Investigation of evolutionary and expressional relationships in the function of the leucine-rich repeat receptor-like protein kinase gene family (LRR-RLK) in the radish (Raphanus sativus L.).

The leucine-rich repeat receptor-like protein kinase (LRR-RLK) plays an important role in plant development and disease defence. Although genome-wide studies of LRR-RLKs have been performed in several species, a comprehensive analysis, including evolutionary, structural and expressional analyses and their relationships to function, has not been carried out in the radish (Raphanus sativus L.). In this study, we identified 292 LRR-RLK genes in the R. sativus genome and classified them into 23 subgroups. The subgroups containing genes involved in defence were more likely to evolve from tandem duplication rather than whole genome triplication (WGT), had lower expression profiles and were expressed in fewer tissues than the subgroups related to development. Gene structures and conserved domains did not differ in the defence-related or development-related subgroups, but they were distinct in each subgroup. This study sheds light on the evolutionary and expressional relationships with the functions of R. sativus LRR-RLKs and provides an integrated framework for additional investigation into these functions.