Thaler Jennifer S, Karban Richard, Ullman Diane E, Boege Karina, Bostock Richard M
Department of Botany, University of Toronto, 25 Willcocks St., Toronto, M5 S 3B2, Canada.
Department of Entomology, University of California, Davis, CA, 95616, USA.
Oecologia. 2002 Apr;131(2):227-235. doi: 10.1007/s00442-002-0885-9. Epub 2002 Apr 1.
Plants are often attacked by many herbivorous insects and pathogens at the same time. Two important suites of responses to attack are mediated by plant hormones, jasmonate and salicylate, which independently provide resistance to herbivorous insects and pathogens, respectively. Several lines of evidence suggest that there is negative cross-talk between the jasmonate and salicylate response pathways. This biochemical link between general plant defense strategies means that deploying defenses against one attacker can positively or negatively affect other attackers. In this study, we tested for cross-talk in the jasmonate and salicylate signaling pathways in a wild tomato and examined the effects of cross-talk on an array of herbivores of cultivated tomato plants. In the wild cultivar, induction of defenses signaled by salicylate reduced biochemical expression of the jasmonate pathway but did not influence performance of S. exigua caterpillars. This indicates that the signal interaction is not a result of agricultural selection. In cultivated tomato, biochemical attenuation of the activity of a defense protein (polyphenol oxidase) in dual-elicited plants resulted in increased of performance of cabbage looper caterpillars, but not thrips, spider mites, hornworm caterpillars or the bacteria Pseudomonas syringae pv. tomato. In addition, we tested the effects of jasmonate-induced resistance on the ability of thrips to vector tomato spotted wilt virus. Although thrips fed less on induced plants, this did not affect the level of disease. Thus, the negative interaction between jasmonate and salicylate signaling had biological consequences for two lepidopteran larvae but not for several other herbivores tested or on the spread of a disease.
植物常常会同时受到多种食草昆虫和病原体的攻击。植物对攻击的两种重要反应途径由植物激素茉莉酸和水杨酸介导，它们分别独立地为植物提供对食草昆虫和病原体的抗性。多项证据表明，茉莉酸和水杨酸反应途径之间存在负向相互作用。植物一般防御策略之间的这种生化联系意味着，针对一种攻击者部署防御措施可能会对其他攻击者产生正向或负向影响。在本研究中，我们测试了野生番茄中茉莉酸和水杨酸信号通路之间的相互作用，并研究了这种相互作用对栽培番茄植株上一系列食草动物的影响。在野生品种中，由水杨酸介导的防御诱导降低了茉莉酸途径的生化表达，但不影响甜菜夜蛾幼虫的生长。这表明这种信号相互作用不是农业选择的结果。在栽培番茄中，双重诱导植株中一种防御蛋白（多酚氧化酶）活性的生化减弱导致小菜蛾幼虫的生长增加，但对蓟马、叶螨、烟草天蛾幼虫或番茄丁香假单胞菌番茄致病变种没有影响。此外，我们测试了茉莉酸诱导的抗性对蓟马传播番茄斑萎病毒能力的影响。虽然取食诱导植株的蓟马较少，但这并不影响病害水平。因此，茉莉酸和水杨酸信号之间的负向相互作用对两种鳞翅目幼虫产生了生物学影响，但对测试的其他几种食草动物或病害传播没有影响。
