Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education/ College of Landscape Architecture, Northeast Forestry University, Harbin, 150040, China.
Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education/ College of Landscape Architecture, Northeast Forestry University, Harbin, 150040, China.
Plant Physiol Biochem. 2024 Dec;217:109231. doi: 10.1016/j.plaphy.2024.109231. Epub 2024 Oct 31.
Root exudates are the most direct performance for plants responding to adverse environments, and are also important media for materials exchange, energy transmission and information communication between the roots and rhizosphere. However, how plant roots and exudates respond to aluminum (Al) stress under elevated CO concentration (eCO) is still unclear. Ricinus communis is a famous oilseed crop throughout the world, which has strong tolerance to metal contaminated soil. In the present study, root physiological changes and the exudates of this species under aluminum stress and eCO based on metabolomic were investigated. The results showed that high Al concentration stress significantly increased aluminum, MDA, proline, and soluble sugar contents, and decreased the dry weights and soluble protein concentration. Furthermore, eCO alleviated the inhibition of root growth under high Al stress by increasing the dry weights, antioxidant enzyme activities and decreasing the MDA content. Collectively, a total of 511 metabolites were detected in the castor exudates of which lipids, organic acids, and organic oxygen compounds occupied 40.82%, 17.78% and 12.54%, respectively. There were 83, 15, and 100 differential metabolites for high Al stress, eCO and the interaction of the two factors compared with the control. 12 differential metabolites were found under eCO and Al stress compared with Al stress alone. Under Al stress, TCA cycle, organic acids, and lipids metabolisms were inhibited; coumarins and carbohydrates conjugates were significantly up-regulated, which may help castor adapt to aluminum-contaminated conditions. Moreover, eCO increased the secretion of organic acids, fatty acyls, and carbohydrates to enhance the antioxidant capacity and root growth of castor under Al stress; eCO enhanced the TCA cycle, organic acids accumulation, lipids metabolism, biosynthesis of amino acids, pentose and glucuronate interconversions, and inhibited DNA oxidative stress of castor roots under Al stress. The present study provides new insights into the crucial role of root exudates in improving Al-tolerance of castor under eCO.
根系分泌物是植物对逆境环境响应的最直接表现，也是根系与根际间物质交换、能量传递和信息交流的重要媒介。然而，在高 CO 浓度（eCO）下植物根系和分泌物如何响应铝（Al）胁迫尚不清楚。蓖麻是一种世界著名的油料作物，对受金属污染的土壤具有很强的耐受性。在本研究中，基于代谢组学研究了铝胁迫和 eCO 下该物种的根系生理变化和分泌物。结果表明，高浓度 Al 胁迫显著增加了 Al、MDA、脯氨酸和可溶性糖含量，降低了干重和可溶性蛋白浓度。此外，eCO 通过增加干重、抗氧化酶活性和降低 MDA 含量，缓解了高 Al 胁迫对根系生长的抑制。总的来说，在蓖麻分泌物中检测到 511 种代谢物，其中脂质、有机酸和有机含氧化合物分别占 40.82%、17.78%和 12.54%。与对照相比，高 Al 胁迫、eCO 和两者相互作用下，蓖麻的根系分泌物分别有 83、15 和 100 种差异代谢物。与单独 Al 胁迫相比，在 eCO 和 Al 胁迫下发现有 12 种差异代谢物。在 Al 胁迫下，三羧酸（TCA）循环、有机酸和脂质代谢受到抑制；香豆素和碳水化合物缀合物显著上调，这可能有助于蓖麻适应铝污染条件。此外，eCO 增加了有机酸、脂肪酸和碳水化合物的分泌，增强了 Al 胁迫下蓖麻的抗氧化能力和根系生长；eCO 增强了 TCA 循环、有机酸积累、脂质代谢、氨基酸生物合成、戊糖和葡萄糖醛酸相互转化，抑制了 Al 胁迫下蓖麻根系的 DNA 氧化应激。本研究为根系分泌物在 eCO 下提高蓖麻耐铝性方面的重要作用提供了新的见解。
