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Zhang J, Gao L, Lin H, Liang Y, You M, Ding L, Feng F, Yang B, Liu Y. Discovery of Antibacterial Compounds against Xanthomonas citri subsp. citri from a Marine Fungus Aspergillus terreus SCSIO 41202 and the Mode of Action. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024. [PMID: 38771666 DOI: 10.1021/acs.jafc.4c02769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a severe citrus disease. Currently, copper-containing pesticides are widely used to manage this disease, posing high risks to the environment and human health. This study reports the discovery of naturally occurring anti-Xcc compounds from a deep-sea fungus, Aspergillus terreus SCSIO 41202, and the possible mode of action. The ethyl acetate extract of A. terreus was subjected to bioassay-guided isolation, resulting in the discovery of eight anti-Xcc compounds (1-8) with minimum inhibitory concentrations (MICs) ranging from 0.078 to 0.625 mg/mL. The chemical structures of these eight metabolites were determined by integrative analysis of various spectroscopic data. Among these compounds, Asperporonin A (1) and Asperporonin B (2) were identified as novel compounds with a very unusual structural skeleton. The electronic circular dichroism was used to determine the absolute configurations of 1 and 2 through quantum chemical calculation. A bioconversion pathway involving pinacol rearrangement was proposed to produce the unusual compounds (1-2). Compound 6 exhibited an excellent anti-Xcc effect with a MIC value of 0.078 mg/mL, which was significantly more potent than the positive control CuSO4 (MIC = 0.3125 mg/mL). Compound 6 inhibited cell growth by disrupting biofilm formation, destroying the cell membrane, and inducing the accumulation of reactive oxygen species. In vivo tests indicated that compound 6 is highly effective in controlling citrus canker disease. These results indicate that compounds 1-8, especially 6, have the potential as lead compounds for the development of new, environmentally friendly, and efficient anti-Xcc pesticides.
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Affiliation(s)
- Jun Zhang
- National Engineering Research Center of Navel Orange, Gannan Normal University, Ganzhou 341000, China
| | - Liangliang Gao
- National Engineering Research Center of Navel Orange, Gannan Normal University, Ganzhou 341000, China
| | - Huiting Lin
- National Engineering Research Center of Navel Orange, Gannan Normal University, Ganzhou 341000, China
| | - Yan Liang
- National Engineering Research Center of Navel Orange, Gannan Normal University, Ganzhou 341000, China
| | - Mingnan You
- National Engineering Research Center of Navel Orange, Gannan Normal University, Ganzhou 341000, China
| | - Lijian Ding
- Department of Marine Pharmacy, Ningbo University, Ningbo 315211, China
| | - Fangjian Feng
- Department of Marine Pharmacy, Ningbo University, Ningbo 315211, China
| | - Bin Yang
- Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510000, P. R. China
| | - Yonghong Liu
- Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510000, P. R. China
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Nayana RUK, Nakkeeran S, Saranya N, Saravanan R, Mahendra K, Ashraf S, Perveen K, Alshaikh NA, Sayyed RZ, Show PL. Triamcinolone Acetonide Produced by Bacillus velezensis YEBBR6 Exerts Antagonistic Activity Against Fusarium oxysporum f. sp. Cubense: A Computational Analysis. Mol Biotechnol 2023:10.1007/s12033-023-00797-w. [PMID: 37556108 DOI: 10.1007/s12033-023-00797-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 06/13/2023] [Indexed: 08/10/2023]
Abstract
Fusarium oxysporum f. sp. cubense is one of the most severe and threatening pathogens of bananas, causing "Panama wilt" worldwide. Confrontation assay of Foc antagonistic bacterial endophyte, Bacillus velezensis YEBBR6, with the Foc and GC-MS profiling of excised agar from the zone of inhibition, led to the unveiling of secondary metabolites produced by the endophyte. To refine the probable antifungal compounds among the numerous biomolecules formed during their di-trophic interaction with the pathogen, fungal protein targets were modeled, and docking studies (AutoDock Vina module of the PyRx 0.8 server) were done with all the compounds. Triamcinolone acetonide exhibited the most excellent affinity for the protein targets among the compounds studied. It had a maximum binding affinity of 11.2 kcal/mol for XRN2 (5' → 3'). Further, the protein-ligand complex formation kinetics was done through Molecular Dynamic Simulation studies. Graphs for the RMSD, RMSF, Rg, potential energy, and SASA were generated, and the values during the simulation period suggested the stability of the biomolecule as a complex with the protein. This indicated Triamcinolone acetonide's potential ability to act as a functional disrupter of the target protein and likely an antifungal molecule. Further, the biomolecule was tested for its activity against Foc by screening in the wet lab through the poisoned plate technique, and it was found to be fully inhibitory to the growth of the pathogen at 1000 ppm.
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Affiliation(s)
- R U Krishna Nayana
- Department of Plant Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - S Nakkeeran
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India.
| | - N Saranya
- Department of Plant Molecular Biology and Bioinformatics, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - R Saravanan
- Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - K Mahendra
- Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Suhail Ashraf
- Department of Plant Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Kahkashan Perveen
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box-22452, Riyadh, 11495, Saudi Arabia
| | - Najla A Alshaikh
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box-22452, Riyadh, 11495, Saudi Arabia
| | - R Z Sayyed
- Department of Microbiology, PSGVP Mandal's, S. I. Patil Arts, G.B. Patel Science and STKV Sangh Commerce College, Shahada, 425409, India.
- Faculty of Health and Life Sciences, INTI International University, Persiaran Perdana BBN, Putra Nilai, 71800, Nilai, Negeri Sembilan, Malaysia.
| | - Pau Loke Show
- Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou, 325035, China.
- Department of Chemical Engineering, Khalifa University, Shakhbout Bin Sultan St - Zone 1, Abu Dhabi, United Arab Emirates.
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia.
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Gaurav I, Thakur A, Kumar G, Long Q, Zhang K, Sidu RK, Thakur S, Sarkar RK, Kumar A, Iyaswamy A, Yang Z. Delivery of Apoplastic Extracellular Vesicles Encapsulating Green-Synthesized Silver Nanoparticles to Treat Citrus Canker. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1306. [PMID: 37110891 PMCID: PMC10146377 DOI: 10.3390/nano13081306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 06/19/2023]
Abstract
The citrus canker pathogen Xanthomonas axonopodis has caused severe damage to citrus crops worldwide, resulting in significant economic losses for the citrus industry. To address this, a green synthesis method was used to develop silver nanoparticles with the leaf extract of Phyllanthus niruri (GS-AgNP-LEPN). This method replaces the need for toxic reagents, as the LEPN acts as a reducing and capping agent. To further enhance their effectiveness, the GS-AgNP-LEPN were encapsulated in extracellular vesicles (EVs), nanovesicles with a diameter of approximately 30-1000 nm naturally released from different sources, including plant and mammalian cells, and found in the apoplastic fluid (APF) of leaves. When compared to a regular antibiotic (ampicillin), the delivery of APF-EV-GS-AgNP-LEPN and GS-AgNP-LEPN to X. axonopodis pv. was shown to have more significant antimicrobial activity. Our analysis showed the presence of phyllanthin and nirurinetin in the LEPN and found evidence that both could be responsible for antimicrobial activity against X. axonopodis pv. Ferredoxin-NADP+ reductase (FAD-FNR) and the effector protein XopAI play a crucial role in the survival and virulence of X. axonopodis pv. Our molecular docking studies showed that nirurinetin could bind to FAD-FNR and XopAI with high binding energies (-10.32 kcal/mol and -6.13 kcal/mol, respectively) as compared to phyllanthin (-6.42 kcal/mol and -2.93 kcal/mol, respectively), which was also supported by the western blot experiment. We conclude that (a) the hybrid of APF-EV and GS-NP could be an effective treatment for citrus canker, and (b) it works via the nirurinetin-dependent inhibition of FAD-FNR and XopAI in X. axonopodis pv.
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Affiliation(s)
- Isha Gaurav
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR 999077, China
| | - Abhimanyu Thakur
- Ben May Department for Cancer Research, Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Gaurav Kumar
- Clinical Research Division, Department of Biosciences, School of Basic and Applied Sciences, Galgotias University, Greater Noida 203201, Uttar Pradesh, India
| | - Qin Long
- Citrus Research Institute, Southwest University, Chinese Academy of Agricultural Sciences, National Citrus Engineering Research Center, Chongqing 400712, China
| | - Kui Zhang
- Ben May Department for Cancer Research, Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Rakesh Kumar Sidu
- School of Biomedical Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Sudha Thakur
- National Institute for Locomotor Disabilities (Divyangjan), Kolkata 700090, India
| | - Rajesh Kumar Sarkar
- Department of Medicine, Division of Biological Sciences, University of Chicago, Chicago, IL 60637, USA
| | - Anoop Kumar
- Department of Pharmacology, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi 110017, India
| | - Ashok Iyaswamy
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR 999077, China
- Mr. & Mrs. Ko Chi-Ming Centre for Parkinson’s Disease Research, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR 999077, China
- Department of Biochemistry, Karpagam Academy of Higher Education, Coimbatore 641021, India
| | - Zhijun Yang
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR 999077, China
- Changshu Research Institute, Hong Kong Baptist University, Changshu Economic and Technological Development (CETD) Zone, Changshu 215500, China
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Hernández-Huerta J, Tamez-Guerra P, Gomez-Flores R, Delgado-Gardea MCE, Robles-Hernández L, Gonzalez-Franco AC, Infante-Ramirez R. Pepper growth promotion and biocontrol against Xanthomonas euvesicatoria by Bacillus cereus and Bacillus thuringiensis formulations. PeerJ 2023; 11:e14633. [PMID: 36710864 PMCID: PMC9881471 DOI: 10.7717/peerj.14633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/04/2022] [Indexed: 01/25/2023] Open
Abstract
Background Bacillus genus has been used in horticultural crops as a biocontrol agent against insect pests, microbial phytopathogens, and plant growth-promoting bacteria (PGPB), representing an alternative to agrochemicals. In particular, B. cereus (Bc) and B. thuringiensis (Bt) have been studied for their fungicidal and insecticidal activities. However, their use as biofertilizer formulations and biocontrol agents against phytopathogenic bacteria is limited. Objective To evaluate Bc and Bt formulations as PGPB and biocontrol agents against the bacterial spot agent Xanthomonas euvesicatoria (Xe) in greenhouse-grown chili peppers. Methods Bc and Bt isolates obtained from soil samples were identified and characterized using conventional biochemical and multiplex PCR identification methods. Bioassays to determine Bc and Bt isolates potential as PGPB were evaluated on chili pepper seedlings in seedbeds. In addition, formulations based on Bc (F-BC26 and F-BC08) and Bt (F-BT24) strains were assessed as biofertilizers on pepper, under controlled conditions. Furthermore, in vitro antagonism assays were performed by confronting Bc and Bt isolate formulations against Xe isolates in direct (foliage) and indirect (resistance induction) phytopathogen biocontrol assays on pepper plants, which were grown under controlled conditions for 15 d after formulations treatment. Results Isolates were identified as Bc and Bt. Formulations significantly improved pepper growth in seedbeds and pots, whereas in vitro bioassays demonstrated the bactericidal effect of Bc and Bt strains against Xe isolates. Furthermore, assays showed significant plant protection by F-BC26, F-BC08, and F-BT24 formulated strains against Xe. Conclusion Results indicated that F-BT24 and F-BC26 isolates formulations promoted pepper growth and protected it against Xanthomonas euvesicatoria.
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Affiliation(s)
- Jared Hernández-Huerta
- Facultad de Ciencias Agrotecnológicas, Universidad Autónoma de Chihuahua, Chihuahua, México
| | - Patricia Tamez-Guerra
- Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, México
| | - Ricardo Gomez-Flores
- Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, Nuevo León, México
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Shahbaz E, Ali M, Shafiq M, Atiq M, Hussain M, Balal RM, Sarkhosh A, Alferez F, Sadiq S, Shahid MA. Citrus Canker Pathogen, Its Mechanism of Infection, Eradication, and Impacts. PLANTS (BASEL, SWITZERLAND) 2022; 12:plants12010123. [PMID: 36616252 PMCID: PMC9824702 DOI: 10.3390/plants12010123] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/14/2022] [Accepted: 12/13/2022] [Indexed: 05/16/2023]
Abstract
Citrus canker is a ravaging bacterial disease threatening citrus crops. Its major types are Asiatic Canker, Cancrosis B, and Cancrosis C, caused by Xanthomonas citri pv. citri (Xcc), Xanthomonas citri pv. aurantifolii pathotype-B (XauB), and pathotype-C (XauC), respectively. The bacterium enters its host through stomata and wounds, from which it invades the intercellular spaces in the apoplast. It produces erumpent corky necrotic lesions often surrounded by a chlorotic halo on the leaves, young stems, and fruits, which causes dark spots, defoliation, reduced photosynthetic rate, rupture of leaf epidermis, dieback, and premature fruit drop in severe cases. Its main pathogenicity determinant gene is pthA, whose variants are present in all citrus canker-causing pathogens. Countries where citrus canker is not endemic adopt different methods to prevent the introduction of the pathogen into the region, eradicate the pathogen, and minimize its dissemination, whereas endemic regions require an integrated management program to control the disease. The main aim of the present manuscript is to shed light on the pathogen profile, its mechanism of infection, and fruitful strategies for disease management. Although an adequate method to completely eradicate citrus canker has not been introduced so far, many new methods are under research to abate the disease.
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Affiliation(s)
- Esha Shahbaz
- Department of Food Sciences, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Mobeen Ali
- Department of Horticulture, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Muhammad Shafiq
- Department of Horticulture, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Muhammad Atiq
- Department of Plant Pathology, University of Agriculture, Faisalabad 38000, Pakistan
| | - Mujahid Hussain
- Horticultural Science Department, North Florida Research and Education Center, University of Florida/IFAS, Quincy, FL 32351, USA
| | - Rashad Mukhtar Balal
- Department of Horticulture, College of Agriculture, University of Sargodha, Sargodha 40100, Pakistan
| | - Ali Sarkhosh
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
| | - Fernando Alferez
- Horticultural Science Department, Southwest Florida Research and Education Center, University of Florida/IFAS, Immokalee, FL 34142, USA
| | - Saleha Sadiq
- Department of Horticulture, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Muhammad Adnan Shahid
- Horticultural Science Department, North Florida Research and Education Center, University of Florida/IFAS, Quincy, FL 32351, USA
- Correspondence:
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Zhang Q, Li M, Yang G, Liu X, Yu Z, Peng S. Protocatechuic acid, ferulic acid and relevant defense enzymes correlate closely with walnut resistance to Xanthomonas arboricola pv. juglandis. BMC PLANT BIOLOGY 2022; 22:598. [PMID: 36539704 PMCID: PMC9764544 DOI: 10.1186/s12870-022-03997-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND Juglans regia L. is an important nut tree that has a wide range of distribution in temperate regions of the world. In some walnut orchards, walnut blight can become a problematic disease that affects the growth of walnut trees. To explore the correlation between biochemical response and walnut resistance, we inoculated four walnut cultivars with Xanthomonas arboricola pv. juglandis (Xaj). The walnut cultivars were, namely, 'Xiangling', 'Xiluo 2', 'Yuanfeng' and 'Xifu 2'. Total phenol content (TPC) and total flavonoid content (TFC) were measured, whereby nine major phenolic compounds and several relevant enzymes were identified. RESULTS The results showed that the most resistant and susceptible walnut varieties were 'Xiluo 2' and 'Xifu 2' respectively. The reaction of walnut to Xaj was characterized by the early accumulation of phenolic compounds in the infected site. After inoculation with Xaj, we found that the resistant variety 'Xiluo 2' show the significant differences with other varieties at different time points through the determination of related antioxidant enzymes such as catalase (CAT) and peroxidase (POD). Meanwhile, the phenylalanine ammonia lyase (PAL) of 'Xiluo 2' increased significantly at 8 day post infection (dpi) and made differences from the control samples, while other varieties changed little. And the polyphenol oxidase (PPO) was significantly higher than in the control at 16 dpi, maintaining the highest and the lowest activity in 'Xiluo 2' and 'Xifu 2' respectively. It was also found that the content of protocatechuic acid in all cultivars increased significantly at 4 dpi, and 'Xiluo 2' was significantly higher than that of the control. In the early stage of the disease, ferulic acid content increased significantly in 'Xiluo 2'. CONCLUSION Our findings confirmed that the metabolism of phenolic compounds and related defense enzymes are of great significance in the response of walnut to Xaj.
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Affiliation(s)
- Qian Zhang
- Laboratory of Walnut Research Center, College of Forestry, Northwest A & F University, Shaanxi, 712100, Yangling, China
| | - Meixuan Li
- Laboratory of Walnut Research Center, College of Forestry, Northwest A & F University, Shaanxi, 712100, Yangling, China
| | - Guiyan Yang
- Laboratory of Walnut Research Center, College of Forestry, Northwest A & F University, Shaanxi, 712100, Yangling, China
| | - Xiaoqiang Liu
- Department of Foreign Languages, Northwest A & F University, Shaanxi, 712100, Yangling, China
| | - Zhongdong Yu
- Laboratory of Walnut Research Center, College of Forestry, Northwest A & F University, Shaanxi, 712100, Yangling, China
| | - Shaobing Peng
- Laboratory of Walnut Research Center, College of Forestry, Northwest A & F University, Shaanxi, 712100, Yangling, China.
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Bellanger N, Dereeper A, Koebnik R. Clustered Regularly Interspaced Short Palindromic Repeats in Xanthomonas citri—Witnesses to a Global Expansion of a Bacterial Pathogen over Time. Microorganisms 2022; 10:microorganisms10091715. [PMID: 36144317 PMCID: PMC9504256 DOI: 10.3390/microorganisms10091715] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/09/2022] [Accepted: 08/23/2022] [Indexed: 11/18/2022] Open
Abstract
Xanthomonas citri pv. citri, a Gram-negative bacterium, is the causal agent of citrus canker, a significant threat to citrus production. Understanding of global expansion of the pathogen and monitoring introduction into new regions are of interest for integrated disease management at the local and global level. Genetic diversity can be assessed using genomic approaches or information from partial gene sequences, satellite markers or clustered regularly interspaced short palindromic repeats (CRISPR). Here, we compared CRISPR loci from 355 strains of X. citri pv. citri, including a sample from ancient DNA, and generated the genealogy of the spoligotypes, i.e., the absence/presence patterns of CRISPR spacers. We identified 26 novel spoligotypes and constructed their likely evolutionary trajectory based on the whole-genome information. Moreover, we analyzed ~30 additional pathovars of X. citri and found that the oldest part of the CRISPR array was present in the ancestor of several pathovars of X. citri. This work presents a framework for further analyses of CRISPR loci and allows drawing conclusions about the global spread of the citrus canker pathogen, as exemplified by two introductions in West Africa.
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Sharma M, Mallubhotla S. Diversity, Antimicrobial Activity, and Antibiotic Susceptibility Pattern of Endophytic Bacteria Sourced From Cordia dichotoma L. Front Microbiol 2022; 13:879386. [PMID: 35633730 PMCID: PMC9136406 DOI: 10.3389/fmicb.2022.879386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/11/2022] [Indexed: 12/03/2022] Open
Abstract
Endophytic bacteria isolated from medicinal plants are crucial for the production of antimicrobial agents since they are capable of possessing bioactive compounds with diverse structures and activities. Cordia dichotoma, a plant of medicinal importance native to the Jammu region of India, was selected for the isolation and characterization of culturable endophytic bacteria and evaluation of their antimicrobial activities. Standardized surface sterilization methods were employed to isolate thirty-three phenotypically distinguishable endophytic bacteria from the root, stem, and leaf parts of the plant. Shannon Wiener diversity index clearly divulged diverse endophytes in roots (0.85), stem (0.61), and leaf (0.54) tissues. Physio-biochemical features of the isolates differentiated the distinct variations in their carbohydrate utilization profile and NaCl tolerance. The endophytes produced an array of enzymes, namely, catalase, oxidase, amylase, cellulase, nitrate reductase, and lipase. The bacterial isolates belong to the genera Bacillus, Pseudomonas, Paenibacillus, Acidomonas, Streptococcus, Ralstonia, Micrococcus, Staphylococcus, and Alcalignes predominantly. However, the antibiotic susceptibility pattern indicated that the isolates were mostly sensitive to erythromycin and streptomycin, while they were resistant to rifampicin, amoxicillin, and bacitracin. Interestingly, majority of the bacterial endophytes of C. dichotoma showed antimicrobial activity against Bacillus subtilis followed by Klebsiella pneumoniae. The 16S rRNA sequence of Bacillus thuringiensis has been deposited in the NCBI GenBank database under accession number OM320575. The major compounds of the crude extract derived from endophytic B. thuringiensis OM320575, according to the metabolic profile examination by GC-MS, are dibutyl phthalate, eicosane, tetrapentacontane, heneicosane, and hexadecane, which possessed antibacterial activities. In conclusion, results indicated the potential of C. dichotoma to host a plethora of bacterial endophytes that produce therapeutic bioactive metabolites.
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Predicting the impact of environmental factors on citrus canker through multiple regression. PLoS One 2022; 17:e0260746. [PMID: 35381013 PMCID: PMC8982892 DOI: 10.1371/journal.pone.0260746] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/17/2021] [Indexed: 11/19/2022] Open
Abstract
Climatic conditions play a significant role in the development of citrus canker caused by Xanthomonas citri pv. citri (Xcc). Citrus canker is regarded as one of the major threats being faced by citrus industry in citrus growing countries of the world. Climatic factors exert significant impacts on growth stage, host susceptibility, succulence, vigor, survival, multiplication rate, pathogen dispersion, spore penetration rate, and spore germination. Predicting the impacts of climatic factors on these traits could aid in the development of effective management strategies against the disease. This study predicted the impacts of environmental variables, i.e., temperature, relative humidity, rainfall, and wind speed the development of citrus canker through multiple regression. These environmental variables were correlated with the development of canker on thirty (30) citrus varieties during 2017 to 2020. Significant positive correlations were noted among environment variables and disease development modeled through multiple regression model (Y = +24.02 + 0.5585 X1 + 0.2997 X2 + 0.3534 X3 + 3.590 X4 + 1.639 X5). Goodness of fit of the model was signified by coefficient determination value (97.5%). Results revealed the optimum values of environmental variables, i.e., maximum temperature (37°C), minimum temperature (27°C), relative humidity (55%), rainfall (4.7-7.1 mm) and wind speed (8 Km/h), which were conducive for the development of citrus canker. Current study would help researchers in designing better management strategies against citrus canker disease under changing climatic conditions in the future.
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Duan S, Long Y, Cheng S, Li J, Ouyang Z, Wang N. Rapid Evaluation of the Resistance of Citrus Germplasms Against Xanthomonas citri subsp. citri. PHYTOPATHOLOGY 2022; 112:765-774. [PMID: 34495678 DOI: 10.1094/phyto-04-21-0175-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus bacterial canker (CBC), one of the most devastating citrus diseases. Most commercial citrus varieties are susceptible to CBC. However, some citrus varieties and wild citrus germplasms are CBC resistant and are promising in genetic increases in citrus resistance against CBC. We aimed to evaluate citrus germplasms for resistance against CBC. First, we developed a rapid evaluation method based on enhanced yellow fluorescent protein (eYFP)-labeled Xcc. The results demonstrated that eYFP does not affect the growth and virulence of Xcc. Xcc-eYFP allows measurement of bacterial titers but is more efficient and rapid than the plate colony counting method. Next, we evaluated citrus germplasms collected in China. Based on symptoms and bacterial titers, we identified that two citrus germplasms ('Ichang' papeda and 'Huapi' kumquat) are resistant, whereas eight citrus germplasms ('Chongyi' wild mandarin, 'Mangshan' wild mandarin, 'Ledong' kumquat, 'Dali' citron, 'Yiliang' citron, 'Longyan' kumquat, 'Bawang' kumquat, and 'Daoxian' wild mandarin) are tolerant. In summary, we have developed a rapid evaluation method to test the resistance of citrus plants against CBC. This method was successfully used to identify two highly canker-resistant citrus germplasms and eight citrus germplasms with canker tolerance. These results could be leveraged in traditional breeding contexts or be used to identify canker resistance genes to increase the disease resistance of commercial citrus varieties via biotechnological approaches.
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Affiliation(s)
- Shuo Duan
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Yunfei Long
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Shuyuan Cheng
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850, U.S.A
| | - Zhigang Ouyang
- Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi 341000, China
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850, U.S.A
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11
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Wang X, Liang L, Shao H, Ye X, Yang X, Chen X, Shi Y, Zhang L, Xu L, Wang J. Isolation of the Novel Strain Bacillus amyloliquefaciens F9 and Identification of Lipopeptide Extract Components Responsible for Activity against Xanthomonas citri subsp. citri. PLANTS (BASEL, SWITZERLAND) 2022; 11:457. [PMID: 35161438 PMCID: PMC8840523 DOI: 10.3390/plants11030457] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/24/2022] [Accepted: 02/05/2022] [Indexed: 06/14/2023]
Abstract
Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a quarantine disease that seriously affects citrus production worldwide. The use of microorganisms and their products for biological control has been proven to be effective in controlling Xanthomonas disease. In this study, a novel Xcc antagonistic strain was isolated and identified as Bacillus amyloliquefaciens F9 by morphological and molecular analysis. The lipopeptide extract of B. amyloliquefaciens F9 (F9LE) effectively inhibited the growth of Xcc in an agar diffusion assay and restrained the occurrence of canker lesions in a pathogenicity test under greenhouse conditions. Consistent with these findings, F9LE treatment significantly inhibited the production of extracellular enzymes in Xcc cells and induced cell wall damage, with leakage of bacterial contents revealed by scanning electron microscopy and transmission electron microscopy analyses. In addition, F9LE also showed strong antagonistic activity against a wide spectrum of plant pathogenic bacteria and fungi. Furthermore, using electrospray ionization mass spectrometry analysis, the main antimicrobial compounds of strain F9 were identified as three kinds of lipopeptides, including homologues of surfactin, fengycin, and iturin. Taken together, our results show that B. amyloliquefaciens F9 and its lipopeptide components have the potential to be used as biocontrol agents against Xcc, and other plant pathogenic bacteria and fungi.
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Affiliation(s)
- Xin Wang
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
| | - Liqiong Liang
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
| | - Hang Shao
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
| | - Xiaoxin Ye
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
| | - Xiaobei Yang
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
| | - Xiaoyun Chen
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
| | - Yu Shi
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
| | - Lianhui Zhang
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
| | - Linghui Xu
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
| | - Junxia Wang
- Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (X.W.); (L.L.); (H.S.); (X.Y.); (X.Y.); (X.C.); (Y.S.); (L.Z.)
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China
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12
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Rabbee MF, Islam N, Baek KH. Biocontrol of citrus bacterial canker caused by Xanthomonas citri subsp. citri by Bacillus velezensis. Saudi J Biol Sci 2021; 29:2363-2371. [PMID: 35531204 PMCID: PMC9072923 DOI: 10.1016/j.sjbs.2021.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 12/03/2021] [Accepted: 12/04/2021] [Indexed: 11/18/2022] Open
Abstract
Microorganisms with biocontrol capabilities against plant pathogens are considered as one of the most promising approaches for healthy crop management. In this study, ethyl acetate extracts of 25 Bacillus strains were investigated for their antagonistic effect on Xanthomonas citri subsp. citri (Xcc), which causes the citrus bacterial canker (CBC) disease. Among them, 21 strains exerted antibacterial activity against wild-type Xcc strains. Based on the strength of the antibacterial activity, nine Bacillus strains were selected for 16S rRNA analysis. 16S rRNA sequence homology revealed that several strains were closely related to B. velezensis, where strains with no antibacterial activity grouped as the soil-associated community of B. amyloliquefaciens. B. velezensis Bv-21 exhibited the highest antibacterial activity against wild type and streptomycin resistant Xcc with inhibition zones of 22.91 ± 0.45 and 20.28 ± 0.53, respectively. Furthermore, B. velezensis Bv-21 strain was tested for biocontrol activity against a streptomycin-resistant XccM4 in detached susceptible citrus leaves. The strain reduced the incidence of CBC by 26.30% and pathogen density of XccM4 by 81.68% over control. The results of the study strongly suggest that B. velezensis can be used as an effective and eco-friendly biocontrol agent either by itself or as an active compound, against both, the wild-type and streptomycin-resistant Xcc.
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Affiliation(s)
- Muhammad Fazle Rabbee
- Department of Biotechnology, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Nurul Islam
- Soil Resource Development Institute, Regional Office, Rajshahi 6000, Bangladesh
| | - Kwang-Hyun Baek
- Department of Biotechnology, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea
- Corresponding author.
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13
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Caccalano MN, Dilarri G, Zamuner CFC, Domingues DS, Ferreira H. Hexanoic acid: a new potential substitute for copper-based agrochemicals against citrus canker. J Appl Microbiol 2021; 131:2488-2499. [PMID: 34008224 DOI: 10.1111/jam.15125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/29/2021] [Accepted: 04/11/2021] [Indexed: 01/16/2023]
Abstract
AIMS The aim of the study is to evaluate hexanoic acid (HA) as an alternative to manage citrus canker. METHODS AND RESULTS The minimal growth inhibitory concentration of HA against Xanthomonas citri subsp. citri was determined at 2·15 mmol l-1 using a respiratory activity assay. Growth curves at different pH values showed that growth inhibition was not due to media acidification induced by HA. The germination rate and root elongation of Lactuca sativa seeds exposed to different concentrations of HA (varying from 0·86 to 5·16 mmol l-1 ) were assessed to screen for phytotoxicity. The acid exhibited low phytotoxicity for L. sativa at 1·29 and 2·58 mmol l-1 . To evaluate the ability of HA to protect citrus against X. citri infection, leaves of Citrus sinensis were sprayed with the acid and subsequently challenged with X. citri. HA at 3·44 mmol l-1 was able to protect citrus against infection, showing a reduction of three orders of magnitude in the number of citrus canker lesions per cm2 when compared to the untreated negative control. CONCLUSION HA is a potential alternative to copper for citrus canker management. SIGNIFICANCE AND IMPACT OF THE STUDY HA inhibits X. citri growth, exhibits low phytotoxicity and is an alternative to copper for the protection of citrus plants against bacterial infection.
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Affiliation(s)
- M N Caccalano
- Department of General and Applied Biology, Sao Paulo State University (UNESP), Rio Claro, Brazil
| | - G Dilarri
- Department of General and Applied Biology, Sao Paulo State University (UNESP), Rio Claro, Brazil
| | - C F C Zamuner
- Department of General and Applied Biology, Sao Paulo State University (UNESP), Rio Claro, Brazil
| | - D S Domingues
- Department of Biodiversity, Sao Paulo State University (UNESP), Rio Claro, Brazil
| | - H Ferreira
- Department of General and Applied Biology, Sao Paulo State University (UNESP), Rio Claro, Brazil
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14
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Xu T, Jiang W, Qin D, Liu T, Zhang J, Chen W, Gao L. Characterization of the microbial communities in wheat tissues and rhizosphere soil caused by dwarf bunt of wheat. Sci Rep 2021; 11:5773. [PMID: 33707584 PMCID: PMC7952392 DOI: 10.1038/s41598-021-85281-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/26/2021] [Indexed: 11/11/2022] Open
Abstract
Dwarf bunt of wheat, which is caused by Tilletia controversa J.G. Kühn, is a soil-borne disease which may lead up to an 80% loss of yield together with degradation of the quality of the wheat flour by production of a fishy smell. In this study, high-throughput sequencing technology was employed to characterize the microbial composition of wheat tissues (roots, spikes, first stem under the ear, and stem base) and rhizosphere soil of wheat varieties that are resistant and susceptible to T. controversa. We observed that the soil fungal community abundance and diversity were higher in resistant varieties than in susceptible varieties in both inoculated and uninoculated wheat, and the abundances of Sordariomycetes and Mortierellomycetes increased in the resistant varieties infected with T. controversa, while the abundances of Dothideomycetes and Bacteroidia increased in the susceptible varieties. Regarding the bacteria present in wheat tissues, the abundances of Chloroflexi, Bacteroidetes, Gemmatimonadetes, Verrucomicrobia and Acidobacteria in the ear and the first stem under the ear were higher than those in other tissues. Our results indicated that the abundances of Sordariomycetes, Mortierellomycetes, Leotiomycetes, Chryseobacterium and Massilia were higher in T. controversa-infected resistant varieties than in their controls, that Dothideomycetes, Bacteroidia, Nocardioides and Pseudomonas showed higher abundances in T. controversa-infected susceptible varieties, and that Curtobacterium, Exiguobacterium, Planococcus, and Pantoea may have higher abundances in both T. controversa-infected susceptible and resistant varieties than in their own controls.
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Affiliation(s)
- Tongshuo Xu
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wenli Jiang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.,School of Agriculture, Yangtze University, Jingzhou, China
| | - Dandan Qin
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Taiguo Liu
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jianmin Zhang
- School of Agriculture, Yangtze University, Jingzhou, China
| | - Wanquan Chen
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Li Gao
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
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15
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Villamizar S, Ferro JA, Caicedo JC, Alves LMC. Bactericidal Effect of Entomopathogenic Bacterium Pseudomonas entomophila Against Xanthomonas citri Reduces Citrus Canker Disease Severity. Front Microbiol 2020; 11:1431. [PMID: 32670251 PMCID: PMC7327231 DOI: 10.3389/fmicb.2020.01431] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 06/02/2020] [Indexed: 12/17/2022] Open
Abstract
The bacterium Pseudomonas entomophila has been recognized as an exceptional species within the Pseudomonas genus, capable of naturally infecting and killing insects from at least three different orders. P. entomophila ingestion leads to irreversible gut damage resulting from a global blockage of translation, which impairs both immune and tissue repair systems in the insect intestine. In this study we isolated a P. entomophila bacterial strain from soil samples which displayed a strong activity against Xanthomonas citri subsp, citri (Xcc), the etiological agent of citrus canker disease. The antagonism potential of isolated bacteria against Xcc and its ability to reduce citrus canker severity was assessed both ex planta and in planta. Our findings show that pathogenicity assays in Citrus x limonia by pressure infiltration and spray with a mixture of P. entomophila and Xcc leaded to a significant reduction in the number of canker lesions in high susceptible citrus leaves, at 21 days post-infection. To the best of our knowledge this is the first report of antibacterial activity of P. entomophila against a phytopathogenic bacterium. Collective action of P. entomophila factors such as diketopiperazine production and the type 6 secretion system (T6SS) may be involved in this type of biological control of citrus canker. The results suggest that the P. entomophila strain could be a promising biocontrol agent acting directly against Xcc.
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Affiliation(s)
- Sonia Villamizar
- Post Graduate Program in Agricultural and Livestock Microbiology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, Brazil
| | - Jesus Aparecido Ferro
- Post Graduate Program in Agricultural and Livestock Microbiology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, Brazil
| | - Juan Carlos Caicedo
- Post Graduate Program in Agricultural and Livestock Microbiology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, Brazil.,Faculty of Exact, Natural and Agricultural Sciences, Research Group CIBAS, Universidad de Santander (UDES), Bucaramanga, Colombia
| | - L M C Alves
- Post Graduate Program in Agricultural and Livestock Microbiology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, Brazil
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