Identification and Symbiotic Phenotype Characterization of an OPDA Reductase Gene AsOPR1 in Chinese Milk Vetch
Identification and Symbiotic Phenotype Characterization of an OPDA Reductase Gene AsOPR1 in Chinese Milk Vetch
复制标题
紫云英OPDA还原酶基因AsOPR1的鉴定及共生表型特征
DOI：
10.1007/s11105-017-1038-y
复制
发表时间：
2017
影响因子：
2.1
通讯作者：
Li Youguo
中科院分区：
文献类型：
--
作者：
Wei Feng;Lei Lei;Chen Fangfang;Wu Mei;Chen Dasong;Li Youguo
在高等植物中，12-氧代植物二烯酸还原酶(OPR)家族主要由两个亚类组成。类OPR3酶属于亚组II，是茉莉酸(JA)生物合成的关键功能酶，而亚组I类OPR1酶的功能仍不清楚，尤其是在共生中。本研究鉴定了中华黄芪中一个编码12-氧植物二烯酸还原酶的基因，并对其功能进行了研究。序列同源性分析表明，该基因编码一个类似OPR1的酶。结果表明，接种华中根瘤菌7653R后，AsOPR1基因表达上调。亚细胞定位结果表明，在未感染的寄主细胞中，AsOPR1定位于叶绿体的分化形式--淀粉体中，而在感染细胞中AsOPR1与根瘤菌共定位。AsOPR1基因的敲除使转基因根的根瘤数减少到对照的34.6%，显著降低了转基因根和根瘤中的JA水平，而AsOPR1基因的过表达导致根瘤分生组织变大，但对根瘤数没有影响。综上所述，这些结果表明AsOPR1可能参与了根瘤形成和发育的调控，并影响了内源JA的代谢。
In higher plants, the 12-oxo-phytodienoic acid reductase (OPR) family mainly consists of two subgroups. OPR3-like enzymes belong to subgroup II, and they were proved to be key functional enzymes participating in jasmonic acid (JA) biosynthesis, while functions of OPR1-like enzymes classified into subgroup I remain largely unclear, particularly in symbiosis. This study identified and functionally characterized a gene encoding 12-oxophytodienoate reductase in Astragalus sinicus. Sequence homology analysis indicated that this gene encodes an OPR1-like enzyme. It was found that the gene expression of AsOPR1 was upregulated after inoculation with Mesorhizobium huakuii 7653R. Subcellular localization showed that in uninfected host plant cells, AsOPR1 was localized in the amyloplast, a differentiated form of plastid; while in the infected cells, AsOPR1 co-localized with rhizobia. Knockdown of the AsOPR1 gene decreased the nodule number to 34.6% that of the control roots, and significantly reduced the JA level in both transgenic roots and nodules, while overexpression of the AsOPR1 gene resulted in enlarged nodule meristem, but caused no changes in nodule number. Taken together, these results indicate that AsOPR1 may participate in the regulation of nodule formation and development, as well as affect endogenous JA metabolism.