Table_6_Genome-Wide Analysis of CqCrRLK1L and CqRALF Gene Families in Chenopodium quinoa and Their Roles in Salt Stress Response.XLSX

Chenopodium quinoa 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 Arabidopsis thaliana, Catharanthus roseus receptor-like kinase (CrRLK1Ls) 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 CqCrRLK1L and 18 CqRALF family genes in quinoa genome. Transcriptomic profiling of the leaf, root, stamen, and pistil tissues of quinoa reveals that different CqCrRLK1L and CqRALF genes exhibit tissue-specific expression patterns, which is consistent with that observed in other plant species. RNA-seq data show that three CqCrRLK1L genes are highly up-regulated after salt treatment, suggesting that some CqCrRLK1L family genes are transcriptionally responsive to salt stress in quinoa. Biochemical study indicates that CqRALF15, a paralog of Arabidopsis RALF22, is physically associated with CrRLK1L 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 CqRALF15 in Arabidopsis results in enhanced leaf bleaching under salt stress, indicating that CqRALF15 is involved in salt stress response. Together, our study characterizes CqCrRLK1L and CqRALF family genes in quinoa at genomic, transcriptional, and protein levels, and provides evidence to support their roles in salt stress response.

藜麦（Chenopodium quinoa）是一种盐生植物，兼具卓越的营养品质，因此有望成为盐碱地种植的理想作物——不仅可应对土地盐碱化问题，还能为人类健康提供优质营养食品。目前，藜麦耐盐的分子机制仍未完全阐明。在拟南芥（Arabidopsis thaliana）中，长春花类受体激酶（Catharanthus roseus receptor-like kinase, CrRLK1Ls）家族成员FERONIA（FER）及其配体快速碱化因子（rapid alkalinization factors, RALFs）已被报道参与盐胁迫耐受的调控。本研究对藜麦基因组开展全基因组分析，共鉴定到26个CqCrRLK1L家族基因与18个CqRALF家族基因。对藜麦叶片、根、雄蕊以及雌蕊组织的转录组分析显示，不同CqCrRLK1L与CqRALF基因呈现出组织特异性表达模式，这一结果与其他植物物种中的报道一致。RNA测序（RNA-seq）数据表明，3个CqCrRLK1L基因在盐处理后显著上调表达，提示部分CqCrRLK1L家族基因在藜麦中对盐胁迫存在转录响应。生化实验证实，拟南芥RALF22的旁系同源基因CqRALF15可与CrRLK1L家族蛋白CqFER及AtFER发生物理互作。CqRALF15与AtRALF22在诱导AtFER内化以及抑制藜麦和拟南芥根系生长方面功能保守。此外，在拟南芥中过表达CqRALF15会导致盐胁迫下叶片褪绿程度加剧，表明CqRALF15参与盐胁迫响应过程。综上，本研究从基因组、转录组以及蛋白质层面系统解析了藜麦CqCrRLK1L与CqRALF家族基因，并为其在盐胁迫响应中的作用提供了实验证据。