Identification of new pathogenicity related to the gene encoding hypothetical protein in the gray mold fungus (Botrytis cinerea)

Abstract

Botrytis cinerea is an important necrotrophic fungus that causes gray mold disease in various important crop plants, leading to substantial economic losses. Herein, Agrobacterium tumefaciens-mediated transformation (ATMT) technique was used to create an insertional mutant library of B. cinerea to investigate its pathogenicity-related genes. Among 1,734 transformations only 46 mutants decreased the pathogenicity on tomato leaves. C2M52 is one of the 46 mutants that its pathogenicity reduction was analyzed deeply. The T-DNA integrated into the promoter region of the hypothetical protein (BcHP) gene. The gene replacement approach via homologous recombination was used to generate knock-out mutant (Δbchp) and its functional complementary (Δbchp-C) strains. The results warranted that the Δbchp mutant strain displayed a significant difference in the virulence on tomato leaves relative to the wild type. These results were consistent with the attenuated pathogenicity caused by T-DNA integration mutant (C2M52). That subsequently revealed the crucial role of BcHP gene in the pathogenicity of B. cinerea.