Leaf Structure and Hormonal Balance Modulate Host‐Specificity and Pathogenicity of <i>Botrytis cinerea</i>

Botrytis cinerea, a highly successful necrotrophic fungal plant pathogen, demonstrates a remarkably broad host range, yet the precise factors governing its host specificity and its ability to coexist non-pathogenically with plants remain unclear. This study systematically assessed host preference in a series of B. cinerea agricultural isolates, revealing a degree of host preference and reduced necrotrophy on "non-hosts". Examining which factors affect these observed host preferences, we identified leaf structure and cytokinin (CK) content as key factors in host recognition. Investigating non-pathogenic B. cinerea-plant interactions, we found that B. cinerea can induce cellular immunity and broad-spectrum disease resistance, with some isolates promoting plant growth and productivity. B. cinerea induced immunity primarily required the salicylic acid (SA) and ethylene (ET) pathways in the host plant. Our findings provide empirical insights into B. cinerea's host adaptation and lifestyle versatility, highlighting a beneficial aspect of its interaction with plants, which could inform environmentally friendly disease control strategies.