Role of lupeol synthase in Lotus japonicus nodule formation
Role of lupeol synthase in Lotus japonicus nodule formation
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DOI：
10.1111/j.1469-8137.2010.03463.x
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发表时间：
2011-01-01
期刊：
影响因子：
9.4
通讯作者：
Papadopoulou, Kalliope K.
中科院分区：
文献类型：
--
作者：
Delis, Costas;Krokida, Afrodite;Papadopoulou, Kalliope K.
三萜是植物次生代谢产物，由氧化角鲨烯环化酶（OSC）催化氧化角鲨烯环化而成。在这里，我们研究了羽扇豆醇合成酶，编码的OSC 3，其产品，羽扇豆醇，在发展中的模式豆科植物百脉根和根瘤的作用。OSC 3的表达模式在不同发育阶段的未感染的根和根感染中慢生根瘤菌loti。原位杂交分析OSC 3表达的组织特异性。功能分析表明，转基因L.产生对OSC 3沉默的根。通过GC-MS确定在沉默的植物系中不存在羽扇豆醇。在OSC 3沉默的植物系中，结节原基起始的标记基因ENOD 40的表达显著增加，表明羽扇豆醇影响结节形成。沉默的植物也表现出更快的再生表型，与此一致。外源羽扇豆醇对M.感染loti的野生型植物进一步证明了羽扇豆醇对ENOD 40表达的负调控作用。根和结节可以单独归因于OSC 3。综上所述，我们的数据表明羽扇豆醇生物合成的作用，通过调节ENOD 40基因的表达，在结节形成。
P>Triterpenes are plant secondary metabolites, derived from the cyclization of 2,3-oxidosqualene by oxidosqualene cyclases (OSCs). Here, we investigated the role of lupeol synthase, encoded by OSC3, and its product, lupeol, in developing roots and nodules of the model legume Lotus japonicus.The expression patterns of OSC3 in different developmental stages of uninfected roots and in roots infected with Mesorhizobium loti were determined. The tissue specificity of OSC3 expression was analysed by in situ hybridization. Functional analysis, in which transgenic L. japonicus roots silenced for OSC3 were generated, was performed. The absence of lupeol in the silenced plant lines was determined by GC-MS.The expression of ENOD40, a marker gene for nodule primordia initiation, was increased significantly in the OSC3-silenced plant lines, suggesting that lupeol influences nodule formation. Silenced plants also showed a more rapid nodulation phenotype, consistent with this. Exogenous application of lupeol to M. loti-infected wild-type plants provided further evidence for a negative regulatory effect of lupeol on the expression of ENOD40.The synthesis of lupeol in L. japonicus roots and nodules can be solely attributed to OSC3. Taken together, our data suggest a role for lupeol biosynthesis in nodule formation through the regulation of ENOD40 gene expression.