Conconi A, Smerdon M J, Howe G A, Ryan C A
Institute of Biological Chemistry, Washington State University, Pullman 99164, USA.
Nature. 1996 Oct 31;383(6603):826-9. doi: 10.1038/383826a0.
Many plant genes that respond to environmental and developmental changes are regulated by jasmonic acid, which is derived from linolenic acid via the octadecanoid pathway. Linolenic acid is an important fatty-acid constituent of membranes in most plant species and its intracellular levels increase in response to certain signals. Here we report that irradiation of tomato leaves with ultraviolet light induces the expression of several plant defensive genes that are normally activated through the octadecanoid pathway after wounding. The response to ultraviolet light is blocked by an inhibitor of the octadecanoid pathway and it does not occur in a tomato mutant defective in this pathway. The ultraviolet irradiation maximally induces the defence genes at levels where cyclobutane pyrimidine dimer formation, an indicator of DNA damage, is less than 0.2 dimers per gene. Our evidence indicates that this plant defence response to certain wavelengths of ultraviolet radiation requires the activation of the octadecanoid defence signalling pathway.
许多响应环境和发育变化的植物基因受茉莉酸调控，茉莉酸是通过十八碳酸途径由亚麻酸衍生而来。亚麻酸是大多数植物物种膜的重要脂肪酸成分，其细胞内水平会响应某些信号而增加。我们在此报告，用紫外线照射番茄叶片会诱导几种植物防御基因的表达，这些基因在受伤后通常通过十八碳酸途径被激活。对紫外线的响应被十八碳酸途径的抑制剂阻断，并且在该途径有缺陷的番茄突变体中不会发生。紫外线照射在环丁烷嘧啶二聚体形成（DNA损伤的一个指标）低于每个基因0.2个二聚体的水平下最大程度地诱导防御基因。我们的证据表明，这种植物对特定波长紫外线辐射的防御反应需要激活十八碳酸防御信号通路。
