Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Wuhan 430070, China; Micro-Element Research Center, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan 430070, Hubei Province, China.
Department of Agronomy, University of Agriculture, Faisalābād, Punjab 38000, Pakistan.
Ecotoxicol Environ Saf. 2018 Nov 30;164:589-596. doi: 10.1016/j.ecoenv.2018.08.062. Epub 2018 Aug 24.
Most plants exhibit strong tolerance to excess molybdenum (Mo). However, the metabolic profile and tolerance mechanisms of plants in response to excess Mo remain unknown. We comprehensively analyzed changes in the metabolic profiles of leaves and roots in soybean (Glycine max L.) seedlings cultured under normal-Mo and excess-Mo conditions by using ultra performance liquid chromatography (UPLC) combined with MS/MS (mass spectrometry). There were 42 differential metabolites in the roots and 19 differential metabolites in the leaves in response to excess Mo stress. In roots, the organic acids, levels of gluconic acid, D-glucarate and citric acid increased by 107.63-, 4.42- and 2.87-folds after excess Mo exposure. Several hormones (salicylic acid, jasmonic acid) and lipids (PG, MG, DG etc) also increased significantly under excess Mo condition. Metabolites related to ascorbate-glutathione metabolism and flavonoid and isoflavone biosynthesis notably accumulated in roots. Only lipid metabolism and salicylic acid accumulation were induced in leaves under excess Mo stress. It is speculated that organic compounds such as 2-oxoarginine, L-nicotine, gluconic acid, D-glucurate, and citric acid played important roles to chelate Mo and reduce its toxicity. Signaling molecules (JA, SA, and some lipids) and non-enzyme antioxidants such as flavonoids/isoflavones act synergistically to detoxify ROS and contribute to Mo tolerance in soybean seedlings. More metabolic pathways were induced by Mo excess in roots than in leaves, suggesting that roots play more implant role in Mo tolerance.
大多数植物对过量钼（Mo）表现出很强的耐受性。然而，植物对过量 Mo 的代谢特征和耐受机制仍不清楚。我们通过超高效液相色谱（UPLC）与 MS/MS（质谱）联用，全面分析了正常 Mo 和过量 Mo 条件下培养的大豆（Glycine max L.）幼苗叶片和根系代谢谱的变化。过量 Mo 胁迫下，根系中有 42 个差异代谢物，叶片中有 19 个差异代谢物。在根系中，葡萄糖酸、D-葡萄糖醛酸和柠檬酸的水平分别增加了 107.63、4.42 和 2.87 倍。几种激素（水杨酸、茉莉酸）和脂类（PG、MG、DG 等）在过量 Mo 条件下也显著增加。与抗坏血酸-谷胱甘肽代谢和类黄酮和异黄酮生物合成相关的代谢物在根系中明显积累。只有在过量 Mo 胁迫下，叶片中的脂类代谢和水杨酸积累被诱导。推测 2-氧代精氨酸、L-烟碱、葡萄糖酸、D-葡萄糖醛酸和柠檬酸等有机化合物在螯合 Mo 和降低其毒性方面发挥了重要作用。信号分子（JA、SA 和一些脂类）和非酶抗氧化剂（如类黄酮/异黄酮）协同作用，以清除 ROS，并有助于大豆幼苗对 Mo 的耐受。过量 Mo 在根系中诱导的代谢途径比在叶片中多，这表明根系在 Mo 耐受中起着更重要的作用。
