Glutathionylation and reduction of methacrolein in tomato plants account for its absorption from the vapor phase
Glutathionylation and reduction of methacrolein in tomato plants account for its absorption from the vapor phase
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番茄植株中的谷胱甘肽化和甲基丙烯醛的还原是其从气相吸收的原因
DOI：
10.1104/pp.15.01045
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发表时间：
2015
期刊：
影响因子：
7.4
通讯作者：
K. Matsui
中科院分区：
文献类型：
--
作者：
S. Muramoto;Y. Matsubara;CM. Mwenda;T. Koeduka;T. Sakami;A. Tani;K. Matsui
植物释放的挥发性有机化合物有很大一部分被氧化生成反应性羰基，对大气化学有很大影响。植物吸收活性羰基物质驱动的植被沉积在净化大气中起着重要作用，但支持这种吸收的机制很少得到研究。在这里，我们用异戊二烯形成的主要活性羰基之一甲基丙烯醛（MACR）和番茄（Solanum lycopersicum）植物进行了模型实验。将番茄芽置于含有MACR蒸气的罐子中，有效地吸收了MACR。从MACR的气液分配系数来看，MACR的吸收效率远高于预期，表明MACR可能在叶片组织中被代谢。在经MACR蒸汽处理的番茄组织顶空和内部检测到异丁醛、异丁醇和甲基醇（MAA），表明MACR被酶还原。同时检测谷胱甘肽（GSH）的MACR （MACR-GSH）和MAA （MAA-GSH）缀合物。MACR-GSH本质上是由内源性GSH和外源性MACR自发结合形成的，MACR-GSH还原为MAA-GSH可能是由番茄叶片中nadph依赖酶催化的。谷胱甘肽化是吸收MACR最主要的代谢途径，但当MACR的量超过可利用谷胱甘肽时，MACR积累的光合能力降低。在利用气流模拟自然环境的实验中，MACR- gsh和MAA-GSH积累占供给量的30% ~ 40%。这些结果表明，MACR代谢，特别是自发谷胱甘肽化，是支持番茄植株从大气中吸收MACR的重要因素。
A large portion of the volatile organic compounds emitted by plants are oxygenated to yield reactive carbonyl species, which have a big impact on atmospheric chemistry. Deposition to vegetation driven by the absorption of reactive carbonyl species into plants plays a major role in cleansing the atmosphere, but the mechanisms supporting this absorption have been little examined. Here, we performed model experiments using methacrolein (MACR), one of the major reactive carbonyl species formed from isoprene, and tomato (Solanum lycopersicum) plants. Tomato shoots enclosed in a jar with MACR vapor efficiently absorbed MACR. The absorption efficiency was much higher than expected from the gas/liquid partition coefficient of MACR, indicating that MACR was likely metabolized in leaf tissues. Isobutyraldehyde, isobutyl alcohol, and methallyl alcohol (MAA) were detected in the headspace and inside tomato tissues treated with MACR vapor, suggesting that MACR was enzymatically reduced. Glutathione (GSH) conjugates of MACR (MACR-GSH) and MAA (MAA-GSH) were also detected. MACR-GSH was essentially formed through spontaneous conjugation between endogenous GSH and exogenous MACR, and reduction of MACR-GSH to MAA-GSH was likely catalyzed by an NADPH-dependent enzyme in tomato leaves. Glutathionylation was the metabolic pathway most responsible for the absorption of MACR, but when the amount of MACR exceeded the available GSH, MACR that accumulated reduced photosynthetic capacity. In an experiment simulating the natural environment using gas flow, MACR-GSH and MAA-GSH accumulation accounted for 30% to 40% of the MACR supplied. These results suggest that MACR metabolism, especially spontaneous glutathionylation, is an essential factor supporting MACR absorption from the atmosphere by tomato plants.