Genome-wide identification and evolution of WNK kinases in Bambusoideae and transcriptional profiling during abiotic stress in .

With-no-lysine (WNK) kinases play vital roles in abiotic stress response, circadian rhythms, and regulation of flowering time in rice, Arabidopsis, and Glycine max. However, there are no previous reports of WNKs in the Bambusoideae, although genome sequences are available for diploid, tetraploid, and hexaploid bamboo species. In the present study, we identified 41 genes in five bamboo species and analysed gene evolution, phylogenetic relationship, physical and chemical properties, -elements, and conserved motifs. We predicted the structure of PeWNK proteins of moso bamboo and determined the exposed, buried, structural and functional amino acids. Real-time qPCR analysis revealed that , , , and genes are involved in circadian rhythms. Analysis of gene expression of different organs at different developmental stages revealed that genes are tissue-specific. Analysis of various abiotic stress transcriptome data (drought, salt, SA, and ABA) revealed significant gene expression levels in all except . In particular, and were significantly down- and up-regulated, respectively, after abiotic stress treatment. A co-expression network of genes also showed that , , , and were co-expressed with transcriptional regulators related to abiotic stress. In conclusion, our study identified the of moso bamboo involved in circadian rhythms and abiotic stress response. In addition, this study serves as a guide for future functional genomic studies of the genes of the Bambusoideae.