AUTHOR=Fu Teng , Shin Jong-Hwan , Lee Noh-Hyun , Lee Kwang Ho , Kim Kyoung Su 

TITLE=Mitogen-Activated Protein Kinase CsPMK1 Is Essential for Pepper Fruit Anthracnose by Colletotrichum scovillei

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.770119

DOI=10.3389/fmicb.2022.770119

ISSN=1664-302X

ABSTRACT=<p>The phytopathogenic fungus <italic>Colletotrichum scovillei</italic>, belonging to the <italic>Colletotrichum acutatum</italic> species complex, causes severe anthracnose disease on several fruits, including chili pepper (<italic>Capsicum annuum</italic>). However, the molecular mechanisms underlying the development and pathogenicity of <italic>Colletotrichum scovillei</italic> are unclear. The conserved Fus3/Kss1-related MAPK regulates fungal development and pathogenicity. Here, the role of <italic>CsPMK1</italic>, orthologous to <italic>Fus3/Kss1</italic>, was characterized by phenotypic comparison of a target deletion mutant (<italic>ΔCspmk1</italic>). The mycelial growth and conidiation of <italic>ΔCspmk1</italic> were normal compared to that of the wild type. <italic>ΔCspmk1</italic> produced morphologically abnormal conidia, which were delayed in conidial germination. Germinated conidia of <italic>ΔCspmk1</italic> failed to develop appressoria on inductive surfaces of hydrophobic coverslips and host plants. <italic>ΔCspmk1</italic> was completely defective in infectious growth, which may result from failure to suppress host immunity. Furthermore, <italic>ΔCspmk1</italic> was impaired in nuclear division and lipid mobilization during appressorium formation, in response to a hydrophobic surface. CsPMK1 was found to interact with CsHOX7, a homeobox transcription factor essential for appressorium formation, <italic>via</italic> a yeast two-hybridization analysis. Taken together, these findings suggest that <italic>CsPMK1</italic> is required for fungal development, stress adaptation, and pathogenicity of <italic>C. scovillei</italic>.</p>