An OPR3-independent pathway uses 4,5-didehydrojasmonate for jasmonate synthesis
An OPR3-independent pathway uses 4,5-didehydrojasmonate for jasmonate synthesis
复制标题
DOI：
10.1038/nchembio.2540
复制
发表时间：
2018-02-01
影响因子：
14.8
通讯作者：
Solano, Roberto
中科院分区：
文献类型：
--
作者：
Chini, Andrea;Monte, Isabel;Solano, Roberto
植物激素茉莉酰基-异亮氨酸（JA-Ile）的生物合成需要通过OPDA还原酶3（OPR 3）还原JA前体12-氧代-植物二烯酸（OPDA）。先前对opr 3 -1拟南芥突变体的分析表明OPDA信号传导作用独立于JA-Ile及其受体COI 1;然而，这一假设受到挑战，因为opr 3 -1是条件等位基因，在JA-Ile生物合成中未完全受损。为了阐明OPR 3和OPDA在JA非依赖性防御中的作用，我们分离并表征了功能丧失的opr 3 -3等位基因。引人注目的是，opr 3 -3植物仍然对坏死营养型病原体和昆虫取食具有抗性，并激活COI 1依赖的JA介导的基因表达。OPDA衍生物的分析鉴定了受伤的野生型和opr 3 -3植物中的4，5-二脱氢-JA。发现OPR 2将4，5-二脱氢-JA还原为JA，解释了opr 3 -3突变体中JA-Ile的积累和JA-Ile应答的激活。我们的研究结果表明，在OPR 3的情况下，OPDA进入β-氧化途径，产生4，5-ddh-JA作为JA和JA-Ile的直接前体，从而确定了JA生物合成的OPR 3非依赖性途径。
Biosynthesis of the phytohormone jasmonoyl-isoleucine (JA-Ile) requires reduction of the JA precursor 12-oxo-phytodienoic acid (OPDA) by OPDA reductase 3 (OPR3). Previous analyses of the opr3-1 Arabidopsis mutant suggested an OPDA signaling role independent of JA-Ile and its receptor COI1; however, this hypothesis has been challenged because opr3-1 is a conditional allele not completely impaired in JA-Ile biosynthesis. To clarify the role of OPR3 and OPDA in JA-independent defenses, we isolated and characterized a loss-of-function opr3-3 allele. Strikingly, opr3-3 plants remained resistant to necrotrophic pathogens and insect feeding, and activated COI1-dependent JA-mediated gene expression. Analysis of OPDA derivatives identified 4,5-didehydro-JA in wounded wild-type and opr3-3 plants. OPR2 was found to reduce 4,5-didehydro-JA to JA, explaining the accumulation of JA-Ile and activation of JA-Ile-responses in opr3-3 mutants. Our results demonstrate that in the absence of OPR3, OPDA enters the beta-oxidation pathway to produce 4,5-ddh-JA as a direct precursor of JA and JA-Ile, thus identifying an OPR3-independent pathway for JA biosynthesis.