Li Zhi-Ang, Fahad Muhammad, Li Wan-Chang, Tariq Leeza, Liu Miao-Miao, Liu Ya-Nan, Wang Tai-Xia
College of Life Sciences, Henan Normal University, Xinxiang 453007, China.
Zhejiang Provincial Key Laboratory of Crop Genetic Resources, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
Plants (Basel). 2024 Sep 20;13(18):2628. doi: 10.3390/plants13182628.
Phytohormones are vital for developmental processes, from organ initiation to senescence, and are key regulators of growth, development, and photosynthesis. In natural environments, plants often experience high light (HL) intensities coupled with elevated temperatures, which pose significant threats to agricultural production. However, the response of phytohormone-related genes to long-term HL exposure remains unclear. Here, we examined the expression levels of genes involved in the biosynthesis of ten phytohormones, including gibberellins, cytokinins, salicylic acid, jasmonic acid, abscisic acid, brassinosteroids, indole-3-acetic acid, strigolactones, nitric oxide, and ethylene, in two winter wheat cultivars, Xiaoyan 54 (XY54, HL tolerant) and Jing 411 (J411, HL sensitive), when transferred from low light to HL for 2-8 days. Under HL, most genes were markedly inhibited, while a few, such as , , , and , were induced in both varieties. Interestingly, and expression positively correlated with sugar content but negatively with chlorophyll content and expression. In addition, we observed that both varieties experienced a sharp decline in chlorophyll content and photosynthesis performance after prolonged HL exposure, with J411 showing significantly more sensitivity than XY54. Hierarchical clustering analysis classified the phytohormone genes into the following three groups: Group 1 included six genes highly expressed in J411; Group 2 contained 25 genes drastically suppressed by HL in both varieties; and Group 3 contained three genes highly expressed in XY54. Notably, abscisic acid (ABA), and jasmonic acid (JA) biosynthesis genes and their content were significantly higher, while gibberellins (GA) content was lower in XY54 than J411. Together, these results suggest that the differential expression and content of GA, ABA, and JA play crucial roles in the contrasting responses of tolerant and sensitive wheat cultivars to leaf senescence induced by long-term HL. This study enhances our understanding of the mechanisms underlying HL tolerance in wheat and can guide the development of more resilient wheat varieties.
植物激素对于从器官起始到衰老的发育过程至关重要，是生长、发育和光合作用的关键调节因子。在自然环境中，植物常常遭遇高光（HL）强度并伴有温度升高的情况，这对农业生产构成重大威胁。然而，植物激素相关基因对长期高光照射的反应仍不清楚。在此，我们检测了两个冬小麦品种，小偃54（XY54，耐高光）和京411（J411，高光敏感），在从弱光转移到高光2 - 8天后，参与十种植物激素生物合成的基因的表达水平，这十种植物激素包括赤霉素、细胞分裂素、水杨酸、茉莉酸、脱落酸、油菜素内酯、吲哚 - 3 - 乙酸、独脚金内酯、一氧化氮和乙烯。在高光条件下，大多数基因受到显著抑制，而少数基因，如 、 、 和 ，在两个品种中均被诱导。有趣的是， 和 的表达与糖分含量呈正相关，但与叶绿素含量和 的表达呈负相关。此外，我们观察到两个品种在长时间高光照射后叶绿素含量和光合作用性能均急剧下降，J411表现出比XY54明显更高的敏感性。层次聚类分析将植物激素基因分为以下三组：第1组包括在J411中高表达的六个基因；第2组包含在两个品种中均被高光强烈抑制的25个基因；第3组包含在XY54中高表达的三个基因。值得注意的是，XY54中脱落酸（ABA）和茉莉酸（JA）的生物合成基因及其含量显著高于J411，而赤霉素（GA）含量则低于J411。综上所述，这些结果表明GA、ABA和JA的差异表达及含量在耐高光和高光敏感小麦品种对长期高光诱导的叶片衰老的不同反应中起关键作用。本研究增进了我们对小麦耐高光机制的理解，并可为培育更具抗逆性的小麦品种提供指导。
