Genome-wide identification and biochemical characterization of glycoside hydrolase gene family members in Tilletia Horrida

Rice kernel smut, caused by Tilletia horrida, is becoming an increasingly serious disease in hybrid rice planting, leading to production losses and quality decline of male-sterile rice varieties. Successful infection requires an efficient energy source that the pathogen obtains from rice plants, such as carbohydrates. Glycoside hydrolases (GHs), one of the largest sub-families in the cell wall-degrading enzyme family, play a key role in the infection progress of pathogens. To investigate their roles in facilitating infection, in this study, we identified and characterized genes encoding GH family proteins of T. horrida and further explored the functions and structures of these genes.

Through genome-wide sequencing and bioinformatics analyses, 52 GH genes were identified from T. horrida, named ThGhd_1 to ThGhd_52. The subcellular location, conserved motifs, and structures of ThGhds were identified by bioinformatics analyses.

Phylogenetic analysis revealed that ThGhds with similar domains clustered together, although some proteins clustered in different branches, which might reflect functional diversity. Protein-protein interaction network analysis revealed that ThGhds interact with partner proteins involved in reactive oxygen species signaling, protein kinase activity, and plant hormone signal transduction pathways. RNA-sequencing analysis showed that the expression of ThGhd genes responded differently at different infection time points, with dynamic changes detected during the T. horrida infection process, indicating that these genes are involved in interactions with rice and have potential roles in pathogenic mechanisms.

The results of this study provide valuable resources for the structure elucidation of GH family proteins of T. horrida and can help to further elucidate their roles in pathogenesis.