State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
J Chem Ecol. 2013 May;39(5):612-9. doi: 10.1007/s10886-013-0283-2. Epub 2013 Apr 19.
Phloem-feeding whiteflies in the species complex Bemisia tabaci cause extensive crop damage worldwide. One of the reasons for their "success" is their ability to suppress the effectual jasmonic acid (JA) defenses of the host plant. However, little is understood about the mechanisms underlying whitefly suppression of JA-regulated defenses. Here, we showed that the expression of salicylic acid (SA)-responsive genes (EDS1 and PR1) in Arabidopsis thaliana was significantly enhanced during feeding by whitefly nymphs. Whereas upstream JA-responsive genes (LOX2 and OPR3) also were induced, the downstream JA-responsive gene (VSP1) was repressed, i.e., whiteflies only suppressed downstream JA signaling. Gene-expression analyses with various Arabidopsis mutants, including NahG, npr-1, ein2-1, and dde2-2, revealed that SA signaling plays a key role in the suppression of downstream JA defenses by whitefly feeding. Assays confirmed that SA activation enhanced whitefly performance by suppressing downstream JA defenses.
粉虱取食在种复合体中的烟粉虱会对全世界的作物造成广泛的损害。它们之所以“成功”，其中一个原因是它们能够抑制寄主植物中有效的茉莉酸 (JA) 防御。然而，人们对粉虱抑制 JA 调控防御的机制知之甚少。在这里，我们发现，在烟粉虱若虫取食过程中，拟南芥中水杨酸 (SA) 响应基因 (EDS1 和 PR1) 的表达显著增强。而上游的 JA 响应基因 (LOX2 和 OPR3) 也被诱导，下游的 JA 响应基因 (VSP1) 则被抑制，也就是说，粉虱只抑制下游的 JA 信号。用包括 NahG、npr-1、ein2-1 和 dde2-2 在内的各种拟南芥突变体进行的基因表达分析表明，SA 信号转导在粉虱取食过程中抑制下游 JA 防御中起着关键作用。实验证实，SA 的激活通过抑制下游的 JA 防御来增强粉虱的性能。
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