Allene oxide synthase (AOS) and hydroperoxide lyase (HPL) are two important members of P450 enzymes metabolizing hydroperoxy fatty acid to produce jasmonates and aldehydes respectively, which function in response to diverse environmental and developmental stimuli. However, their exact roles in soybean have not been clarified. In present study, we identified a lesion‐mimic mutant in soybean named NT302, which exhibits etiolated phenotype together with chlorotic and spontaneous lesions on leaves at R3 podding stage. The underlying gene was identified as GmHPL encoding hydroperoxide lyase by map‐based cloning strategy. Sequence analysis demonstrated that a single nucleotide mutation created a premature termination codon (Gln20‐Ter), which resulted in a truncated GmHPL protein in NT302. GmHPL RNA was significantly reduced in NT302 mutant, while genes in AOS branch of the 13‐LOX pathway were up‐regulated in NT302. The mutant exhibited higher susceptibility to bacterial leaf pustule (BLP) disease, but increased resistance against common cutworm (CCW) pest. GmHPL was significantly induced in response to MeJA, wounding, and CCW in wild type soybean. Virus induced gene silencing (VIGS) of GhHPL genes gave rise to similar lesion‐mimic leaf phenotypes in upland cotton, coupled with upregulation of the expression of JA biosynthesis and JA‐induced genes. Our study provides evidence that competition exist between HPL and AOS branches in 13‐LOX pathway of the oxylipin metabolism in soybean, thereby plays essential roles in modulation of plant development and defense.

中文翻译：

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氢过氧化物裂解酶调节大豆防御反应并赋予模拟病变叶表型 (Glycine max (L.) Merr.)


丙二烯氧化物合酶 (AOS) 和氢过氧化物裂解酶 (HPL) 是 P450 酶的两个重要成员，分别代谢氢过氧脂肪酸产生茉莉酸和醛，其功能是响应不同的环境和发育刺激。然而，它们在大豆中的确切作用尚未明确。在本研究中，我们在大豆中发现了一种名为NT302的模拟病变突变体，该突变体在 R3 结荚期表现出黄化表型以及褪绿和自发病变。通过基于图谱的克隆策略，将潜在基因鉴定为编码氢过氧化物裂解酶的GmHPL 。序列分析表明，单核苷酸突变产生了提前终止密码子 (Gln20-Ter)，从而导致NT302中出现截短的 GmHPL 蛋白。 NT302突变体中GmHPL RNA 显着减少，而 13-LOX 途径 AOS 分支中的基因在NT302中上调。该突变体对细菌性叶脓疱病 (BLP) 病表现出更高的易感性，但对地老虎 (CCW) 害虫的抵抗力增强。在野生型大豆中， GmHPL对 MeJA、创伤和 CCW 的反应显着诱导。 GhHPL基因的病毒诱导基因沉默 (VIGS) 在陆地棉中产生了类似的模拟病变叶表型，同时上调了 JA 生物合成和 JA 诱导基因的表达。我们的研究提供了证据，表明大豆氧脂素代谢的 13-LOX 途径中 HPL 和 AOS 分支之间存在竞争，从而在植物发育和防御的调节中发挥重要作用。