The chitin deacetylase TlCDA from Tilletia laevis facilitates pathogen infection by suppressing plant immunity

Common bunt of wheat, caused by Tilletia laevis Kühn, is one of the most devastating wheat diseases worldwide, prevalent in wheat-growing regions across the globe. Diseased wheat grains are replaced by galls and emit a fishy odor, seriously affecting the yield and quality of flour. In this study, TlCDA was identified from T. laevis and shown to possess chitin deacetylase activity, which is upregulated during the early infection stage of T. laevis in wheat. Transient expression of Tl CDA inhibited programmed cell death, suppressed the accumulation of reactive oxygen species, and reduced the expression level of defense-related genes in Nicotiana benthamiana , indicating that Tl CDA can promote the infection of T. laevis by inhibiting immune defense response in plants. Deletion of Tl CDA suppressed the growth and pathogenicity of T. laevis , highlighting the significance of Tl CDA in the host–pathogen interaction. Moreover, Tl CDA can protect teliospores in T. laevis from being damaged by chitinase in vitro. Collectively, these findings identify TlCDA as a key virulence factor of T. laevis and a promising target for chemical control of common bunt.