Molecular Characterisation of the Peroxidase Gene Family in <i>Botrytis cinerea</i> and the Role of BcPRD7 in Virulence

Peroxidase activity is essential for the virulence of a number of plant-pathogenic fungi. However, there are few reports of the systematic analysis of peroxidase genes in Botrytis cinerea. We identified all the peroxidase genes of B. cinerea by searching the fungal peroxidase database and found that the expression levels of BcPRD3, BcPRD7, BcPRD8 and BcPRD10 changed significantly during hyphal development and in response to H₂O₂ stress treatment and infection of Arabidopsis thaliana by B. cinerea. We found that the hyphae of the mutant strains became more slender, the number and size of the infection structures decreased, the number of conidia decreased and the stress response and virulence decreased significantly. These four genes positively regulated the growth, development and pathogenicity of B. cinerea and participated in osmotic and oxidative stress response and cell integrity maintenance. In addition, we also found that BcPRD7 played important roles in oxidase enzyme activity, ion penetration, the synthesis and metabolism of mycotoxins, and determined the interaction between BcPRD7 and BcHEX, the latter being the major protein of the Woronin body. It is speculated that BcPRD7 may regulate the growth, development and pathogenicity of the pathogen by participating in the development of the Woronin body. The function of peroxidase family genes in B. cinerea was systematically analysed in this study, which provides a solid foundation for the subsequent in-depth elucidation of the relevant regulatory mechanisms and is expected to provide new ideas and strategies for the prevention and control of B. cinerea diseases.