Abstract Phenolic biosynthesis in carrots is increased when subjected to wounding and ultraviolet (UV) light stresses. In this study, the physiological role of reactive oxygen species (ROS), ethylene (ET), and jasmonic acid (JA) as signaling molecules to elicit this stress response was evaluated. ROS (O2− and hydrogen peroxide) were the first signaling molecules produced, then ET, followed by lipoxygenase (LOX) activity, which is a key enzyme in JA biosynthesis. After a sequence of syntheses of these signaling molecules, phenylalanine ammonia-lyase (PAL) was activated and phenolics were accumulated. We followed a chemical biology approach (using chemical inhibitors of stress-signaling pathways) to determine the physiological role of ROS, ET, and JA on the wound and UV (UVA, UVB, and UVC) induced biosynthesis of phenolics. Results indicated that ROS play a major role on the combined UV and wounding stress response. It is proposed that UV induces ROS which acts as a signal for ET biosynthesis, which in turn activates JA biosynthesis following the wound signaling cross-talk model we previously proposed. When both stresses are applied simultaneously, an enhanced effect on the accumulation of phenolics is observed due to higher levels of signaling molecules.

中文翻译：

---

活性氧、乙烯和茉莉酸对紫外线诱导的胡萝卜损伤组织酚类生物合成的生理作用

摘要 当受到伤害和紫外线 (UV) 光胁迫时，胡萝卜中的酚类生物合成会增加。在这项研究中，评估了活性氧 (ROS)、乙烯 (ET) 和茉莉酸 (JA) 作为信号分子引发这种应激反应的生理作用。ROS（O2− 和过氧化氢）是第一个产生的信号分子，然后是 ET，接着是脂氧合酶 (LOX) 活性，这是 JA 生物合成中的关键酶。在合成这些信号分子的序列后，苯丙氨酸解氨酶 (PAL) 被激活并积累酚类物质。我们遵循化学生物学方法（使用应激信号通路的化学抑制剂）来确定 ROS、ET 和 JA 对伤口和紫外线（UVA、UVB 和 UVC）诱导的酚类生物合成的生理作用。结果表明，ROS 对联合紫外线和伤害应激反应起主要作用。有人提出，UV 诱导 ROS 作为 ET 生物合成的信号，继而在我们之前提出的伤口信号串扰模型之后激活 JA 生物合成。当同时施加两种压力时，由于更高水平的信号分子，观察到对酚类物质积累的影响增强。