Genome-Wide Analysis of and Gene Families in and Their Roles in Salt Stress Response.

is a halophyte with exceptional nutritional qualities, and therefore it is potentially an ideal crop to grow in saline soils, not only addressing the problem of land salinization, but also providing nutrient food for the health of humans. Currently, the molecular mechanisms underlying salt tolerance in quinoa are still largely unknown. In , receptor-like kinase (RLK1Ls) FERONIA (FER) and its ligands rapid alkalinization factors (RALFs) have been reported that participate in the regulation of salt tolerance. Here, we performed a genome-wide analysis and identified 26 and 18 family genes in quinoa genome. Transcriptomic profiling of the leaf, root, stamen, and pistil tissues of quinoa reveals that different and genes exhibit tissue-specific expression patterns, which is consistent with that observed in other plant species. RNA-seq data show that three genes are highly up-regulated after salt treatment, suggesting that some family genes are transcriptionally responsive to salt stress in quinoa. Biochemical study indicates that CqRALF15, a paralog of Arabidopsis RALF22, is physically associated with RLK1L proteins CqFER and AtFER. CqRALF15 and AtRALF22 are functionally conserved in inducing the internalization of AtFER and in triggering root growth inhibition in both quinoa and Arabidopsis. Moreover, overexpression of in Arabidopsis results in enhanced leaf bleaching under salt stress, indicating that is involved in salt stress response. Together, our study characterizes and family genes in quinoa at genomic, transcriptional, and protein levels, and provides evidence to support their roles in salt stress response.