Genome-wide identification and characterization of OsDGK gene family in rice and expression patterns under salt stress

Diacylglycerol kinase (DGK) functions as the indispensable enzyme in phosphatidic acid (PA) synthesis pathway, which is associated with plant growth regulation as well as stress adaptation. However, the genomic architecture and expression patterns of the OsDGK gene family remain unclear. Our work identified 14 OsDGK genes in the whole-genome of rice. Phylogenetic analysis suggested that DGKs in rice, Arabidopsis , potato, and maize were classified into four evolutionary clades. Gene duplication events occurred in OsDGK1 and OsDGK2 , while OsDGK3 and OsDGK12 showed collinearity relationship with other species. The cis-acting elements and interacting proteins laid the genetic foundation for OsDGK genes to participate in stress response and secondary metabolites synthesis. Transcriptome data confirmed the expression specificity of OsDGK genes in diverse tissues and at different time after salt stress. Quantitative real-time polymerase chain reaction (qRT-PCR) showed that all of 14 OsDGK genes were associated with salt stress response pathway, while OsDGK5 and OsDGK8 were probably involved in signal transduction. Furthermore, we knocked out OsDGK10 gene and found the loss-of-function of OsDGK10 compromised salt stress tolerance of rice. In summary, this study identified the OsDGK gene family and preliminarily elucidated the positive function of OsDGK genes in regulating salt stress response, which may accelerate the molecular breeding process of salt-tolerant rice varieties.