title: Loss of bcbrn1 and bcpks13 in Botrytis cinerea Not Only Blocks Melanization But Also Increases Vegetative Growth and Virulence.
abstract: Botrytis cinerea is a necrotrophic pathogen that causes gray mold disease in a broad range of plants. Dihydroxynaphthalene (DHN) melanin is a major component of the extracellular matrix of B. cinerea, but knowledge of the exact role of melanin biosynthesis in this pathogen is unclear. In this study, we characterize two genes in B. cinerea, bcpks13 and bcbrn1, encoding polyketide synthase and tetrahydroxynaphthalene (THN) reductases, respectively, and both have predicted roles in DHN melanin biosynthesis. The ∆bcpks13 and ∆bcbrn1 mutants show white and orange pigmentation, respectively, and the mutants are also deficient in conidiation in vitro but show enhanced growth rates and virulence on hosts. Moreover, the mutants display elevated acidification of the complete medium (CM), probably due to oxalic acid secretion and secretion of cell wall-degrading enzymes, and preferably utilize plant cell-wall components as carbon sources for mycelium growth in vitro. In contrast, overexpression of bcbrn1 (OE::bcbrn1 strain) results in attenuated hydrolytic enzyme secretion, acidification ability, and virulence. Taken together, these results indicate that bcpks13 and bcbrn1 participate in diverse cellular and developmental processes, such as melanization and conidiation in B. cinerea in vitro, but they negatively regulate the virulence of this pathogen.
authors.affiliation: School of Life Science, East China Normal University, Shanghai 200241, PR China.
authors.forename: Chenghua
authors.initials: C
authors.lastname: Zhang
authors.affiliation: School of Life Science, East China Normal University, Shanghai 200241, PR China.
authors.forename: Yifan
authors.initials: Y
authors.lastname: He
authors.affiliation: School of Life Science, East China Normal University, Shanghai 200241, PR China.
authors.forename: Pinkuan
authors.initials: P
authors.lastname: Zhu
authors.affiliation: School of Life Science, East China Normal University, Shanghai 200241, PR China.
authors.forename: Lu
authors.initials: L
authors.lastname: Chen
authors.affiliation: School of Life Science, East China Normal University, Shanghai 200241, PR China.
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Life Science, East China Normal University, Shanghai 200241, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Ni
authors.affiliation: School of Life Science, East China Normal University, Shanghai 200241, PR China.
authors.forename: Ling
authors.initials: L
authors.lastname: Xu
mesh_terms: D020171:Botrytis / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D002212:Capsicum / Q000382:microbiology; D005638:Fruit / Q000382:microbiology; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D015966:Gene Expression Regulation, Fungal; D025301:Hyphae; D008543:Melanins / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics* / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D048630:Polyketide Synthases / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D014026:Nicotiana / Q000382:microbiology; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D008543:Melanins; D037521:Virulence Factors; D048630:Polyketide Synthases; C086024:tetrahydroxynaphthalene reductase; D044925:Oxidoreductases Acting on CH-CH Group Donors