Blechert S, Brodschelm W, Hölder S, Kammerer L, Kutchan T M, Mueller M J, Xia Z Q, Zenk M H
Lehrstuhl für Pharmazeutische Biologie, Universität München, Germany.
Proc Natl Acad Sci U S A. 1995 May 9;92(10):4099-105. doi: 10.1073/pnas.92.10.4099.
Plant defense against microbial pathogens and herbivores relies heavily on the induction of defense proteins and low molecular weight antibiotics. The signals between perception of the aggression, gene activation, and the subsequent biosynthesis of secondary compounds are assumed to be pentacylic oxylipin derivatives. The rapid, but transient, synthesis of cis-jasmonic acid was demonstrated after insect attack on a food plant and by microbial elicitor addition to plant suspension cultures. This effect is highly specific and not caused by a number of environmental stresses such as light, heavy metals, or cold or heat shock. Elicitation of Eschscholtzia cell cultures also led to a rapid alkalinization of the growth medium prior to jasmonate formation. Inhibition of this alkalinization process by the protein kinase inhibitor staurosporine also inhibited jasmonate formation. The induction of specific enzymes in the benzo[c]phenanthridine alkaloid pathway leading to the antimicrobial sanguinarine was induced to a qualitatively and quantitatively similar extent by fungal elicitor, methyl jasmonate, and its linolenic acid-derived precursor 12-oxophytodienoic acid. It is herein proposed that a second oxylipid cascade may exist in plants starting from linoleic acid via 15,16-dihydro-12-oxophytodienoic acid to 9,10-dihydrojasmonate. Experiments with synthetic trihomojasmonate demonstrated that beta-oxidation is not a prerequisite for biological activity and that 12-oxophytodienoic acid and derivatives are most likely fully active as signal transducers. Octadecanoic acid-derived compounds are essential elements in modulating the synthesis of antibiotic compounds and are thus integral to plant defense.
植物抵御微生物病原体和食草动物的侵害在很大程度上依赖于防御蛋白和低分子量抗生素的诱导。在感受到侵害、基因激活以及随后次生化合物的生物合成之间的信号，被认为是五环氧化脂质衍生物。在昆虫攻击食用植物后以及向植物悬浮培养物中添加微生物激发子后，已证明会快速但短暂地合成顺式茉莉酸。这种效应具有高度特异性，并非由多种环境胁迫如光照、重金属、冷或热激引起。对花菱草细胞培养物的激发还导致在茉莉酸形成之前生长培养基迅速碱化。蛋白激酶抑制剂星形孢菌素对这种碱化过程的抑制也抑制了茉莉酸的形成。真菌激发子、茉莉酸甲酯及其亚麻酸衍生的前体12-氧代植物二烯酸在导致抗菌血根碱的苯并[c]菲啶生物碱途径中诱导特定酶的程度在定性和定量上相似。本文提出，植物中可能存在第二条氧化脂质级联反应，从亚油酸开始，经15,16-二氢-12-氧代植物二烯酸到9,10-二氢茉莉酸。合成三高茉莉酸的实验表明，β-氧化不是生物活性的先决条件，并且12-氧代植物二烯酸及其衍生物很可能作为信号转导分子具有完全活性。源自十八烷酸的化合物是调节抗生素化合物合成的必需元素，因此是植物防御不可或缺的一部分。
