The autophagy protein BcAtg2 regulates growth, development and pathogenicity in the gray mold fungus Botrytis cinerea

Abstract Autophagy is an intracellular degradation process that facilitates material recycling to maintain cellular homeostasis in eukaryotes. Atg2 is a phospholipid transfer protein involved in cellular autophagy in Saccharomyces cerevisiae . To date, the role of Atg2 in growth, development and pathogenicity of the gray mold fungus Botrytis cinerea remains unknown. In this study, we identified and characterized an Atg2 ortholog, designated as BcAtg2, in B. cinerea . Deletion of BcATG2 resulted in a block of the autophagic process in B. cinerea . The Δ BcAtg2 mutant failed to produce sclerotia, and showed significant reduction in mycelial growth rate, formation of aerial mycelium and conidiation. In addition, the Δ BcAtg2 mutant lost the ability to form infection structures and cause symptom on host plants. All of these phenotypic changes in Δ BcAtg2 mutant were restored by targeted gene complementation. Moreover, BcAtg2 was demonstrated to physically interact with the phosphoinositide binding protein BcAtg18. Taken together, these results indicate that BcAtg2 plays an important role in vegetative growth, development and pathogenicity in B. cinerea .