Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China; College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, 310058, China.
College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, 310058, China.
Plant Physiol Biochem. 2024 Nov;216:109171. doi: 10.1016/j.plaphy.2024.109171. Epub 2024 Oct 5.
The projected increase in drought severity and duration worldwide poses a significant threat to crop growth and sustainable food production. Xyloglucan endotransglucosylase/hydrolases (XTHs) family is essential in cell wall modification through the construction and restructuring of xyloglucan cross-links, but their role in drought tolerance and stomatal regulation is still illusive. We cloned and functionally characterized HvXTH1 using genetic, physiological, biochemical, transcriptomic and metabolomic approaches in barley. Evolutionary bioinformatics showed that orthologues of XTH1 was originated from Streptophyte algae (e.g. some species in the Zygnematales) the closest clade to land plants based on OneKP database. HvXTH1 is highly expressed in leaves and HvXTH1 is localized to the plasma membrane. Under drought conditions, silencing HvXTH1 in drought-tolerant Tibetan wild barley XZ5 induced a significant reduction in water loss rate and increase in biomass, however overexpressing HvXTH1 exhibited drought sensitivity with significantly less drought-responsive stomata, lower lignin content and a thicker cell wall. Transcriptome profile of the wild type Golden Promise and HvXTH1-OX demonstrated that drought-induced differentially expressed genes in leaves are related to cell wall biosynthesis, abscisic acid and stomatal signaling, and stress response. Furthermore, overexpressing HvXTH1 suppressed both genes and metabolites in the phenylpropanoid pathway for lignin biosynthesis, leading to drought sensitivity of HvXTH1-OX. We provide new insight by deciphering the function of a novel protein HvXTH1 for drought tolerance in cell wall modification, stomatal regulation, and phenylpropanoid pathway for lignin biosynthesis in barley. The function of HvXTH1 in drought response will be beneficial to develop crop varieties adapted to drought.
预计全球干旱严重程度和持续时间的增加将对作物生长和可持续粮食生产构成重大威胁。木葡聚糖内转糖基酶/水解酶（XTHs）家族通过构建和重构木葡聚糖交联在细胞壁修饰中至关重要，但它们在耐旱性和气孔调节中的作用仍不清楚。我们使用遗传、生理、生化、转录组学和代谢组学方法在大麦中克隆并功能表征了 HvXTH1。进化生物信息学显示，XTH1 的同源物起源于 Streptophyte 藻类（例如，某些 Zygnematales 物种），是基于 OneKP 数据库的与陆地植物最接近的类群。HvXTH1 在叶片中高度表达，HvXTH1 定位于质膜。在干旱条件下，耐旱西藏野生大麦 XZ5 中的 HvXTH1 沉默会导致水分流失率显著降低和生物量增加，但 HvXTH1 的过表达表现出对干旱的敏感性，其气孔对干旱的响应明显减少，木质素含量降低，细胞壁变厚。野生型 Golden Promise 和 HvXTH1-OX 的转录组谱表明，叶片中干旱诱导的差异表达基因与细胞壁生物合成、脱落酸和气孔信号转导以及应激反应有关。此外，HvXTH1 的过表达抑制了木质素生物合成中苯丙烷途径的基因和代谢物，导致 HvXTH1-OX 对干旱敏感。我们通过揭示一种新型蛋白 HvXTH1 在细胞壁修饰、气孔调节以及木质素生物合成的苯丙烷途径中的耐旱功能，为大麦耐旱性提供了新的见解。HvXTH1 在干旱响应中的功能将有助于开发适应干旱的作物品种。
