College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, China.
Sci Rep. 2017 Apr 7;7:46185. doi: 10.1038/srep46185.
Although aerobic methane (CH) release from plants leads to an intense scientific and public controversy in the recent years, the potential functions of endogenous CH production in plants are still largely unknown. Here, we reported that polyethylene glycol (PEG)-induced osmotic stress significantly increased CH production and soluble sugar contents in maize (Zea mays L.) root tissues. These enhancements were more pronounced in the drought stress-tolerant cultivar Zhengdan 958 (ZD958) than in the drought stress-sensitive cultivar Zhongjiangyu No.1 (ZJY1). Exogenously applied 0.65 mM CH not only increased endogenous CH production, but also decreased the contents of thiobarbituric acid reactive substances. PEG-induced water deficit symptoms, such as decreased biomass and relative water contents in both root and shoot tissues, were also alleviated. These beneficial responses paralleled the increases in the contents of soluble sugar and the reduced ascorbic acid (AsA), and the ratio of AsA/dehydroascorbate (DHA). Further comparison of transcript profiles of some key enzymes in sugar and AsA metabolism suggested that CH might participate in sugar signaling, which in turn increased AsA production and recycling. Together, these results suggested that CH might function as a gaseous molecule that enhances osmotic stress tolerance in maize by modulating sugar and AsA metabolism.
虽然植物有氧产甲烷（CH）在近年来引起了科学界和公众的激烈争论，但植物内源性 CH 产生的潜在功能在很大程度上仍然未知。在这里，我们报道了聚乙二醇（PEG）诱导的渗透胁迫显著增加了玉米（Zea mays L.）根组织中的 CH 产量和可溶性糖含量。在耐旱品种郑单 958（ZD958）中，这些增强作用比在耐旱敏感品种中江玉 1 号（ZJY1）中更为明显。外源施加 0.65mM CH 不仅增加了内源性 CH 产量，还降低了硫代巴比妥酸反应物质的含量。PEG 诱导的水分亏缺症状，如根和茎叶组织生物量和相对含水量的降低，也得到了缓解。这些有益的反应与可溶性糖含量的增加以及抗坏血酸（AsA）和脱氢抗坏血酸（DHA）的比值的降低平行。对一些糖和 AsA 代谢关键酶的转录谱的进一步比较表明，CH 可能参与糖信号转导，从而增加 AsA 的产生和循环。综上所述，这些结果表明，CH 可能作为一种气态分子，通过调节糖和 AsA 代谢，增强玉米对渗透胁迫的耐受性。
