The mitogen-activated protein kinase kinase kinase BcOs4 is required for vegetative differentiation and pathogenicity in Botrytis cinerea

• Published in: Applied microbiology and biotechnology 2012-10, Vol.96 (2), p.481-492
• Main Authors: Yang, Qianqian, Yan, Leiyan, Gu, Qin, Ma, Zhonghua
• Format: Article
• Language: English
• Subjects: Analysis; Applied Microbial and Cell Physiology; Biomedical and Life Sciences; Biotechnology; Botrytis - enzymology; Botrytis - genetics; Botrytis - growth & development; Botrytis - pathogenicity; Botrytis cinerea; Brassica rapa - microbiology; Cellular biology; Cucumis sativus - microbiology; Deletion; Differentiation; Environmental stress; Fruits; Fungal Proteins - genetics; Fungal Proteins - metabolism; Fungi; Fungicides; Gene Expression Regulation, Fungal; Genes; Genomes; Glycerin; Glycerol; Kinases; Life Sciences; Malus; MAP Kinase Kinase Kinases - genetics; MAP Kinase Kinase Kinases - metabolism; Microbial Genetics and Genomics; Microbiology; Mitogens; Mold; Oxidative stress; Pathogenesis; Pathogens; Pesticides; Phosphorylation; Plant Diseases - microbiology; Protein kinases; Proteins; Saccharomyces cerevisiae; Signal transduction; Stresses; Studies; Virulence; Vitaceae; Yeast
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-012-4029-9

The high-osmolarity glycerol signal pathway plays an important role in the response of fungi to various environmental stresses. In this study, we characterized a mitogen-activated protein kinase kinase kinase gene BcOS4 in Botrytis cinerea , which is homologous to Saccharomyces cerevisiae SSK2/SSK22 . The BcOS4 deletion mutant was significantly impaired in vegetative growth and conidial formation. The mutant exhibited increased sensitivity to the osmotic, oxidative stresses and to the fungicides iprodione and fludioxonil. Western blot analysis showed that BcSak1, a putative downstream component of BcOs4, was not phosphorylated in the mutant. In addition, the BcOS4 mutant was unable to infect leaves of rapeseed and cucumber, and grape fruits, although it can cause disease on apple fruits. All the defects were restored by genetic complementation of the BcOS4 deletion mutant with the wild-type BcOS4 gene. The data of this study indicate that BcOS4 is involved in vegetative differentiation, virulence, adaption to hyperosmotic and oxidative stresses, and to fungicides in B. cinerea .