Altered glucosinolate hydrolysis in genetically engineered Arabidopsis thaliana and its influence on the larval development of Spodoptera littoralis
Altered glucosinolate hydrolysis in genetically engineered Arabidopsis thaliana and its influence on the larval development of Spodoptera littoralis
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DOI：
10.1007/s10886-006-9149-1
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发表时间：
2006-11-01
影响因子：
2.3
通讯作者：
Wittstock, Ute
中科院分区：
文献类型：
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作者：
Burow, Meike;Mueller, Rene;Wittstock, Ute
芥子目植物中发现的芥子油苷-黑芥子酶防御系统的抗草食动物潜力很大程度上受到植物受损时亲本芥子油苷形成的水解产物类型（例如异硫氰酸盐、腈）的影响。然而，由于缺乏合适的严格生物测定实验工具，芥子油苷水解产物对昆虫食草动物的影响的比较受到阻碍，例如完整的植物仅在其产生的水解产物类型上有所不同，或者可以准确模拟芥子油苷水解的人工饲料。拟南芥的广泛分子资源有助于鉴定在芥子油苷水解中发挥作用的几个基因。其中之一编码环硫特异性蛋白（ESP），该蛋白在拟南芥的某些生态型中以异硫氰酸盐为代价促进腈的形成。我们在产生异硫氰酸盐的生态型Columbia-0中过表达来自产生腈的生态型Landsbergecta的ESP cDNA，以产生拟南芥的转基因品系，其在组织损伤时形成的芥子油苷水解产物的类型方面与野生型植物不同，而亲本芥子油苷谱和黑芥子酶活性水平以及植物形态和生长习性保持不变。对典型草食动物斜纹夜蛾（鳞翅目：夜蛾科）进行的生物测定表明，在产生腈的品系上饲养的幼虫在第一个幼虫阶段的平均体重增长速度比以产生异硫氰酸酯的对照植物为食的幼虫要快。此外，在 ESP 过度表达的植物品系中，具有中等生长速率的幼虫表现出较早化蛹的趋势。结合之前的研究结果，这些发现表明异硫氰酸盐比腈更能有效地防御食草昆虫，并提出了植物中腈形成的条件选择的问题。
The antiherbivore potential of the glucosinolate-myrosinase defense system found in plants of the order Capparales is heavily influenced by the types of hydrolysis products (e.g. isothiocyanates, nitriles) formed from the parent glucosinolates upon plant damage. However, comparison of the effects of glucosinolate hydrolysis products on insect herbivores has been hampered by the lack of suitable experimental tools for rigorous bioassays, such as intact plants differing only in the types of hydrolysis products they produce, or artificial diets that can accurately simulate glucosinolate hydrolysis. The wide array of molecular resources for Arabidopsis thaliana has facilitated the identification of several genes that play a role in glucosinolate hydrolysis. One of these encodes the epithio-specifier protein (ESP) that promotes the formation of nitriles at the expense of isothiocyanates in certain ecotypes of A. thaliana. We overexpressed the ESP cDNA from the nitrile-producing ecotype Landsberg erecta in the isothiocyanate-producing ecotype Columbia-0 to generate transgenic lines of A. thaliana that differed from wild-type plants in the type of glucosinolate hydrolysis products formed upon tissue damage, whereas parent glucosinolate profile and myrosinase activity levels, as well as plant morphology and growth habit, remained unchanged. Bioassays with the model generalist herbivore Spodoptera littoralis (Lepidoptera: Noctuidae) demonstrated that larvae reared on the nitrile-producing lines on average gained weight faster in the first larval stages than larvae that fed on isothiocyanate-producing control plants. Furthermore, larvae with medial growth rates showed a tendency to pupate earlier on the ESP-overexpressing plant lines. Together with the results of previous studies, these findings suggest that isothiocyanates are more effective defenses against insect herbivores than nitriles, and raise questions about what conditions select for nitrile formation in plants.