Table_4_Genome-wide analysis of the Thaumatin-like gene family in Qingke (Hordeum vulgare L. var. nudum) uncovers candidates involved in plant defense against biotic and abiotic stresses.DOCX

Thaumatin-like proteins (TLPs) participate in the defense responses of plants as well as their growth and development processes, including seed germination. Yet the functioning of TLP family genes, in addition to key details of their encoded protein products, has not been thoroughly investigated for Qingke (Hordeum vulgare L. var. nudum). Here, a total of 36 TLP genes were identified in the genome of Qingke via HMM profiling. Of them, 25 TLPs contained a signal peptide at the N-terminus, with most proteins predicted to localize in the cytoplasm or outer membrane. Sequence alignment and motif analysis revealed that the five REDDD residues required for β-1,3-glucanase activity were conserved in 21 of the 36 Qingke TLPs. Phylogenetically, the TLPs in plants are clustered in 10 major groups. Our analysis of gene structure did not detect an intron in 15 Qingke TLPs whereas the other 21 did contain 1–7 introns. A diverse set of cis-acting motifs were found in the promoters of the 36 TLPs, including elements related to light, hormone, and stress responses, growth and development, circadian control, and binding sites of transcription factors, thus suggesting a multifaceted role of TLPs in Qingke. Expression analyses revealed the potential involvement of TLPs in plant defense against biotic and abiotic stresses. Taken together, the findings of this study deepen our understanding of the TLP family genes in Qingke, a staple food item in Tibet, which could strengthen future investigations of protein function in barley and its improved genetic engineering.

类甜蛋白（Thaumatin-like proteins, TLPs）参与植物的防御应答过程，同时调控植物生长发育进程，包括种子萌发环节。然而，目前针对青稞（Hordeum vulgare L. var. nudum）的TLP家族基因功能及其编码蛋白产物的关键细节，尚未得到全面深入的研究。本研究通过隐马尔可夫模型（HMM）谱分析，在青稞基因组中共鉴定出36个TLP基因。其中25个TLP蛋白在N端含有信号肽，预测的多数蛋白定位于细胞质或外膜。序列比对与基序分析结果显示，36个青稞TLP中有21个保留了β-1,3-葡聚糖酶活性所需的5个REDDD氨基酸残基。系统发育分析表明，植物TLP家族蛋白可分为10个主要进化簇。基因结构分析显示，15个青稞TLP基因不含内含子，其余21个则含有1至7个不等的内含子。在36个TLP基因的启动子区域，我们发现了多样的顺式作用元件，包括与光响应、激素响应、胁迫应答、生长发育、昼夜节律调控相关的元件，以及转录因子结合位点，这表明TLP在青稞中发挥多方面的调控功能。表达谱分析结果显示，TLP可能参与青稞对生物胁迫与非生物胁迫的防御过程。综上，本研究结果加深了我们对作为西藏主食作物的青稞TLP家族基因的认知，可为后续大麦蛋白功能研究及遗传改良工程提供理论支撑。