Dong Guangrui, Ma Yuqing, Zhao Shuman, Ma Xinmei, Liu Chonglin, Ding Yi, Wu Jiarun, Hou Bingkai
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, Shandong Key Laboratory of Precision Molecular Crop Design and Breeding, School of Life Sciences, Shandong University, Qingdao 266237, China.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, Shandong Key Laboratory of Precision Molecular Crop Design and Breeding, School of Life Sciences, Shandong University, Qingdao 266237, China.
Plant Sci. 2025 Nov;360:112692. doi: 10.1016/j.plantsci.2025.112692. Epub 2025 Jul 31.
UDP-glycosyltransferase (UGT) constitute a superfamily and get dramatic expansion during evolution of land plants. However, their biological significances in stress responses are largely unclear. In addition, it is well known that accumulation of flavonoids enable plants to cope with stressful environments, but the molecular mechanism underlying metabolism regulation of flavonoids under stress conditions remains unanswered. Here, we analyzed the impact of a rice UGT gene, DUGT2, on flavonoid metabolism under stress conditions by using genetic, biochemical, molecular, and omics methods. We found that overexpression of DUGT2 enhanced plant tolerance to drought and salt, while DUGT2 knockout mutants showed a more sensitive phenotype. Our metabolomics analysis showed that the mutants had the most significant reduction in flavonoids under stress conditions compared to the wild type. Subsequent biochemical analysis verified a broad-spectrum enzyme activity of DUGT2 toward flavonoids, suggesting that DUGT2 can affect flavonoid metabolism by flavonoid glycosylation. Furthermore, our transcriptome analysis revealed that the loss of DUGT2 function led to a significant decrease in the expression of genes related to flavonoid biosynthesis and antioxidant enzymes, which might be achieved through feedback regulation. Moreover, we identified an upstream regulator, bZIP16, and demonstrated its positive regulation on DUGT2 transcription activity. Overall, this work reveals that DUGT2 could enhance abiotic stress tolerance by the glycosylation-promoted flavonoid metabolism under the regulation of bZIP16. This work can not only help to understand the biological functions of UGT superfamily in stress responses, but also get a new insight into the regulation mechanism of flavonoid metabolism, especially under stress conditions.
尿苷二磷酸糖基转移酶（UGT）构成一个超家族，在陆地植物进化过程中经历了显著扩张。然而，它们在应激反应中的生物学意义在很大程度上尚不清楚。此外，众所周知，黄酮类化合物的积累使植物能够应对胁迫环境，但胁迫条件下黄酮类化合物代谢调控的分子机制仍未得到解答。在这里，我们通过遗传、生化、分子和组学方法分析了水稻UGT基因DUGT2在胁迫条件下对黄酮类化合物代谢的影响。我们发现，DUGT2的过表达增强了植物对干旱和盐的耐受性，而DUGT2基因敲除突变体表现出更敏感的表型。我们的代谢组学分析表明，与野生型相比，突变体在胁迫条件下黄酮类化合物的减少最为显著。随后的生化分析证实了DUGT2对黄酮类化合物具有广谱酶活性，表明DUGT2可以通过黄酮类糖基化影响黄酮类化合物代谢。此外，我们的转录组分析表明，DUGT2功能的丧失导致与黄酮类生物合成和抗氧化酶相关基因表达的显著下降，这可能是通过反馈调节实现的。此外，我们鉴定了一个上游调节因子bZIP16，并证明了它对DUGT2转录活性的正向调节作用。总体而言，这项工作揭示了DUGT2可以在bZIP16的调控下通过糖基化促进的黄酮类化合物代谢增强非生物胁迫耐受性。这项工作不仅有助于理解UGT超家族在应激反应中的生物学功能，还能为黄酮类化合物代谢的调控机制，特别是在胁迫条件下的调控机制提供新的见解。
