SsdchA is a novel secretory cellobiohydrolase driving pathogenicity in Sclerotinia sclerotiorum

The necrotrophic fungus, , employs an array of cell wall-degrading enzymes (CWDEs), including cellulase, to dismantle host cell walls. However, the molecular mechanisms through which degrades cellulose remain elusive. Here, we unveil a novel secretory cellobiohydrolase, SsdchA, characterized by a signal peptide and a Glyco_hydro_7 (GH7) domain. exhibits a robust expression of during early infection stages. Interestingly, colony morphology and growth rates remain unaffected across the wild-type, deletion strains and overexpression strains on potato dextrose agar (PDA) medium. Nevertheless, the pathogenicity and cellobiohydrolase activity decreased in the deletion strains, but enhanced in the overexpression strains. Moreover, the heterologous expression of in leads to reduced cellulose content and heightened susceptibility to . Collectively, our data underscore the pivotal role of the novel cellobiohydrolase SsdchA in the pathogenicity of