Transcription Factor Amr1 Induces Melanin Biosynthesis and Suppresses Virulence in Alternaria brassicicola

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dc.contributorVirginia Techen
dc.contributor.authorCho, Yangraeen
dc.contributor.authorSrivastava, Akhilen
dc.contributor.authorOhm, Robin A.en
dc.contributor.authorLawrence, Christopher B.en
dc.contributor.authorWang, Koon-Huien
dc.contributor.authorGrigoriev, Igor V.en
dc.contributor.authorMarahatta, Sharadchandra P.en
dc.date.accessed2014-04-03en
dc.date.accessioned2014-04-09T15:07:21Zen
dc.date.available2014-04-09T15:07:21Zen
dc.date.issued2012-10-25en
dc.description.abstractAlternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. Several A. brassicicola genes have been characterized as affecting pathogenesis of Brassica species. To study regulatory mechanisms of pathogenesis, we mined 421 characterized as affecting pathogenesis of Brassica species. To study regulatory mechanisms of pathogenesis, we mined 421 genes in silico encoding putative transcription factors in a machine-annotated, draft genome sequence of A. brassicicola. In this study, targeted gene disruption mutants for 117 of the transcription factor genes were produced and screened. Three of these genes were associated with pathogenesis. Disruption mutants of one gene (AbPacC) were nonpathogenic and another gene (AbVf8) caused lesions less than half the diameter of wild-type lesions. Unexpectedly, mutants of the third gene, Amr1, caused lesions with a two-fold larger diameter than the wild type and complementation mutants. Amr1 is a homolog of Cmr1, a transcription factor that regulates melanin biosynthesis in several fungi. We created gene deletion mutants of Damr1 and characterized their phenotypes. The Damr1 mutants used pectin as a carbon source more efficiently than the wild type, were melanin-deficient, and more sensitive to UV light and glucanase digestion. The AMR1 protein was localized in the nuclei of hyphae and in highly melanized conidia during the late stage of plant pathogenesis. RNA-seq analysis revealed that three genes in the melanin biosynthesis pathway, along with the deleted Amr1 gene, were expressed at low levels in the mutants. In contrast, many hydrolytic enzyme-coding genes were expressed at higher levels in the mutants than in the wild type during pathogenesis. The results of this study suggested that a gene important for survival in nature negatively affected virulence, probably by a less efficient use of plant cell-wall materials. We speculate that the functions of the Amr1 gene are important to the success of A. brassicicola as a competitive saprophyte and plant parasite.en
dc.description.sponsorshipThis research was supported by USDA-TSTAR 2009-34135-20197 and HATCH funds to YC, administered by the College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, HI. Analysis of RNA-seq data and downstream analyses were done by the U.S. Department of Energy Joint Genome Institute that is supported by the Office of Science of the U.S. Department of Energy under contract number DE-AC02-05CH11231. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.en
dc.identifier.citationCho Y, Srivastava A, Ohm RA, et al. Transcription Factor Amr1 Induces Melanin Biosynthesis and Suppresses Virulence in Alternaria brassicicola. PLoS Pathogens. 2012;8:e1002974.en
dc.identifier.doihttps://doi.org/10.1371/journal.ppat.1002974en
dc.identifier.issn1553-7374en
dc.identifier.urihttp://hdl.handle.net/10919/47005en
dc.identifier.urlhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC3486909/#__ffn_sectitleen
dc.language.isoen_USen
dc.publisherPLOS Pathogensen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectAlternaria -- Researchen
dc.subjectPlant diseases -- Researchen
dc.subjectBrassica -- Researchen
dc.titleTranscription Factor Amr1 Induces Melanin Biosynthesis and Suppresses Virulence in Alternaria brassicicolaen
dc.title.serialPLoS Pathogensen
dc.typeArticle - Refereeden

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