Centre for Ecology and Conservation, Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, TR10 9EZ, Penryn, UK.
Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK.
J Chem Ecol. 2015 Oct;41(10):956-64. doi: 10.1007/s10886-015-0634-2. Epub 2015 Sep 28.
In some plant-insect interactions, specialist herbivores exploit the chemical defenses of their food plant to their own advantage. Brassica plants produce glucosinolates that are broken down into defensive toxins when tissue is damaged, but the specialist aphid, Brevicoryne brassicae, uses these chemicals against its own natural enemies by becoming a "walking mustard-oil bomb". Analysis of glucosinolate concentrations in plant tissue and associated aphid colonies reveals that not only do aphids sequester glucosinolates, but they do so selectively. Aphids specifically accumulate sinigrin to high concentrations while preferentially excreting a structurally similar glucosinolate, progoitrin. Surveys of aphid infestation in wild populations of Brassica oleracea show that this pattern of sequestration and excretion maps onto host plant use. The probability of aphid infestation decreases with increasing concentrations of progoitrin in plants. Brassica brassicae, therefore, appear to select among food plants according to plant secondary metabolite profiles, and selectively store only some compounds that are used against their own enemies. The results demonstrate chemical and behavioral mechanisms that help to explain evidence of geographic patterns and evolutionary dynamics in Brassica-aphid interactions.
在一些植物-昆虫相互作用中，专门的食草动物会利用它们食物植物的化学防御来为自己谋利。十字花科植物会产生硫代葡萄糖苷，当组织受到损伤时，这些物质会被分解成防御性毒素，但专门的蚜虫，甘蓝蚜，会通过变成“行走的芥子油炸弹”来利用这些化学物质来对抗自己的天敌。对植物组织和相关蚜虫群体中硫代葡萄糖苷浓度的分析表明，蚜虫不仅会隔离硫代葡萄糖苷，而且还会有选择地隔离。蚜虫特别将黑芥子硫苷酸钾积累到高浓度，同时优先排泄结构相似的硫代葡萄糖苷，吲哚-3-乙酰基硫代葡萄糖苷。对野生甘蓝型油菜种群中蚜虫侵染的调查表明，这种隔离和排泄模式与宿主植物的利用有关。随着植物中吲哚-3-乙酰基硫代葡萄糖苷浓度的增加，蚜虫侵染的可能性会降低。因此，甘蓝蚜似乎会根据植物次生代谢产物的特征来选择食物植物，并选择性地只储存一些用于对抗自身天敌的化合物。研究结果证明了有助于解释地理模式和进化动态的化学和行为机制在十字花科-蚜虫相互作用中的证据。
