Identification and Functional Analysis of Family Genes Associated with Salt Stress in Rice.

Salinity stress has a great impact on crop growth and productivity and is one of the major factors responsible for crop yield losses. The K-homologous (KH) family proteins play vital roles in regulating plant development and responding to abiotic stress in plants. However, the systematic characterization of the family in rice is still lacking. In this study, we performed genome-wide identification and functional analysis of family genes and identified a total of 31 genes in rice. According to the homologs of genes in , we constructed a phylogenetic tree with 61 genes containing 31 genes in and 30 genes in and separated them into three major groups. In silico tissue expression analysis showed that the genes are constitutively expressed. The qRT-PCR results revealed that eight genes responded strongly to salt stresses, and exhibited the strongest decrease in expression level, which was selected for further study. We generated the mutant via the CRISPR/Cas9 genome-editing method. Further stress treatment and biochemical assays confirmed that mutant was more salt-sensitive than Nip and the expression of several key salt-tolerant genes in was significantly reduced. Taken together, our results shed light on the understanding of the family and provide a theoretical basis for future abiotic stress studies in rice.