State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, Engineering Research Center of Grassland Industry, Ministry of Education, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, People's Republic of China.
J Agric Food Chem. 2024 Jun 26;72(25):14448-14465. doi: 10.1021/acs.jafc.4c02472. Epub 2024 Jun 12.
Alfalfa ( subsp. ), the "queen of forage," is the most important perennial legume, with high productivity and an excellent nutritional profile. subsp. is a subspecies of the alfalfa complex and exhibits better drought tolerance. However, drought stress significantly hampers their development and yield. The molecular mechanisms underlying the aboveground and underground tissues of and responding to drought stress remain obscure. Here, we performed a comprehensive comparative analysis of the physiological and transcriptomic responses of and under drought stress. The results showed that photosynthesis was inhibited, and antioxidant enzymes were activated under drought stress. , a CCCH-type zinc finger protein, was identified as a hub gene through weighted gene coexpression network analysis (WGCNA) and was significantly induced by drought in underground tissue. The MsC3H29 protein was localized in the nucleus. Overexpression (OE) of can increase the primary root length and fresh weight of transgenic alfalfa hairy roots, while RNA interference (RNAi) decreases them under drought stress. The 2',7'-dichlorodihydrofluorescein diacetate (HDCFDA) staining revealed that promoted drought tolerance of alfalfa hairy roots through decreasing ROS accumulation. The targeted metabolome analysis showed that the overexpression of resulted in higher levels of accumulation for flavonoid monomers, including vicenin, daidzein, apigenin, isorhamnetin, quercetin, and tricin, in transgenic alfalfa hairy roots before and after drought stress, while RNAi led to a reduction. Our study provided a key candidate gene for molecular breeding to improve drought resistance in alfalfa.
紫花苜蓿（亚种），“牧草之王”，是最重要的多年生豆科植物，具有高产和优良的营养特性。亚种是紫花苜蓿复合体的一个亚种，表现出更好的耐旱性。然而，干旱胁迫严重阻碍了它们的生长和产量。紫花苜蓿地上和地下组织对干旱胁迫的反应的分子机制尚不清楚。在这里，我们对紫花苜蓿和紫花苜蓿在干旱胁迫下的生理和转录组响应进行了全面的比较分析。结果表明，光合作用受到抑制，抗氧化酶被激活。通过加权基因共表达网络分析（WGCNA），发现一个 CCCH 型锌指蛋白作为一个枢纽基因，在地下组织中受到干旱的显著诱导。MsC3H29 蛋白定位于细胞核。过表达（OE）可以增加转基因紫花苜蓿毛状根的主根长和鲜重，而 RNA 干扰（RNAi）则在干旱胁迫下降低它们的长度。2'，7'-二氯二氢荧光素二乙酸酯（HDCFDA）染色表明，通过减少 ROS 积累，促进了紫花苜蓿毛状根的耐旱性。靶向代谢组分析表明，过表达导致转基因紫花苜蓿毛状根在干旱胁迫前后黄酮单体的积累水平升高，包括 vicenin、大豆苷、芹菜素、异鼠李素、槲皮素和木犀草素，而 RNAi 则导致积累减少。我们的研究为提高紫花苜蓿抗旱性的分子育种提供了一个关键候选基因。
