Identification of a Hexenal Reductase That Modulates the Composition of Green Leaf Volatiles
Identification of a Hexenal Reductase That Modulates the Composition of Green Leaf Volatiles
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DOI：
10.1104/pp.18.00632
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发表时间：
2018-10-01
期刊：
影响因子：
7.4
通讯作者：
Matsui, Kenji
中科院分区：
文献类型：
--
作者：
Tanaka, Toshiyuki;Ikeda, Ayana;Matsui, Kenji
绿色叶挥发物（GLV）包括六碳（C6）醛、醇和酯，其是植物组织受损时形成的。GLV在伤口部位的直接植物防御，通过吸引食草动物捕食者的间接植物防御以及植物-植物通信中发挥作用。GLV组分在其目标受体中引起独特的反应;因此，GLV组成的控制对于植物适当地管理胁迫反应是重要的。将C6-醛还原成C6-醇是控制GLV组成的关键步骤，并且对于避免C6-醛的毒性积累也是重要的。然而，C6-醛还原背后的分子机制仍然知之甚少。在这项研究中，我们纯化了拟南芥（拟南芥）NADPH依赖的肉桂醛和己烯醛还原酶At 4g 37980编码，命名为肉桂醛和己烯醛还原酶（CINNAMALDEHYDE AND HEXENAL REDUCTASE（CINNAMALDEHYDE AND HEXENAL REDUCTASE））。C6 T-DNA敲除突变体植物表现出正常的生长表型，然而，我们观察到C6-酒精生产的显着抑制后，部分机械创伤或草食动物侵扰。我们的数据还表明，寄生蜂Cotesia vestalis是更吸引GLVs从草食动物出没的野生型植物相比，GLVs从CHR植物，这对应于减少C6-酒精水平的突变体中发出。此外，chr植物更容易受到外源高剂量暴露于（Z）-3-己烯醛，表明其显着降低的光系统II活性。我们的研究表明，还原酶在改变GLV组成中起着重要作用，因此，在避免挥发性羰基化合物的毒性和吸引食草动物捕食者方面很重要。
Green leaf volatiles (GLVs), including six-carbon (C6) aldehydes, alcohols, and esters, are formed when plant tissues are damaged. GLVs play roles in direct plant defense at wound sites, indirect plant defense via the attraction of herbivore predators, and plant-plant communication. GLV components provoke distinctive responses in their target recipients; therefore, the control of GLV composition is important for plants to appropriately manage stress responses. The reduction of C6-aldehydes into C6-alcohols is a key step in the control of GLV composition and also is important to avoid a toxic buildup of C6-aldehydes. However, the molecular mechanisms behind C6-aldehyde reduction remain poorly understood. In this study, we purified an Arabidopsis (Arabidopsis thaliana) NADPH-dependent cinnamaldehyde and hexenal reductase encoded by At4g37980, named here CINNAMALDEHYDE AND HEXENAL REDUCTASE (CHR). CHR T-DNA knockout mutant plants displayed a normal growth phenotype; however, we observed significant suppression of C6-alcohol production following partial mechanical wounding or herbivore infestation. Our data also showed that the parasitic wasp Cotesia vestalis was more attracted to GLVs emitted from herbivore-infested wild-type plants compared with GLVs emitted from chr plants, which corresponded with reduced C6-alcohol levels in the mutant. Moreover, chr plants were more susceptible to exogenous high-dose exposure to (Z)-3-hexenal, as indicated by their markedly lowered photosystem II activity. Our study shows that reductases play significant roles in changing GLV composition and, thus, are important in avoiding toxicity from volatile carbonyls and in the attraction of herbivore predators.