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Gfeller A, Fuchsmann P, De Vrieze M, Gindro K, Weisskopf L. Bacterial Volatiles Known to Inhibit Phytophthora infestans Are Emitted on Potato Leaves by Pseudomonas Strains. Microorganisms 2022; 10:microorganisms10081510. [PMID: 35893568 PMCID: PMC9394277 DOI: 10.3390/microorganisms10081510] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/24/2022] [Accepted: 07/05/2022] [Indexed: 11/29/2022] Open
Abstract
Bacterial volatiles play important roles in mediating beneficial interactions between plants and their associated microbiota. Despite their relevance, bacterial volatiles are mostly studied under laboratory conditions, although these strongly differ from the natural environment bacteria encounter when colonizing plant roots or shoots. In this work, we ask the question whether plant-associated bacteria also emit bioactive volatiles when growing on plant leaves rather than on artificial media. Using four potato-associated Pseudomonas, we demonstrate that potato leaves offer sufficient nutrients for the four strains to grow and emit volatiles, among which 1-undecene and Sulfur compounds have previously demonstrated the ability to inhibit the development of the oomycete Phytophthora infestans, the causative agent of potato late blight. Our results bring the proof of concept that bacterial volatiles with known plant health-promoting properties can be emitted on the surface of leaves and warrant further studies to test the bacterial emission of bioactive volatiles in greenhouse and field-grown plants.
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Affiliation(s)
- Aurélie Gfeller
- Changins School of Viticulture and Oenology, 1260 Nyon, Switzerland; (A.G.); (M.D.V.)
- Agroscope, Plant Protection, 1260 Nyon, Switzerland;
| | - Pascal Fuchsmann
- Agroscope, Nutrition, Sensory analysis and Flavour Group, 3003 Bern, Switzerland;
| | - Mout De Vrieze
- Changins School of Viticulture and Oenology, 1260 Nyon, Switzerland; (A.G.); (M.D.V.)
- Agroscope, Plant Protection, 1260 Nyon, Switzerland;
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Katia Gindro
- Agroscope, Plant Protection, 1260 Nyon, Switzerland;
| | - Laure Weisskopf
- Changins School of Viticulture and Oenology, 1260 Nyon, Switzerland; (A.G.); (M.D.V.)
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
- Correspondence:
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González-Tobón J, Childers RR, Rodríguez A, Fry W, Myers KL, Thompson JR, Restrepo S, Danies G. Searching for the Mechanism that Mediates Mefenoxam-Acquired Resistance in Phytophthora infestans and How It Is Regulated. PHYTOPATHOLOGY 2022; 112:1118-1133. [PMID: 34763530 DOI: 10.1094/phyto-07-21-0280-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Phytophthora infestans, the causal agent of late blight disease of potatoes, is mainly controlled by the use of fungicides. Isolates that are resistant to commonly used fungicides have been reported. Also, several studies show that originally mefenoxam-sensitive isolates acquire resistance to this fungicide when exposed to sublethal concentrations. This phenomenon, termed "mefenoxam-acquired resistance," has been observed in different Phytophthora species and seems to be unique to mefenoxam. In this study, we aimed to elucidate the molecular mechanism mediating this type of resistance as well as a possible regulatory process behind it. A combination of computational analyses and experimental approaches was used to identify differentially expressed genes with a potential association to the phenomenon. These genes were classified into seven functional groups. Most of them seem to be associated with a pleiotropic drug resistance (PDR) phenotype, typically involved in the expulsion of diverse metabolites, drugs, or other substances out of the cell. Despite the importance of RNA Polymerase I for the constitutive resistance of P. infestans to mefenoxam, our results indicate no clear interaction between this protein and the acquisition of mefenoxam resistance. Several small non-coding RNAs were found to be differentially expressed and specifically related to genes mediating the PDR phenotype, thus suggesting a possible regulatory process. We propose a model of the molecular mechanisms acting within the cell when P. infestans acquires resistance to mefenoxam after exposed to sublethal concentrations of the fungicide. This study provides important insights into P. infestans' cellular and regulatory functionalities.
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Affiliation(s)
- Juliana González-Tobón
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia 111711
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY 14853, U.S.A
| | | | - Alejandra Rodríguez
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia 111711
| | - William Fry
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY 14853, U.S.A
| | - Kevin L Myers
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY 14853, U.S.A
| | - Jeremy R Thompson
- Plant Health and Environment Laboratory, Ministry for Primary Industries, Auckland 1072, New Zealand
| | - Silvia Restrepo
- Department of Food and Chemical Engineering, Universidad de los Andes, Bogotá, Colombia 111711
| | - Giovanna Danies
- Department of Design, Universidad de los Andes, Bogotá, Colombia 111711
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Ayala-Usma DA, Danies G, Myers K, Bond MO, Romero-Navarro JA, Judelson HS, Restrepo S, Fry WE. Genome-Wide Association Study Identifies Single Nucleotide Polymorphism Markers Associated with Mycelial Growth (at 15, 20, and 25°C), Mefenoxam Resistance, and Mating Type in Phytophthora infestans. PHYTOPATHOLOGY 2020; 110:822-833. [PMID: 31829117 DOI: 10.1094/phyto-06-19-0206-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Phenotypic diversity among individuals defines the potential for evolutionary selection in a species. Phytophthora infestans epidemics are generally thought to be favored by moderate to low temperatures, but temperatures in many locations worldwide are expected to rise as a result of global climate change. Thus, we investigated variation among individuals of P. infestans for relative growth at different temperatures. Isolates of P. infestans came from three collections: (i) individual genotypes recently dominant in the United States, (ii) recently collected individuals from Central Mexico, and (iii) progeny of a recent sexual recombination event in the northeastern United States. In general, these isolates had optimal mycelial growth rates at 15 or 20°C. However, two individuals from Central Mexico grew better at higher temperatures than did most others and two individuals grew relatively less at higher temperatures than did most others. The isolates were also assessed for mefenoxam sensitivity and mating type. Each collection contained individuals of diverse sensitivities to mefenoxam and individuals of the A1 and A2 mating type. We then searched for genomic regions associated with phenotypic diversity using genotyping-by-sequencing. We found one single nucleotide polymorphism (SNP) associated with variability in mycelial growth at 20°C, two associated with variability in mycelial growth at 25°C, two associated with sensitivity to mefenoxam, and one associated with mating type. Interestingly, the SNPs associated with mefenoxam sensitivity were found in a gene-sparse region, whereas the SNPs associated with growth at the two temperatures and mating type were found both at more gene-dense regions.
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Affiliation(s)
- D A Ayala-Usma
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
- Max Planck Tandem Group in Computational Biology, Universidad de los Andes, Bogotá, Colombia
| | - G Danies
- Department of Design, Universidad de los Andes, Bogotá, Colombia
| | - K Myers
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, U.S.A
| | - M O Bond
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, U.S.A
- Department of Botany, University of Hawaii, Mānoa, HI, U.S.A
| | - J A Romero-Navarro
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, U.S.A
| | - H S Judelson
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, U.S.A
| | - S Restrepo
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - W E Fry
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, U.S.A
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González-Tobón J, Childers R, Olave C, Regnier M, Rodríguez-Jaramillo A, Fry W, Restrepo S, Danies G. Is the Phenomenon of Mefenoxam-Acquired Resistance in Phytophthora infestans Universal? PLANT DISEASE 2020; 104:211-221. [PMID: 31765279 DOI: 10.1094/pdis-10-18-1906-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Phytophthora infestans is the causal agent of late blight disease of potatoes and tomatoes. This disease causes devastating economic losses each year, and control is mainly achieved by the use of fungicides. Unfortunately, populations of P. infestans resistant to fungicides have been documented. Furthermore, studies have reported that sensitive isolates to the phenylamide fungicide, mefenoxam, become less sensitive in vitro after a single passage through sublethal concentrations of fungicide-amended medium. The first objective of this study was to investigate if isolates of P. infestans are capable of acquiring resistance to two additional systemic fungicides, fluopicolide (benzamide) and cymoxanil (cyanoacetamide-oxime). In contrast to the situation with mefenoxam, exposure of isolates to sublethal concentrations of fluopicolide and cymoxanil did not induce reduced sensitivity to these two fungicides. The second objective was to assess if reduced sensitivity to mefenoxam could occur in naturally sensitive isolates of other Phytophthora species and of Phytopythium sp., another oomycete plant pathogen. All Phytophthora spp. assessed (P. infestans, P. betacei, and P. pseudocryptogea) as well as Phytopythium sp. acquired resistance to mefenoxam after previous exposure through medium containing 1 µg ml-1 of mefenoxam. Interestingly, isolate 66 of Phytopythium sp. and the isolate of P. pseudocryptogea tested do not seem to be acquiring resistance to mefenoxam after exposure to medium containing 5 µg ml-1 of this fungicide. The tested isolates of P. palmivora and P. cinnamomi were extremely sensitive to mefenoxam, and thus it was not possible to perform a second transfer to access acquisition of resistance to this fungicide.
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Affiliation(s)
| | - Richard Childers
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, U.S.A
| | - Carolina Olave
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Melissa Regnier
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | | | - William Fry
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY, U.S.A
| | - Silvia Restrepo
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Giovanna Danies
- Department of Design, Universidad de los Andes, Bogotá, Colombia
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5
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Hansen ZR, Everts KL, Fry WE, Gevens AJ, Grünwald NJ, Gugino BK, Johnson DA, Johnson SB, Judelson HS, Knaus BJ, McGrath MT, Myers KL, Ristaino JB, Roberts PD, Secor GA, Smart CD. Genetic Variation within Clonal Lineages of Phytophthora infestans Revealed through Genotyping-By-Sequencing, and Implications for Late Blight Epidemiology. PLoS One 2016; 11:e0165690. [PMID: 27812174 PMCID: PMC5094694 DOI: 10.1371/journal.pone.0165690] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 10/17/2016] [Indexed: 01/24/2023] Open
Abstract
Genotyping-by-sequencing (GBS) was performed on 257 Phytophthora infestans isolates belonging to four clonal lineages to study within-lineage diversity. The four lineages used in the study were US-8 (n = 28), US-11 (n = 27), US-23 (n = 166), and US-24 (n = 36), with isolates originating from 23 of the United States and Ontario, Canada. The majority of isolates were collected between 2010 and 2014 (94%), with the remaining isolates collected from 1994 to 2009, and 2015. Between 3,774 and 5,070 single-nucleotide polymorphisms (SNPs) were identified within each lineage and were used to investigate relationships among individuals. K-means hierarchical clustering revealed three clusters within lineage US-23, with US-23 isolates clustering more by collection year than by geographic origin. K-means hierarchical clustering did not reveal significant clustering within the smaller US-8, US-11, and US-24 data sets. Neighbor-joining (NJ) trees were also constructed for each lineage. All four NJ trees revealed evidence for pathogen dispersal and overwintering within regions, as well as long-distance pathogen transport across regions. In the US-23 NJ tree, grouping by year was more prominent than grouping by region, which indicates the importance of long-distance pathogen transport as a source of initial late blight inoculum. Our results support previous studies that found significant genetic diversity within clonal lineages of P. infestans and show that GBS offers sufficiently high resolution to detect sub-structuring within clonal populations.
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Affiliation(s)
- Zachariah R. Hansen
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Geneva, NY, United States of America
| | - Kathryne L. Everts
- Department of Plant Science and Landscape Architecture, University of Maryland, Salisbury, MD, United States of America
| | - William E. Fry
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY, United States of America
| | - Amanda J. Gevens
- Department of Plant Pathology, University of Wisconsin, Madison, WI, United States of America
| | - Niklaus J. Grünwald
- Horticultural Crops Research Laboratory, United States Department of Agriculture–Agricultural Research Service, Corvallis, OR, United States of America
| | - Beth K. Gugino
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA, United States of America
| | - Dennis A. Johnson
- Department of Plant Pathology, Washington State University, Pullman, WA, United States of America
| | - Steven B. Johnson
- University of Maine Cooperative Extension, Presque Isle, ME, United States of America
| | - Howard S. Judelson
- Department of Plant Pathology and Microbiology, University of California Riverside, Riverside, CA, United States of America
| | - Brian J. Knaus
- Horticultural Crops Research Laboratory, United States Department of Agriculture–Agricultural Research Service, Corvallis, OR, United States of America
| | - Margaret T. McGrath
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Riverhead, NY, United States of America
| | - Kevin L. Myers
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY, United States of America
| | - Jean B. Ristaino
- Department of Plant Pathology, North Carolina State University, Raleigh, NC, United States of America
| | - Pamela D. Roberts
- Department of Plant Pathology, University of Florida, Immokalee, FL, United States of America
| | - Gary A. Secor
- Department of Plant Pathology, North Dakota State University, Fargo, ND, United States of America
| | - Christine D. Smart
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Geneva, NY, United States of America
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Hansen ZR, Knaus BJ, Tabima JF, Press CM, Judelson HS, Grünwald NJ, Smart CD. SNP-Based Differentiation of Phytophthora infestans Clonal Lineages Using Locked Nucleic Acid Probes and High-Resolution Melt Analysis. PLANT DISEASE 2016; 100:1297-1306. [PMID: 30686206 DOI: 10.1094/pdis-11-15-1247-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Phytophthora infestans, the cause of the devastating late blight disease of potato and tomato, exhibits a clonal reproductive lifestyle in North America. Phenotypes such as fungicide sensitivity and host preference are conserved among individuals within clonal lineages, while substantial phenotypic differences can exist between lineages. Whole P. infestans genomes were aligned and single nucleotide polymorphisms (SNPs) identified as targets for the development of clonal-lineage-specific molecular diagnostic tools. Informative SNPs were used to develop high-resolution melt (HRM) assays and locked nucleic acid (LNA) probes to differentiate lineage US-23, the predominant lineage in the Eastern United States for the past several years, from three other U.S. lineages. Three different primer pairs targeting one to three SNPs were capable of separating lineage US-23 from lineages US-8, US-11, and US-24 using HRM analysis. A fourth HRM primer pair targeted a highly variable genomic region containing nine polymorphisms within 63 bp. These primers separated US-23, US-11, and US-8 plus US-24 into three separate groups following HRM analysis but did not separate US-8 from US-24. Additionally, two LNA probes were designed to target a portion of the P. infestans genome containing two SNPs diagnostic for US-23. A single multiplex quantitative polymerase chain reaction assay containing both differentially labeled LNA probes differentiated individuals belonging to lineage US-23 from those belonging to US-8, US-11, and US-24.
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Affiliation(s)
- Zachariah R Hansen
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, NYSAES, Geneva, NY, 14456
| | - Brian J Knaus
- Horticultural Crops Research Laboratory, United States Department of Agriculture-Agricultural Research Service, (USDA-ARS) Corvallis, OR, 97331
| | - Javier F Tabima
- Botany and Plant Pathology, Oregon State University, Corvallis, 97331
| | | | - Howard S Judelson
- Department of Plant Pathology and Microbiology, University of California, Riverside, 92521
| | - Niklaus J Grünwald
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University; Horticultural Crops Research Laboratory, USDA-ARS; and Botany and Plant Pathology, Oregon State University
| | - Christine D Smart
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University
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Hansen ZR, Knaus BJ, Tabima JF, Press CM, Judelson HS, Grünwald NJ, Smart CD. Loop-mediated isothermal amplification for detection of the tomato and potato late blight pathogen, Phytophthora infestans. J Appl Microbiol 2016; 120:1010-20. [PMID: 26820117 DOI: 10.1111/jam.13079] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 12/01/2022]
Abstract
AIMS To design and validate a colorimetric loop-mediated isothermal amplification assay for rapid detection of Phytophthora infestans DNA. METHODS AND RESULTS Two sets of loop-mediated isothermal amplification (LAMP) primers were designed and evaluated for their sensitivity and specificity for P. infestans. ITSII primers targeted a portion of the internal transcribed spacer region of ribosomal DNA. These primers had a limit of detection of 2 pg P. infestans DNA and cross-reacted with the closely related species Phytophthora nicotianae. Rgn86_2 primers, designed to improve assay specificity, targeted a portion of a conserved hypothetical protein. These primers had a limit of detection of 200 pg P. infestans DNA and did not cross-react with P. nicotianae. The specificity of the Rgn86_2 assay was tested further using the closely related species P. andina, P. ipomoeae, P. mirabilis and P. phaseoli. Cross-reactions occurred with P. andina and P. mirabilis, but neither species occurs on tomato or potato. Both primer sets were able to detect P. infestans DNA extracted from tomato late blight leaf lesions. CONCLUSIONS Two colorimetric LAMP assays detected P. infestans DNA from pure cultures as well as infected leaf tissue. The ITSII primers had higher sensitivity, and the Rgn86_2 primers had higher specificity. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first report of a LAMP assay for the detection of P. infestans, the causal organism of potato and tomato late blight. These assays have potential for immediate utility in plant disease research and diagnostic laboratories.
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Affiliation(s)
- Z R Hansen
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY, USA
| | - B J Knaus
- Horticultural Crops Research Laboratory, USDA Agricultural Research Service, Corvallis, OR, USA
| | - J F Tabima
- Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - C M Press
- Horticultural Crops Research Laboratory, USDA Agricultural Research Service, Corvallis, OR, USA
| | - H S Judelson
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, USA
| | - N J Grünwald
- Horticultural Crops Research Laboratory, USDA Agricultural Research Service, Corvallis, OR, USA.,Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - C D Smart
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY, USA
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Lione G, Gonthier P. A Permutation-Randomization Approach to Test the Spatial Distribution of Plant Diseases. PHYTOPATHOLOGY 2016; 106:19-28. [PMID: 26467780 DOI: 10.1094/phyto-05-15-0112-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The analysis of the spatial distribution of plant diseases requires the availability of trustworthy geostatistical methods. The mean distance tests (MDT) are here proposed as a series of permutation and randomization tests to assess the spatial distribution of plant diseases when the variable of phytopathological interest is categorical. A user-friendly software to perform the tests is provided. Estimates of power and type I error, obtained with Monte Carlo simulations, showed the reliability of the MDT (power > 0.80; type I error < 0.05). A biological validation on the spatial distribution of spores of two fungal pathogens causing root rot on conifers was successfully performed by verifying the consistency between the MDT responses and previously published data. An application of the MDT was carried out to analyze the relation between the plantation density and the distribution of the infection of Gnomoniopsis castanea, an emerging fungal pathogen causing nut rot on sweet chestnut. Trees carrying nuts infected by the pathogen were randomly distributed in areas with different plantation densities, suggesting that the distribution of G. castanea was not related to the plantation density. The MDT could be used to analyze the spatial distribution of plant diseases both in agricultural and natural ecosystems.
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Affiliation(s)
- G Lione
- Department of Agricultural, Forest and Food Sciences, University of Torino, Largo P. Braccini 2, 10095 Grugliasco, Italy
| | - P Gonthier
- Department of Agricultural, Forest and Food Sciences, University of Torino, Largo P. Braccini 2, 10095 Grugliasco, Italy
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Danies G, Myers K, Mideros MF, Restrepo S, Martin FN, Cooke DEL, Smart CD, Ristaino JB, Seaman AJ, Gugino BK, Grünwald NJ, Fry WE. An ephemeral sexual population of Phytophthora infestans in the Northeastern United States and Canada. PLoS One 2014; 9:e116354. [PMID: 25551215 PMCID: PMC4281225 DOI: 10.1371/journal.pone.0116354] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/08/2014] [Indexed: 12/02/2022] Open
Abstract
Phytophthora infestans, the causal agent of late blight disease, has been reported in North America since the mid-nineteenth century. In the United States the lack of or very limited sexual reproduction has resulted in largely clonal populations of P. infestans. In 2010 and 2011, but not in 2012 or 2013, 20 rare and diverse genotypes of P. infestans were detected in a region that centered around central New York State. The ratio of A1 to A2 mating types among these genotypes was close to the 50∶50 ratio expected for sexual recombination. These genotypes were diverse at the glucose-6-phosphate isomerase locus, differed in their microsatellite profiles, showed different banding patterns in a restriction fragment length polymorphism assay using a moderately repetitive and highly polymorphic probe (RG57), were polymorphic for four different nuclear genes and differed in their sensitivity to the systemic fungicide mefenoxam. The null hypothesis of linkage equilibrium was not rejected, which suggests the population could be sexual. These new genotypes were monomorphic in their mitochondrial haplotype that was the same as US-22. Through parentage exclusion testing using microsatellite data and sequences of four nuclear genes, recent dominant lineages US-8, US-11, US-23, and US-24 were excluded as possible parents for these genotypes. Further analyses indicated that US-22 could not be eliminated as a possible parent for 14 of the 20 genotypes. We conclude that US-22 could be a parent of some, but not all, of the new genotypes found in 2010 and 2011. There were at least two other parents for this population and the genotypic characteristics of the other parents were identified.
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Affiliation(s)
- Giovanna Danies
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, New York, United States of America
| | - Kevin Myers
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, New York, United States of America
| | - María F. Mideros
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Silvia Restrepo
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Frank N. Martin
- United States Department of Agriculture – Agriculture Research Services (USDA-ARS), Salinas, California, United States of America
| | | | - Christine D. Smart
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, New York, United States of America
| | - Jean B. Ristaino
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Abby J. Seaman
- New York State Integrated Pest Management Program, Cornell Cooperative Extension, Geneva, New York, United States of America
| | - Beth K. Gugino
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Niklaus J. Grünwald
- Horticultural Crops Research Laboratory, USDA Agricultural Research Service, Corvallis, Oregon, United States of America
- Department of Botany & Pant pathology and Center for Genome Biology and Biocomputing, Oregon State University, Corvallis, Oregon, United States of America
| | - William E. Fry
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, New York, United States of America
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10
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Danies G, Small IM, Myers K, Childers R, Fry WE. Phenotypic Characterization of Recent Clonal Lineages of Phytophthora infestans in the United States. PLANT DISEASE 2013; 97:873-881. [PMID: 30722527 DOI: 10.1094/pdis-07-12-0682-re] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Phytophthora infestans, the causal agent of late blight disease, has been reported in the United States and Canada since the mid-nineteenth century. Due to the lack of or very limited sexual reproduction, the populations of P. infestans in the United States are primarily reproducing asexually and, thus, show a simple genetic structure. The emergence of new clonal lineages of P. infestans (US-22, US-23, and US-24) responsible for the late blight epidemics in the northeastern region of the United States in the summers of 2009 and 2010 stimulated an investigation into phenotypic traits associated with these genotypes. Mating type, differences in sensitivity to mefenoxam, differences in pathogenicity on potato and tomato, and differences in rate of germination were studied for clonal lineages US-8, US-22, US-23, and US-24. Both A1 and A2 mating types were detected. Lineages US-22, US-23, and US-24 were generally sensitive to mefenoxam while US-8 was resistant. US-8 and US-24 were primarily pathogenic on potato while US-22 and US-23 were pathogenic on both potato and tomato. Indirect germination was favored at lower temperatures (5 and 10°C) whereas direct germination, though uncommon, was favored at higher temperatures (20 and 25°C). Sporangia of US-24 released zoospores more rapidly than did sporangia of US-22 and US-23. The association of characteristic phenotypic traits with genotype enables the prediction of phenotypic traits from rapid genotypic analyses for improved disease management.
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Affiliation(s)
- G Danies
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853
| | - I M Small
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853
| | - K Myers
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853
| | - R Childers
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853
| | - W E Fry
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853
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Nagy ZÁ, J. Bakonyi J, Som V, Érsek T. Genetic Diversity of the Population of Phytophthora infestans in Hungary. ACTA ACUST UNITED AC 2006. [DOI: 10.1556/aphyt.41.2006.1-2.6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Wu BM, Subbarao KV, van Bruggen AHC. Analyses of the Relationships Between Lettuce Downy Mildew and Weather Variables Using Geographic Information System Techniques. PLANT DISEASE 2005; 89:90-96. [PMID: 30795289 DOI: 10.1094/pd-89-0090] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Previous studies in coastal California suggested that morning leaf wetness duration and temperature immediately after the prolonged leaf wetness period affect infection of lettuce by the downy mildew pathogen, Bremia lactucae. In this study, spatial analysis tools in a geographic information system were used to interpolate disease assessment data and then relate them to weather variables measured in 1995 and 1997 at weather stations in the Salinas Valley. Among the variables monitored at these weather stations, midday temperature (10:00 A.M. to 2:00 P.M.) was related most strongly to the interpolated downy mildew incidence in a circular area (radius = 5 km) around each station (r = 0.52, P < 0.0001); the higher the midday temperature, the lower the disease incidence. High humidity and prolonged morning leaf wetness duration also were associated with high downy mildew incidence. Cluster analysis resulted in distinct regions with different midday temperatures, which overlapped well (92.2% of the total area) with regions distinguished in previous cluster analyses of downy mildew incidence. Clusters of morning relative humidity showed similar patterns, although they overlapped less well with clusters of disease incidence. These results confirmed that midday temperature is an important determining factor for lettuce downy mildew, and its effects should be incorporated into a disease warning system for coastal California. Cluster analyses based on the effects of temperature have great potential for use in regional downy mildew risk assessment.
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Affiliation(s)
- B M Wu
- Department of Plant Pathology, University of California, Davis, c/o United States Agricultural Research Station, Salinas, CA 93905
| | - K V Subbarao
- Department of Plant Pathology, University of California, Davis, c/o United States Agricultural Research Station, Salinas, CA 93905
| | - A H C van Bruggen
- Biological Farming Systems, Wageningen University and Research Centre, The Netherlands
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Petrzelová I, Lebeda A. Distribution of Compatibility Types and Occurrence of Sexual Reproduction in Natural Populations of Bremia lactucae on Wild Lactuca serriola plants. ACTA ACUST UNITED AC 2003. [DOI: 10.1556/aphyt.38.2003.1-2.6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Cohen Y. Populations of Phytophthora infestans in Israel Underwent Three Major Genetic Changes During 1983 to 2000. PHYTOPATHOLOGY 2002; 92:300-307. [PMID: 18944003 DOI: 10.1094/phyto.2002.92.3.300] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT In this survey, 799 isolates of Phytophthora infestans collected from potato crops in Israel during 1983 to 2000 were analyzed for mating type and sensitivity to metalaxyl, and 324 were analyzed for race structure. The A(2) mating type, first recorded in 1983, fully dominated the pathogen population from 1983 until 1991 (9 years). It was thereafter replaced by the A(1) mating type, which dominated the population during 1993 to 2000. Metalaxyl-resistant isolates were first recorded in 1982. During 1983 to 1991, the majority of the isolates were resistant. Isolates with intermediate sensitivity (I) to this fungicide were first observed in 1993, when both A(1) and A(2) mating types occurred in the population. The proportion of I isolates gradually increased, reaching 39 to 41% in 1997 to 1998, and then declined to approximately 15% in 1999 to 2000. Pathogenicity to nine potato differential cultivars was determined for 80 potato isolates collected in 1983 to 1991, to 11 potato differentials in 173 isolates collected in 1993 to 1998, and in 71 potato isolates collected in 1999 to 2000. The first population was composed of 5 races with race 1,3,4,7,8,10 predominating (76%), the second population was composed of 19 races with race 1,3,4,7,8,10,11 predominating (63%), and the third population exhibited 42 (34 new) races with no single predominating race. RG-57 DNA fingerprinting and allozymes loci assays of 23 isolates revealed that isolates collected during 1984 to 1986 belonged to the PO-57 lineage, whereas those collected during 1997 to 1999 belonged to the RFO-39 lineage. Among isolates collected during 1993 to 1995, two unreported DNA fingerprinting patterns were found. Severe late blight epidemics occurred in tomato crops during 1998 to 2000. Of 35 tomato isolates, 28 were A(1) and only 7 were A(2). Of these tomato isolates, 94% were sensitive to metalaxyl. Almost every isolate had a different race structure on the 11 potato differentials. When inoculated onto three tomato differential cultivars, tomato isolates showed a virulence much more enhanced than potato isolates. The data suggest the Israeli population of P. infestans has passed through three major genetic changes during the past 18 years: in 1983, 1993, and 1999. The recent change included host specialization to tomato.
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Jaime-Garcia R, Orum TV, Felix-Gastelum R, Trinidad-Correa R, Vanetten HD, Nelson MR. Spatial Analysis of Phytophthora infestans Genotypes and Late Blight Severity on Tomato and Potato in the Del Fuerte Valley Using Geostatistics and Geographic Information Systems. PHYTOPATHOLOGY 2001; 91:1156-1165. [PMID: 18943330 DOI: 10.1094/phyto.2001.91.12.1156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
ABSTRACT Genetic structure of Phytophthora infestans, the causal agent of potato and tomato late blight, was analyzed spatially in a mixed potato and tomato production area in the Del Fuerte Valley, Sinaloa, Mexico. Isolates of P. infestans were characterized by mating type, allozyme analysis at the glucose-6-phosphate isomerase and peptidase loci, restriction fragment length polymorphism with probe RG57, metalaxyl sensitivity, and aggressiveness to tomato and potato. Spatial patterns of P. infestans genotypes were analyzed by geographical information systems and geo-statistics during the seasons of 1994-95, 1995-96, and 1996-97. Spatial analysis of the genetic structure of P. infestans indicates that geographic substructuring of this pathogen occurs in this area. Maps displaying the probabilities of occurrence of mating types and genotypes of P. infestans, and of disease severity at a regional scale, were presented. Some genotypes that exhibited differences in epidemiologically important features such as metalaxyl sensitivity and aggressiveness to tomato and potato had a restricted spread and were localized in isolated areas. Analysis of late blight severity showed recurring patterns, such as the earliest onset of the disease in the area where both potato and tomato were growing, strengthening the hypothesis that infected potato tubers are the main source of primary inoculum. The information that geostatistical analysis provides might help improve management programs for late blight in the Del Fuerte Valley.
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Rubin E, Baider A, Cohen Y. Phytophthora infestans Produces Oospores in Fruits and Seeds of Tomato. PHYTOPATHOLOGY 2001; 91:1074-1080. [PMID: 18943443 DOI: 10.1094/phyto.2001.91.11.1074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
ABSTRACT Tomato fruits at the mature green stage coinoculated with A1 + A2 sporangia of Phytophthora infestans, the late blight causal fungus, showed abundant oospores in the vascular tissues, pericarp, columella, and placenta. Oospores were also formed on the surface of fruits kept in moisture-saturated atmosphere. Occasionally, oospores were enclosed between the epidermal hairs of the seed coat. In a few seeds, oospores were detected inside the embryo. The data suggest that blighted tomato fruits may carry a large number of oospores, thus making them a threatening source of blight inoculum. Such fruits may also release airborne oosporic inoculum that may introduce recombinant genotypes within a growing season. Although Phytophthora infestans is seedborne in tomato, to our knowledge, this is the first report on the occurrence of oospores in tomato seeds. Whether such tomato seeds produce blighted seedlings remains to be shown.
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