Table_7_Small secreted peptides encoded on the wheat (triticum aestivum L.) genome and their potential roles in stress responses.xlsx

Small secreted peptides (SSPs) are important signals for cell-to-cell communication in plant, involved in a variety of growth and developmental processes, as well as responses to stresses. While a large number of SSPs have been identified and characterized in various plant species, little is known about SSPs in wheat, one of the most important cereal crops. In this study, 4,981 putative SSPs were identified on the wheat genome, among which 1,790 TaSSPs were grouped into 38 known SSP families. The result also suggested that a large number of the putaitive wheat SSPs, Cys-rich peptides in particular, remained to be characterized. Several TaSSP genes were found to encode multiple SSP domains, including CLE, HEVEIN and HAIRPININ domains, and two potentially novel TaSSP family DYY and CRP8CI were identified manually among unpredicted TaSSPs. Analysis on the transcriptomic data showed that a great proportion of TaSSPs were expressed in response to abiotic stresses. Exogenous application of the TaCEPID peptide encoded by TraesCS1D02G130700 enhanced the tolerance of wheat plants to drought and salinity, suggesting porential roles of SSPs in regulating stress responses in wheat.

小分泌肽（Small Secreted Peptides, SSPs）是植物细胞间通讯的关键信号分子，参与多种生长发育进程以及胁迫响应。尽管已在多种植物物种中鉴定并表征了大量SSPs，但作为最重要谷类作物之一的小麦，其体内SSPs的相关研究仍较为匮乏。本研究从小麦基因组中鉴定出4981个推定SSPs，其中1790个TaSSPs被归类至38个已知SSP家族。研究结果同时显示，大量推定的小麦SSPs，尤其是富含半胱氨酸的肽类，仍有待进一步表征。本研究发现，多个TaSSP基因可编码多个SSP结构域，包括CLE、HEVEIN以及HAIRPININ结构域；此外，还通过人工筛查在未被预测的TaSSPs中鉴定出两个潜在新型TaSSP家族：DYY和CRP8CI。转录组数据分析表明，大部分TaSSPs的表达会响应非生物胁迫。外源施加由TraesCS1D02G130700基因编码的TaCEPID肽，可提升小麦植株的干旱与盐胁迫耐受性，这提示SSPs在小麦胁迫响应调控中具备潜在功能。