Characterization of Growth Morphology and Pathology, and Draft Genome Sequencing of Botrytis fabae, the Causal Organism of Chocolate Spot of Faba Bean (Vicia faba L.)

Chocolate spot is a major fungal disease of faba bean caused by the ascomycete fungus, Botrytis fabae. B. fabae is also implicated in botrytis gray mold disease in lentils, along with B. cinerea. Here we have isolated and characterized two B. fabae isolates from chocolate spot lesions on faba bean l...

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Autores principales: Lee, Robert C., Farfan-Caceres, Lina M., Debler, Johannes W., Syme, Robert A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040437/
https://www.ncbi.nlm.nih.gov/pubmed/32132988
http://dx.doi.org/10.3389/fmicb.2020.00217
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author Lee, Robert C.
Farfan-Caceres, Lina M.
Debler, Johannes W.
Syme, Robert A.
author_facet Lee, Robert C.
Farfan-Caceres, Lina M.
Debler, Johannes W.
Syme, Robert A.
author_sort Lee, Robert C.
collection PubMed
description Chocolate spot is a major fungal disease of faba bean caused by the ascomycete fungus, Botrytis fabae. B. fabae is also implicated in botrytis gray mold disease in lentils, along with B. cinerea. Here we have isolated and characterized two B. fabae isolates from chocolate spot lesions on faba bean leaves. In plant disease assays on faba bean and lentil, B. fabae was more aggressive than B. cinerea and we observed variation in susceptibility among a small set of cultivars for both plant hosts. Using light microscopy, we observed a spreading, generalized necrosis response in faba bean toward B. fabae. In contrast, the plant response to B. cinerea was localized to epidermal cells underlying germinated spores and appressoria. In addition to the species characterization of B. fabae, we produced genome assemblies for both B. fabae isolates using Illumina sequencing. Genome sequencing coverage and assembly size for B. fabae isolates, were 27x and 45x, and 43.2 and 44.5 Mb, respectively. Following genome assembly and annotation, carbohydrate-active enzyme (CAZymes) and effector genes were predicted. There were no major differences in the numbers of each of the major classes of CAZymes. We predicted 29 effector genes for B. fabae, and using the same selection criteria for B. cinerea, we predicted 34 putative effector genes. For five of the predicted effector genes, the pairwise dN/dS ratio between orthologs from B. fabae and B. cinerea was greater than 1.0, suggesting positive selection and the potential evolution of molecular mechanisms for host specificity in B. fabae. Furthermore, a homology search of secondary metabolite clusters revealed the absence of the B. cinerea phytotoxin botrydial and several other uncharacterized secondary metabolite biosynthesis genes from B. fabae. Although there were no obvious differences in the number or proportional representation of different transposable element classes, the overall proportion of AT-rich DNA sequence in B. fabae was double that of B. cinerea.
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spelling pubmed-70404372020-03-04 Characterization of Growth Morphology and Pathology, and Draft Genome Sequencing of Botrytis fabae, the Causal Organism of Chocolate Spot of Faba Bean (Vicia faba L.) Lee, Robert C. Farfan-Caceres, Lina M. Debler, Johannes W. Syme, Robert A. Front Microbiol Microbiology Chocolate spot is a major fungal disease of faba bean caused by the ascomycete fungus, Botrytis fabae. B. fabae is also implicated in botrytis gray mold disease in lentils, along with B. cinerea. Here we have isolated and characterized two B. fabae isolates from chocolate spot lesions on faba bean leaves. In plant disease assays on faba bean and lentil, B. fabae was more aggressive than B. cinerea and we observed variation in susceptibility among a small set of cultivars for both plant hosts. Using light microscopy, we observed a spreading, generalized necrosis response in faba bean toward B. fabae. In contrast, the plant response to B. cinerea was localized to epidermal cells underlying germinated spores and appressoria. In addition to the species characterization of B. fabae, we produced genome assemblies for both B. fabae isolates using Illumina sequencing. Genome sequencing coverage and assembly size for B. fabae isolates, were 27x and 45x, and 43.2 and 44.5 Mb, respectively. Following genome assembly and annotation, carbohydrate-active enzyme (CAZymes) and effector genes were predicted. There were no major differences in the numbers of each of the major classes of CAZymes. We predicted 29 effector genes for B. fabae, and using the same selection criteria for B. cinerea, we predicted 34 putative effector genes. For five of the predicted effector genes, the pairwise dN/dS ratio between orthologs from B. fabae and B. cinerea was greater than 1.0, suggesting positive selection and the potential evolution of molecular mechanisms for host specificity in B. fabae. Furthermore, a homology search of secondary metabolite clusters revealed the absence of the B. cinerea phytotoxin botrydial and several other uncharacterized secondary metabolite biosynthesis genes from B. fabae. Although there were no obvious differences in the number or proportional representation of different transposable element classes, the overall proportion of AT-rich DNA sequence in B. fabae was double that of B. cinerea. Frontiers Media S.A. 2020-02-18 /pmc/articles/PMC7040437/ /pubmed/32132988 http://dx.doi.org/10.3389/fmicb.2020.00217 Text en Copyright © 2020 Lee, Farfan-Caceres, Debler and Syme. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
Lee, Robert C.
Farfan-Caceres, Lina M.
Debler, Johannes W.
Syme, Robert A.
Characterization of Growth Morphology and Pathology, and Draft Genome Sequencing of Botrytis fabae, the Causal Organism of Chocolate Spot of Faba Bean (Vicia faba L.)
title Characterization of Growth Morphology and Pathology, and Draft Genome Sequencing of Botrytis fabae, the Causal Organism of Chocolate Spot of Faba Bean (Vicia faba L.)
title_full Characterization of Growth Morphology and Pathology, and Draft Genome Sequencing of Botrytis fabae, the Causal Organism of Chocolate Spot of Faba Bean (Vicia faba L.)
title_fullStr Characterization of Growth Morphology and Pathology, and Draft Genome Sequencing of Botrytis fabae, the Causal Organism of Chocolate Spot of Faba Bean (Vicia faba L.)
title_full_unstemmed Characterization of Growth Morphology and Pathology, and Draft Genome Sequencing of Botrytis fabae, the Causal Organism of Chocolate Spot of Faba Bean (Vicia faba L.)
title_short Characterization of Growth Morphology and Pathology, and Draft Genome Sequencing of Botrytis fabae, the Causal Organism of Chocolate Spot of Faba Bean (Vicia faba L.)
title_sort characterization of growth morphology and pathology, and draft genome sequencing of botrytis fabae, the causal organism of chocolate spot of faba bean (vicia faba l.)
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040437/
https://www.ncbi.nlm.nih.gov/pubmed/32132988
http://dx.doi.org/10.3389/fmicb.2020.00217
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