Ndombi Salome Njeri, Chen Yiwen, Gao Qinqin, Jiang Jie, Shen Qiang, Ma Yuanchun, Fang Wanping, Zhu Xujun
College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
Tea Research Institute, Guizhou Provincial Academy of Agricultural Sciences, Guiyang, 417100, China.
Plant Physiol Biochem. 2025 Jun 13;227:110158. doi: 10.1016/j.plaphy.2025.110158.
Drought is a major abiotic stressor that threatens global agriculture. Thus, it is imperative to unravel the molecular processes that underlie plant drought resistance. UDP-glycosyltransferases (UGTs), also known as family 1 glycosyltransferases, are essential for plant growth and development, stress responses, and other physiological processes. The precise physiological functions of numerous UGT members in response to plant abiotic stressors remain largely unclear, despite their significance. A novel glycosyltransferase (CsUGT87A1) has been discovered in tea plants, a significant economic crop, according to this study. This gene's expression is significantly upregulated under drought stress conditions. CsUGT87A1 is predominantly expressed in the roots, and its protein is located in the cell nucleus. Enzyme activity tests demonstrated that the recombinant CsUGT87A1 (rCsUGT87A1) showed catalytic activity when indole-3-acetic acid (IAA) was used as a substrate in vitro. Downregulating the CsUGT87A1 gene, using the anti-sense oligonucleotide (ASO) gene silencing technology, significantly decreased drought resistance and lowered IAA levels in tea plant seedlings. Furthermore, there was a notable rise in IAA in Arabidopsis when CsUGT87A1 was expressed heterologously. Increases in seed germination rate, root length, chlorophyll and photosynthetic parameters, proline, and antioxidant activities, as well as a drop in ROS and MDA levels as compared to EV lines, all demonstrated a significant improvement in drought resistance in the transgenic Arabidopsis. Collectively, our findings indicate that CsUGT87A1 may act as a positive regulator of IAA biosynthesis in response to drought stress in plants. Our results enrich the roles of auxin glycosyltransferases in drought tolerance of plants and laid a foundation for cultivating transgenic crops with higher resistance to water stress.
干旱是威胁全球农业的主要非生物胁迫因素。因此，揭示植物抗旱的分子机制势在必行。UDP-糖基转移酶（UGTs），也称为1家族糖基转移酶，对植物生长发育、胁迫反应及其他生理过程至关重要。尽管众多UGT成员意义重大，但其在植物应对非生物胁迫时的确切生理功能仍不清楚。根据本研究，在重要经济作物茶树中发现了一种新型糖基转移酶（CsUGT87A1）。该基因在干旱胁迫条件下表达显著上调。CsUGT87A1主要在根中表达，其蛋白位于细胞核中。酶活性测试表明，体外以吲哚-3-乙酸（IAA）为底物时，重组CsUGT87A1（rCsUGT87A1）具有催化活性。利用反义寡核苷酸（ASO）基因沉默技术下调CsUGT87A1基因，显著降低了茶树幼苗的抗旱性并降低了IAA水平。此外，在拟南芥中异源表达CsUGT87A1时，IAA显著增加。与空载体株系相比，转基因拟南芥种子发芽率、根长、叶绿素和光合参数、脯氨酸及抗氧化活性增加，ROS和MDA水平下降，所有这些都表明抗旱性有显著提高。总体而言，我们的研究结果表明，CsUGT87A1可能作为植物干旱胁迫下IAA生物合成的正调控因子。我们的结果丰富了生长素糖基转移酶在植物耐旱性中的作用，为培育具有更高水分胁迫抗性的转基因作物奠定了基础。
