Different Lepidopteran Elicitors Account for Cross-Talk in Herbivory-Induced Phytohormone Signaling
Different Lepidopteran Elicitors Account for Cross-Talk in Herbivory-Induced Phytohormone Signaling
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DOI：
10.1104/pp.109.139550
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发表时间：
2009-07-01
期刊：
影响因子：
7.4
通讯作者：
Baldwin, Ian T.
中科院分区：
文献类型：
--
作者：
Diezel, Celia;von Dahl, Caroline C.;Baldwin, Ian T.
水杨酸（SA）、茉莉酸（JA）和乙烯（ET）及其互作介导植物对病原菌和植食性昆虫攻击的反应。JA-SA和JA-ET交叉信号已被广泛研究，但对植物-食草动物相互作用中的SA-ET交叉信号知之甚少。当专业植食性烟草天蛾（天蛾）攻击烟草衰减，快速和短暂的JA和ET的爆发，而不显着改变伤口诱导的SA水平。与此相反，攻击从多面手甜菜夜蛾（Spodoptera exigua）的结果在相对较低的JA和ET爆发，但放大SA爆发。这些植物激素的反应是模仿时，物种的幼虫的口腔分泌物（OSSe和OSMs）被添加到穿刺伤口。脂肪酸-氨基酸结合物引起JA和ET爆发，但不引起SA爆发。OSSe具有增强的葡萄糖氧化酶活性（但不具有β-葡萄糖苷酶活性），这足以引起SA爆发并减弱JA和ET水平。已知SA拮抗JA;葡萄糖氧化酶活性和相关的过氧化氢也拮抗ET爆发。我们研究了OSMs诱导的SA爆发在植物中的能力受损，引起JA（反义[as]-lox 3）和ET（反向重复[ir]-aco）爆发和感知ET（35 s-etr 1b）后脂肪酸-氨基酸缀合物的诱导，这表明ET和JA爆发拮抗SA爆发。用乙烯利和1-甲基环丙烷处理野生型植物证实了这些结果，并证明了ET爆发在抑制OSM引起的SA爆发中的核心作用。通过抑制SA爆发，ET爆发可能促进不受约束的JA介导的防御激活，以响应食草动物，否则会引发SA。
Salicylic acid (SA), jasmonic acid (JA), ethylene (ET), and their interactions mediate plant responses to pathogen and herbivore attack. JA-SA and JA-ET cross-signaling are well studied, but little is known about SA-ET cross-signaling in plant-herbivore interactions. When the specialist herbivore tobacco hornworm (Manduca sexta) attacks Nicotiana attenuata, rapid and transient JA and ET bursts are elicited without significantly altering wound-induced SA levels. In contrast, attack from the generalist beet armyworm (Spodoptera exigua) results in comparatively lower JA and ET bursts, but amplified SA bursts. These phytohormone responses are mimicked when the species' larval oral secretions (OSSe and OSMs) are added to puncture wounds. Fatty acid-amino acid conjugates elicit the JA and ET bursts, but not the SA burst. OSSe had enhanced glucose oxidase activity (but not beta-glucosidase activity), which was sufficient to elicit the SA burst and attenuate the JA and ET levels. It is known that SA antagonizes JA; glucose oxidase activity and associated hydrogen peroxide also antagonizes the ET burst. We examined the OSMs-elicited SA burst in plants impaired in their ability to elicit JA (antisense [as]-lox3) and ET (inverted repeat [ir]-aco) bursts and perceive ET (35s-etr1b) after fatty acid-amino acid conjugate elicitation, which revealed that both ET and JA bursts antagonize the SA burst. Treating wild-type plants with ethephone and 1-methylcyclopropane confirmed these results and demonstrated the central role of the ET burst in suppressing the OSMs-elicited SA burst. By suppressing the SA burst, the ET burst likely facilitates unfettered JA-mediated defense activation in response to herbivores that otherwise would elicit SA.