Data from: Plants and tortoises: mutations in the Arabidopsis jasmonate pathway increase feeding in a vertebrate folivore

Photosynthetic tissues, the major food source of many invertebrates and vertebrates, are well defended. Many defence traits in leaves are controlled via the jasmonate signalling pathway in which jasmonate acts as a hormone by binding to a receptor to activate responses that lead to increased resistance to invertebrate folivores. We predicted that mutations in jasmonate synthesis might also increase the vulnerability of leaves to vertebrate folivores and tested this hypothesis using the Eastern Hermann’s tortoise (Eurotestudo boettgeri) and an Arabidopsis thaliana (Brassicaceae) allene oxide synthase (aos) mutant unable to synthesize jasmonate. Tortoises preferred the aos mutant over the wild type (WT). Based on these results, we then investigated the effect of mutating jasmonate perception using a segregating population of the recessive A. thaliana jasmonate receptor mutant coronatine insensitive1-1 (coi1-1). Genotyping of these plants after tortoise feeding revealed that the homozygous coi1-1 receptor mutant was consumed more readily than the heterozygous mutant or the WT. Therefore, the plant’s ability to synthesize or perceive jasmonate reduces feeding by a vertebrate herbivore. We also tested whether or not tortoise feeding behaviour was influenced by glucosinolates, the principal defence chemicals in Arabidopsis leaves with known roles in defence against many generalist insects. However, in contrast to what has been observed with such insects, leaves in which the levels of these compounds were reduced genetically were consumed at a similar rate to those of the WT.

光合组织是众多无脊椎动物与脊椎动物的主要食物来源，自身具备完善的防御体系。叶片的诸多防御性状均通过茉莉酸（jasmonate）信号通路调控：该通路中茉莉酸作为激素，通过结合受体激活防御反应，进而增强对无脊椎动物食叶者的抗性。我们据此推测，茉莉酸合成相关基因突变或许也会提升叶片对脊椎动物食叶者的易感性，并以此为假说开展实验。实验选用东部赫尔曼陆龟（Eurotestudo boettgeri）以及无法合成茉莉酸的拟南芥（Arabidopsis thaliana，十字花科Brassicaceae）丙二烯氧化物合酶（allene oxide synthase，aos）突变体进行验证。结果显示陆龟更偏好取食aos突变体而非野生型（wild type，WT）植株。基于上述结果，我们进一步利用隐性拟南芥茉莉酸受体突变体coronatine insensitive1-1（coi1-1）的分离群体，探究茉莉酸感知功能受损的突变效应。陆龟取食后对植株进行基因分型的结果显示，纯合coi1-1受体突变体的取食率显著高于杂合突变体与野生型植株。由此可见，植株合成或感知茉莉酸的能力可降低脊椎动物植食者的取食行为。我们同时检测了芥子油苷（glucosinolates）是否会影响陆龟的取食行为——芥子油苷是拟南芥叶片中的主要防御化学物质，已知其在抵御多种广食性昆虫的过程中发挥关键功能。但与针对上述昆虫的研究结果不同，经遗传操作降低此类化合物含量的叶片，其取食率与野生型叶片并无显著差异。