Bchex a virulence gen of Botrytis cinerea: characterization and functional analyses.
ABSTRACT: We previously identified Bchex as a highly expressed gene during filamentous growth in Botrytis cinerea. The gene encodes the principal protein of the Woronin body and has been shown to seal septal pores in response to cellular damage. In the present study, Southern blot analysis of genomic DNA indicated that the gene exists as a single copy in the B. cinerea genome. The gene was differentially expressed during various developmental stages: expression was high in germinating conidia and the mycelial stage and lower in resting conidia and the appressorial stage. For functional analyses, homologous recombination was used to obtain a ΔBchex knockout mutant. Growth of the mutant was strongly reduced growth in complete medium and in defined media with sucrose, fructose or pectin as the carbon source. After detached tomato leaves were inoculated with the Bchex mutant, lesion development was markedly reduced compared to the control, suggesting that Bchex participates in normal growth, germination and virulence of this fungus.