Functional Analyses of a Small Secreted Cysteine-Rich Protein ThSCSP_14 in .

is a biotrophic basidiomycete fungus that causes rice kernel smut, one of the most significant diseases in hybrid rice-growing areas worldwide. Little is known about the pathogenic mechanisms and functions of effectors in . Here, we performed functional studies of the effectors in and found that, of six putative effectors tested, only ThSCSP_14 caused the cell death phenotype in epidermal cells of leaves. ThSCSP_14 was upregulated early on during the infection process, and the encoded protein was secreted. The predicted signal peptide (SP) of ThSCSP_14 was required for its ability to induce the necrosis phenotype. Furthermore, the ability of ThSCSP_14 to trigger cell death in depended on suppressing the G2 allele of Skp1 (SGT1), required for Mla12 resistance (RAR1), heat-shock protein 90 (HSP90), and somatic embryogenesis receptor-like kinase (SERK3). It is important to note that ThSCSP_14 induced a plant defense response in leaves. Hence, these results demonstrate that ThSCSP_14 is a possible effector that plays an essential role in -host interactions.