Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland.
Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
J Chem Ecol. 2022 Oct;48(9-10):730-745. doi: 10.1007/s10886-022-01378-y. Epub 2022 Aug 19.
Plants produce a diversity of secondary metabolites including volatile organic compounds. Some species show discrete variation in these volatile compounds such that individuals within a population can be grouped into distinct chemotypes. A few studies reported that volatile-mediated induced resistance is more effective between plants belonging to the same chemotype and that chemotypes are heritable. The authors concluded that the ability of plants to differentially respond to cues from related individuals that share the same chemotype is a form of kin recognition. These studies assumed plants were actively responding but did not test the mechanism of resistance. A similar result was possible through the passive adsorption and reemission of repellent or toxic VOCs by plants exposed to damage-induced plant volatiles (DIPVs). Here we conducted exposure experiments with five chemotypes of sagebrush in growth chambers; undamaged receiver plants were exposed to either filtered air or DIPVs from mechanically wounded branches. Receiver plants exposed to DIPVs experienced less herbivore damage, which was correlated with increased expression of genes involved in plant defense as well as increased emission of repellent VOCs. Plants belonging to two of the five chemotypes exhibited stronger resistance when exposed to DIPVs from plants of the same chemotypes compared to when DIPVs were from plants of a different chemotype. Moreover, some plants passively absorbed DIPVs and reemitted them, potentially conferring associational resistance. These findings support previous work demonstrating that sagebrush plants actively responded to alarm cues and that the strength of their response was dependent on the chemotypes of the plants involved. This study provides further support for kin recognition in plants but also identified volatile-mediated associational resistance as a passively acquired additional defense mechanism in sagebrush.
植物产生多种次生代谢物，包括挥发性有机化合物。有些物种在这些挥发性化合物中表现出离散的变化，以至于种群中的个体可以分为不同的化学型。有几项研究报告称，挥发性介导的诱导抗性在属于同一化学型的植物之间更为有效，并且化学型是可遗传的。作者得出结论，植物能够对来自具有相同化学型的相关个体的线索做出不同的反应，这是一种亲缘识别的形式。这些研究假设植物是在积极响应，但没有测试抗性的机制。通过暴露于损伤诱导的植物挥发物（DIPV）的植物被动吸附和再释放驱虫或有毒 VOC，也可能产生类似的结果。在这里，我们在生长室中用五种迷迭香化学型进行了暴露实验；未受损的接收植物暴露于过滤空气或机械损伤枝条的 DIPV。暴露于 DIPV 的接收植物受到的食草动物侵害较少，这与参与植物防御的基因表达增加以及驱虫 VOC 排放增加有关。与暴露于不同化学型植物的 DIPV 相比，当暴露于来自相同化学型植物的 DIPV 时，五种化学型中的两种化学型的植物表现出更强的抗性。此外，一些植物被动吸收 DIPV 并重新释放它们，可能赋予关联抗性。这些发现支持了先前的工作，表明迷迭香植物对警报线索积极作出反应，其反应的强度取决于涉及的植物的化学型。这项研究为植物中的亲缘识别提供了进一步的支持，但也确定了挥发性介导的关联抗性是迷迭香植物被动获得的另一种防御机制。
