculation. Results showed that the application of 1% sodium silicate (r = 1) significantly reduced the powdery mildew to a level similar to chemical control. The other treatments, including Bacillus subtilis, reduced disease severity compared to water control, but were less efficient. The use of silicates from photovoltaic industries is a valid alternative for the control of powdery mildew on zucchini, in particular in organic farming. However, silicates might not be sufficient at higher disease incidence levels, and their use is more suitable within an integrated disease control strategy.
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Affiliation(s)
- M Pugliese
- University of Torino, Centre of Competence for the Innovation in the agro-environmental field (AGROINNOVA), Via L. da Vinci 44, I-10095 Grugliasco (TO), Italy.
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Tabata J, De Moraes CM, Mescher MC. Olfactory cues from plants infected by powdery mildew guide foraging by a mycophagous ladybird beetle. PLoS One 2011; 6:e23799. [PMID: 21876772 PMCID: PMC3158101 DOI: 10.1371/journal.pone.0023799] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 07/25/2011] [Indexed: 11/19/2022] Open
Abstract
Powdery mildews (Erysiphales) are economically important plant pathogens that attack many agricultural crops. Conventional management strategies involving fungicide application face challenges, including the evolution of resistance and concerns over impacts on non-target organisms, that call for investigation of more sustainable alternatives. Mycophagous ladybird beetles (Coleoptera: Coccinellidae) feed on powdery mildew and have considerable potential as biological control agents; however, the foraging ecology and behavior of these beetles is not well understood. Here we document the olfactory cues presented by squash plants (Cucurbita moschata) infected by powdery mildew (Podosphaera sp.) and the behavioral responses of twenty-spotted ladybird beetles (Psyllobora vigintimaculata) to these cues. Volatile analyses through gas chromatography revealed a number of volatile compounds characteristic of infected plants, including 3-octanol and its analogues 1-octen-3-ol and 3-octanone. These compounds are typical "moldy" odorants previously reported in volatiles collected from other fungi. In addition, infected plants exhibited elevated emissions of several compounds also observed in collections from healthy leaves, including linalool and benzyl alcohol, which are reported to have anti-fungal properties. In Y-tube choice assays, P. vigintimaculata beetles displayed a significant preference for the odors of infected plants compared to those of healthy plants. Moreover, beetles exhibited strong attraction to one individual compound, 1-octen-3-ol, which was the most abundant of the characteristic fungal compounds identified. These results enhance our understanding of the olfactory cues that guide foraging by mycophagous insects and may facilitate the development of integrated disease-management strategies informed by an understanding of underlying ecological mechanisms.
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Affiliation(s)
- Jun Tabata
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Biodiversity Division, National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki Prefecture, Japan
| | - Consuelo M. De Moraes
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Mark C. Mescher
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
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Abstract
A meta-analysis of the effect of fungicides on cucurbit downy mildew was conducted using data previously published in Fungicide & Nematicide Tests and Plant Disease Management Reports from 2000 to 2008. Standardized mean effect size (the difference in disease intensity expressed in standard deviation units between the fungicide treatment and its corresponding untreated control) was calculated for each of the 105 field studies evaluating the effects of fungicides on cucurbit downy mildew. Fixed- and random-effects meta-analyses were performed on the log-transformed standardized mean effect sizes to estimate the overall mean effect size (L+), and to determine the variability in the effect size among studies. Fungicides led to a significant (P<0.001) reduction in disease with an L+ value of 1.198, indicating that, overall, fungicides were highly effective against cucurbit downy mildew. Fixed- and random-effects meta-analyses were then conducted to determine the effects of moderator variables on L+. The fixed-effects model resulted in narrower 95% confidence intervals and generally lower estimates of moderator subgroup mean effect size (L) than the random-effects models. Fungicide efficacy was significantly (P<0.001) greater in cucumber, with L being 26.5% higher in cucumber than in other cucurbits. Year of study, number of sprays, and disease pressure in the control significantly (P<0.001) affected L. Fungicide efficacy was significantly lower during the 2004-05 season than prior to or after the 2004-05 season. Studies in which disease pressure was moderate had a significantly higher L than studies with either low or high disease pressure. Fungicide efficacy was ≥22% in studies that received 5 to 6 sprays than in studies that received 1 to 4 or >6 sprays. Fungicide products led to a significant (P<0.001) reduction in disease, although there was substantial between-study variability. The pyridinylmethyl-benzamide group of fungicides (fluopicolide) was the most effective, followed by the carbamate (propamocarb) and quinone inside inhibitors (cyazofamid) group of fungicides, while the carboxylic acid amide group (mandipropamid and dimethomorph) was the least effective. A combination of protectant and systemic fungicides resulted in a proportional increase in L compared with sole application of either protectant or systemic fungicides.
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Affiliation(s)
- P S Ojiambo
- Department of Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA.
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