桃蚜取食对抗、感蚜辣椒品种水杨酸、茉莉酸信号途径的影响

为了明确水杨酸及茉莉酸信号途径在辣椒抗蚜性中的重要作用,本研究在获得遗传稳定的抗、感蚜参照辣椒品种的基础上,系统开展了桃蚜为害前后抗、感蚜参照辣椒品种叶组织中水杨酸、茉莉酸含量及相关基因表达量的差异分析。结果表明,桃蚜为害后,水杨酸含量在抗蚜辣椒品种‘猪大肠’（ZDC）和感蚜辣椒品种‘大羊角椒’（DYJJ）中均比为害前显著提高,而茉莉酸含量在ZDC中显著提高,在DYJJ中则先显著降低之后又恢复到为害前水平。水杨酸信号途径相关基因PR1、EDS5、PAD4的表达量在ZDC、DYJJ被桃蚜为害后均能够显著诱导,并且桃蚜为害早期PR1和EDS5基因在ZDC中的表达量显著高于DYJJ。ZDC被桃蚜为害后,茉莉酸信号途径基因LOX2、AOC的表达量比为害前先显著提高,之后又逐渐降低至为害前水平,而这2个基因在DYJJ中的表达被显著抑制,并且也显著低于ZDC中的表达水平。研究结果表明,抗蚜辣椒品种可以同时激活水杨酸、茉莉酸信号途径抵御桃蚜为害,而感蚜辣椒品种激活水杨酸途径、显著抑制茉莉酸途径则有利于桃蚜为害。本研究从以上2个防御信号途径初步揭示了辣椒的抗蚜性分子机理。

Myzus persicae Feeding Effects Salicylic Acid and Jasmonic Acid Signaling Pathways in Aphid-resistant and Aphid-susceptible Pepper Cultivars

In order to clarify the important role of salicylic acid and jasmonic acid signal pathways in pepper aphid resistance, the study was based on obtaining genetically stable resistant and susceptible pepper varieties, and systematically carried out the difference analysis of salicylic acid and jasmonic acid content and related gene expression in leaf tissue of the aphid-resistance and aphid-susceptible reference peppers cultivars before and after damaged by Myzus persicae. After damaged by M. persicae, the content of salicylic acid in the aphid-resistant pepper variety ZDC and the aphid-susceptible pepper variety DYJJ increased significantly, while the content of jasmonic acid increased significantly in ZDC. In DYJJ, it decreased significantly and then returned to the pre-damage level. The expression levels of salicylic acid signaling pathway related genes PR1, EDS5, PAD4 could be significantly induced after ZDC and DYJJ damaged by M. persicae, and the expression level of PR1 and EDS5 genes in ZDC was significantly higher in ZDC and DYJJ in the early stage of damage. After ZDC was damaged by green peach aphid, the expression level of the jasmonic acid signaling pathway genes LOX2 and AOC increased significantly, and then gradually decreased to the pre-damage level. The expression of the genes in DYJJ was significantly inhibited and also significantly lower than that in ZDC. The results of this study indicate that pepper-resistant varieties can simultaneously activate salicylic acid and jasmonic acid signal pathways to resist the damage of green peach aphid, while the aphid-susceptible pepper variety activates the salicylic acid pathway and significantly inhibits the jasmonic acid pathway, which is beneficial to the green peach aphid infestation. This study initially revealed the molecular mechanism of pepper’s aphid resistance from the above two defense signal pathways.