Jasmonates trigger prey-induced formation of 'outer stomach' in carnivorous sundew plants
Jasmonates trigger prey-induced formation of 'outer stomach' in carnivorous sundew plants
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DOI：
10.1098/rspb.2013.0228
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发表时间：
2013-05-22
影响因子：
4.7
通讯作者：
Mithoefer, Axel
中科院分区：
文献类型：
--
作者：
Nakamura, Yoko;Reichelt, Michael;Mithoefer, Axel
生长相关的植物激素生长素是启动植物器官弯曲运动的内源信号，已被广泛接受。1875年，查尔斯·达尔文描述了肉食性太阳露物种树叶的弯曲运动如何形成一个‘外胃’，使植物能够包围并消化捕获的昆虫猎物。大约100年后，生长素被认为是导致这一运动的因素。我们报告说，猎物捕获诱导叶片弯曲和与防御相关的茉莉酸植物激素的积累。在捕食果蝇后3h内，在叶片运动的同时，我们检测到茉莉酸及其异亮氨酸结合物的增加。这种积累在空间上仅限于叶片的弯曲部分。仅使用茉莉酸酯就足以引发叶片弯曲。只有活的果蝇或碾碎的果蝇的体液才会引起叶片弯曲；无论是死果蝇还是机械处理都没有任何效果。我们的发现有力地表明，Drosera‘外胃’的形成是一种化学运动，由内源茉莉酸的积累触发。这些结果表明，在肉食性阳光露水植物中，茉莉酸级联可能被调整为促进肉食，而不是防御草食动物。
It has been widely accepted that the growth-related phytohormone auxin is the endogenous signal that initiates bending movements of plant organs. In 1875, Charles Darwin described how the bending movement of leaves in carnivorous sundew species formed an 'outer stomach' that allowed the plants to enclose and digest captured insect prey. About 100 years later, auxin was suggested to be the factor responsible for this movement. We report that prey capture induces both leaf bending and the accumulation of defence-related jasmonate phytohormones. In Drosera capensis fed with fruitflies, within 3 h after prey capture and simultaneous with leaf movement, we detected an increase in jasmonic acid and its isoleucine conjugate. This accumulation was spatially restricted to the bending segment of the leaves. The application of jasmonates alone was sufficient to trigger leaf bending. Only living fruitflies or the body fluids of crushed fruitflies induced leaf curvature; neither dead flies nor mechanical treatment had any effect. Our findings strongly suggest that the formation of the 'outer stomach' in Drosera is a chemonastic movement that is triggered by accumulation of endogenous jasmonates. These results suggest that in carnivorous sundew plants the jasmonate cascade might have been adapted to facilitate carnivory rather than to defend against herbivores.