In Silico Identification of the Full Complement of Subtilase-Encoding Genes and Characterization of the Role of in Resistance Against Stripe Rust in Wheat.

Plant subtilases (SBTs) or subtilisin-like proteases comprise a very diverse family of serine peptidases that participates in a broad spectrum of biological functions. Despite increasing evidence for roles of SBTs in plant immunity in recent years, little is known about wheat () SBTs (TaSBTs). Here, we identified 255 genes from bread wheat using the latest version 2.0 of the reference genome sequence. The SBT family can be grouped into five clades, from TaSBT1 to TaSBT5, based on a phylogenetic tree constructed with deduced protein sequences. In silico protein-domain analysis revealed the existence of considerable sequence diversification of the TaSBT family which, together with the local clustered gene distribution, suggests that genes have undergone extensive functional diversification. Among those genes whose expression was altered by biotic factors, was found to be induced in wheat leaves by chitin and flg22 elicitors, as well as six examined pathogens, implying a role for in plant defense. Transient overexpression of in leaves resulted in necrotic cell death. Moreover, knocking down in wheat using barley stripe mosaic virus-induced gene silencing compromised the hypersensitive response and resistance against f. sp. , the causal agent of wheat stripe rust. Taken together, this study defined the full complement of wheat genes and provided evidence for a positive role of one particular member, , in the incompatible interaction between wheat and a stripe rust pathogen.