On the initiation of jasmonate biosynthesis in wounded leaves

第一作者：Athen N Kimberlin

第一单位：密苏里大学

通讯作者：Abraham J Koo

 Abstarct 

背景+问题：The basal level of the plant defense hormone jasmonate (JA) in unstressed leaves is low, but wounding causes its near instantaneous increase. How JA biosynthesis is initiated is uncertain, but the lipolysis step that generates fatty acid precursors is generally considered to be the first step. 

在无胁迫的叶片中，植物防御激素茉莉酸盐（JA）的基础水平较低，但创伤会导致JA水平的瞬时增加。JA的生物合成是如何起始的尚不确定，但生成脂肪酸前体的脂解通常被认为是JA生物合成的第一步。

主要研究：Here, we used a series of physiological, pharmacological, genetic, and kinetic analyses of gene expression and hormone profiling to demonstrate that the early spiking of JA upon wounding does not depend on the expression of JA biosynthetic genes in Arabidopsis (Arabidopsis thaliana). 

本文中，作者通过对拟南芥的一系列生理学、药理学、遗传学以及基因表达和激素图谱的动力学分析，揭示了创伤后JA的早期峰值并不依赖于JA生物合成基因的表达。

结果1：Using a transgenic system, we showed how decoupling the responses to wounding and JA prevents the perpetual synthesis of JA in wounded leaves. 

作者通过转基因系统，发现可以通过将创伤和JA响应解耦联，从而防止受伤叶片中JA的永久合成。

结果2：We then used DEFECTIVE IN ANTHER DEHISCENCE1 (DAD1) as a model wound-responsive lipase to demonstrate that although its transient expression in leaves can elicit JA biosynthesis to a low level, an additional level of activation is triggered by wounding, which causes massive accumulation of JA. 

接着，作者利用DAD1作为一个模式创伤响应脂肪酶，表明尽管其在叶片中的瞬时表达能够诱导低水平的JA生物合成，但创伤会诱导额外水平的激活，从而导致了JA的大量积累。

结果3：This wound-triggered boosting effect of DAD1-mediated JA synthesis can happen directly in damaged leaves or indirectly in undamaged remote leaves by the systemically transmitted wound signal. 

这种由创伤刺激的DAD1介导的JA合成能在受伤叶片上直接发生，也可以通过系统性创伤信号传输而间接发生在未受伤的远端叶片上。

结果4：Finally, protein stability of DAD1 was influenced by wounding, α-linolenic acid, and mutation in its catalytic site. 

最后，DAD1的蛋白质稳定性受到创伤、α-亚麻酸及其催化位点突变的影响。

结论：Together, the data support mechanisms that are independent of gene transcription and translation to initiate the rapid JA burst in wounded leaves and demonstrate how transient expression of the lipase can be used to reveal changes occurring at the level of activity and stability of the key lipolytic step.

总之，本文的研究结果揭示了一个独立于基因转录和翻译来启动受伤叶片中快速JA爆发的分子机制，并展示了如何通过对脂肪酶的瞬时表达来揭示在关键脂解步骤的活性和稳定性水平上发生的变化。

** Abraham J. Koo **

doi: https://doi.org/10.1093/plphys/kiac163

Journal: Plant Physiology

 Published date: April 11, 2022