Identification of the OsOPR7 gene encoding 12-oxophytodienoate reductase involved in the biosynthesis of jasmonic acid in rice
Identification of the OsOPR7 gene encoding 12-oxophytodienoate reductase involved in the biosynthesis of jasmonic acid in rice
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DOI：
10.1007/s00425-007-0635-7
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发表时间：
2008-02
期刊：
影响因子：
4.3
通讯作者：
T. Tani;H. Sobajima;K. Okada;Tetsuya Chujo;S. Arimura;N. Tsutsumi;M. Nishimura;H. Seto;H. Nojiri-H.
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文献类型：
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作者：
T. Tani;H. Sobajima;K. Okada;Tetsuya Chujo;S. Arimura;N. Tsutsumi;M. Nishimura;H. Seto;H. Nojiri-H.
12-氧二烯酸（OPDA）还原酶（EC1.3.1.42）参与茉莉酸（JA）的生物合成，催化OPDA的10,11 -双键还原生成3-氧-2-（2′-戊烯基）-环戊烷-1-辛酸（OPC-8:0）。水稻osopr1基因编码的OPDA还原酶（OPR）优先转化(−)-顺式OPDA，而不是(+)-顺式OPDA，这是JA的天然前体。在这里，我们提供证据表明水稻8号染色体上的OPR家族基因dosopr7编码参与JA生物合成的酶。重组OsOPR7-His蛋白有效催化了顺式opda的两个对映体的还原，类似于拟南芥（L.）中的OPR3蛋白。Heynh。osopr7mrna在机械损伤和干旱胁迫后0.5 h内表达量达到最大值，内源JA水平随着inosopr7mrna表达量的增加而开始升高。GFP-OsOPR7融合蛋白仅在洋葱表皮细胞过氧化物酶体中检测到。此外，利用拟南芥opr3突变体进行的互补分析表明，oopr7基因能够弥补由JA缺乏引起的突变体的雄性不育表型，而tosopr1基因则不能，并且通过表达oopr7基因，oopr3突变体的JA产量也得以恢复。我们得出结论，osopr7基因编码催化水稻JA生物合成天然(+)-顺式opda还原的酶。
Enzyme 12-oxophytodienoate (OPDA) reductase (EC1.3.1.42), which is involved in the biosynthesis of jasmonic acid (JA), catalyses the reduction of 10, 11-double bonds of OPDA to yield 3-oxo-2-(2′-pentenyl)-cyclopentane-1-octanoic acid (OPC-8:0). The riceOsOPR1gene encodes OPDA reductase (OPR) converting (−)-cis-OPDA preferentially, rather than (+)-cis-OPDA, a natural precursor of JA. Here, we provide evidence that an OPR family gene in rice chromosome 8, designatedOsOPR7, encodes the enzyme involved in the JA biosynthesis. Recombinant OsOPR7-His protein efficiently catalysed the reduction of both enantiomers ofcis-OPDA, similar to the OPR3 protein inArabidopsisthaliana(L.) Heynh. The expression ofOsOPR7mRNA was induced and reached maximum levels within 0.5 h of mechanical wounding and drought stress, and the endogenous JA level started to increase in accordance with the increase inOsOPR7expression. The GFP-OsOPR7 fusion protein was detected exclusively in peroxisomes in onion epidermal cells. Furthermore, complementation analysis using anArabidopsisopr3mutant indicated that theOsOPR7gene, but notOsOPR1, was able to complement the phenotypes of male sterility in the mutant caused by JA deficiency, and that JA production in theopr3mutant was also restored by the expression of theOsOPR7gene. We conclude that theOsOPR7gene encodes the enzyme catalysing the reduction of natural (+)-cis-OPDA for the JA biosynthesis in rice.