In plants the hormone jasmonic acid (JA) is synthesized in response to attack by pathogens and herbivores, leading to activation of defense responses. Rapidly following JA accumulation the hormone is metabolized, presumably to prevent inhibitive effects of high JA levels on growth and development. The enzymes that directly inactivate JA were so far unknown. Here, we identify four jasmonate-induced oxygenases (JOXs) in
在植物中,激素茉莉酸(JA)会在受到病原体和食草动物攻击时合成,导致防御反应的激活。在JA积累后,该激素快速代谢,可能是为了防止高JA水平对生长和发育的抑制作用。直接失活JA的酶至今尚未被发现。在这里,我们在拟南芥中鉴定了四种茉莉酸诱导的氧化酶(JOXs),它们使茉莉酸羟基化形成无活性的12-OH-JA。不再产生这四种酶的突变体,会高度积累JA,表现出生长减缓,并对对JA依赖性防御敏感的攻击者高度抵抗。因此,JOX酶在平衡生长-防御权衡中起着重要作用,决定JA反应的振幅和持续时间。