Wounding caused by insects or abiotic factors such as wind and hail can cause severe stress for plants. Intrigued by the observation that wounding induces expression of genes involved in surface wax synthesis in a jasmonoyl-isoleucine (JA-Ile)-independent manner, the role of wax biosynthesis and respective genes upon wounding was investigated. Wax, a lipid-based barrier, protects plants both from environmental threats as well as from an uncontrolled loss of water. Its biosynthesis is described to be regulated by abscisic acid (ABA), whereas the main wound-signal is the hormone JA-Ile. We show in this study, that genes coding for enzymes of surface wax synthesis are induced upon wounding in Arabidopsis thaliana leaves in a JA-Ile-independent but ABA-dependent manner. Furthermore, the ABA-dependent transcription factor MYB96 is a key regulator of wax biosynthesis upon wounding. On the metabolite level, wound-induced wax accumulation is strongly reduced in JA-Ile-deficient plants, but this induction is only slightly decreased in ABA-reduced plants. To further analyze the ABA-dependent wound response, we conducted wounding experiments in high humidity. They show that high humidity prevents the wound-induced wax accumulation in A. thaliana leaves. Together the data presented in this study show that wound-induced wax accumulation is JA-Ile-dependent on the metabolite level, but the expression of genes coding for enzymes of wax synthesis is regulated by ABA.

中文翻译：

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受伤以脱落酸和茉莉酰异亮氨酸依赖性方式触发拟南芥叶子中的蜡生物合成

昆虫或非生物因素（例如风和冰雹）造成的伤害会给植物带来严重的压力。伤口以不依赖茉莉酰异亮氨酸（JA-Ile）的方式诱导参与表面蜡合成的基因表达，这一观察引起了人们的兴趣，研究了蜡生物合成和相应基因在伤口中的作用。蜡是一种基于脂质的屏障，可以保护植物免受环境威胁以及不受控制的水分流失。据描述，其生物合成受脱落酸 (ABA) 调节，而主要的伤口信号是激素 JA-Ile。我们在这项研究中表明，编码表面蜡合成酶的基因在拟南芥叶子受伤时以不依赖 JA-Ile 但依赖 ABA 的方式被诱导。此外，ABA 依赖性转录因子 MYB96 是伤口时蜡生物合成的关键调节因子。在代谢物水平上，在 JA-Ile 缺陷的植物中，伤口诱导的蜡积累强烈减少，但在 ABA 减少的植物中，这种诱导仅略有减少。为了进一步分析 ABA 依赖性伤口反应，我们在高湿度下进行了伤口实验。他们表明，高湿度可以防止拟南芥叶子中伤口引起的蜡积累。本研究中提供的数据共同表明，伤口诱导的蜡积累是 JA-Ile 依赖于代谢物水平的，但编码蜡合成酶的基因的表达受 ABA 调节。