Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, SLU, Uppsala SE-75007, Sweden.
Plant Physiol Biochem. 2012 Jan;50(1):72-8. doi: 10.1016/j.plaphy.2011.07.014. Epub 2011 Jul 29.
Upon herbivory glucosinolates are known to be degraded into a cascade of secondary products that can be detrimental for certain herbivores. We performed herbivory bioassays using first and second instar generalist Lepidoptera larvae Spodoptera littoralis on Arabidopsis thaliana engineered to overexpress novel glucosinolates. A differential response in larval feeding patterns was observed on the plants engineered with novel glucosinolates. Larvae fed on plants overexpressing 4-hydroxybenzyl glucosinolate and isopropyl glucosinolate showed little response. Larvae fed on 35S:CYP79A2 plants engineered to overexpress benzyl glucosinolates, however, showed reduced larval and pupal weights. Upon herbivory a high expression of JA signalling gene LOX2 was observed on the 35S:CYP79A2 plants compared to the PR1a and VSP2 expression. To confirm the role of benzyl isothiocyanate (BITC), a degradation product of benzyl glucosinolate overexpressing plants, in the retarded larval growth we used Virus Induced Gene Silencing (VIGS) approach to silence LOX2 expression in the 35S:CYP79A2 plants. S. littoralis larvae fed on LOX2 silenced 35S:CYP79A2 plants exhibited a retarded larval growth thus indicating that BITC played a pivotal role in anti-herbivory and not only the JA signalling pathway.
当植物受到食草动物侵害时，硫代葡萄糖苷会被降解为一系列次生代谢产物，这些产物可能对某些食草动物有害。我们使用第一和第二龄期的通用鳞翅目幼虫斜纹夜蛾（Spodoptera littoralis）对拟南芥进行了食草生物测定，这些拟南芥经过基因工程改造，过度表达了新型硫代葡萄糖苷。在过度表达新型硫代葡萄糖苷的植物上，观察到幼虫取食模式的差异反应。喂食 4-羟基苄基硫代葡萄糖苷和异丙基硫代葡萄糖苷的幼虫几乎没有反应。然而，喂食过度表达苄基硫代葡萄糖苷的 35S:CYP79A2 植物的幼虫和蛹体重减轻。在受到食草动物侵害后，与 PR1a 和 VSP2 的表达相比，在 35S:CYP79A2 植物上观察到 JA 信号基因 LOX2 的高表达。为了确认苄基异硫氰酸酯（BITC），即过度表达苄基硫代葡萄糖苷植物的降解产物，在幼虫生长迟缓中的作用，我们使用病毒诱导基因沉默（VIGS）方法沉默 35S:CYP79A2 植物中的 LOX2 表达。喂食 LOX2 沉默的 35S:CYP79A2 植物的斜纹夜蛾幼虫表现出生长迟缓，这表明 BITC 在抗食草性中起关键作用，而不仅仅是 JA 信号通路。
