Role of terpene synthases in the defense of Medicago truncatula against Aphanomyces euteiches

植物作为固着生物体与多种生物体相互作用，包括病原体如卵菌纲Aphanomyceseuteiches，其导致豆科植物的根腐病。蒺藜苜蓿根与苜蓿游动孢子的早期接触。euteiches导致编码萜烯脱氢酶（TPS）的基因的表达增强。其中，MtTPS 10被鉴定为在根中特异性表达的多产物倍半萜合酶，并且仅在与卵菌游动孢子接触时表达。MtTPS 10产物，如主要产物喜玛拉醇，有助于M. truncatula根至A.但在植物体中被修饰。第一个候选细胞色素P450酶（CYP-A）转化喜玛拉雅已经确定。此外，对不同生态型的M.结果表明，MtTPS 10表达水平与对白叶枯病的抗性之间通常存在相关性。euteiches一个例外是品系368，它对A. Euteiche但完全缺乏MtTPS 10表达。转录组分析揭示了一个以前未表征的萜烯合酶（MtTPS-X）的表达线368。在该项目的更新中，将检验以下假设：（i）MtTPS-X有助于M.蒺藜品系368;（ii）MtTPS 10和MtTPS-X的转基因表达增加马铃薯植物对致病疫霉的抗性;和（iii）CYP-A在植物中转化MtTPS 10产物。计划在功能上证明368线中的MtTPS-X在防御A.通过转基因方法获得优特奇。此外，MtTPS 10和MtTPS-X将在马铃薯植物中组成型表达，随后测试它们对致病疫霉的抗性。此外，CYP-A在植物中喜玛拉醇转化中的功能将通过突变体植物的表征来分析。这些研究预计将大大提高我们的理解的作用，TPS及其产品在根防御反应，并将是重要的，不仅为潜在的控制卵菌诱导的根病，但卵菌诱导的植物病害的控制一般。

Plants as sessile organisms interact with a variety of organisms, including pathogens such as the oomycete Aphanomyces euteiches, which causes root rot in legumes. The early contact of Medicago truncatula roots with zoospores of A. euteiches leads to an enhanced expression of genes encoding terpene synthases (TPSs). Among them, MtTPS10 was identified as a multi-product sesquiterpene synthase specifically expressed in roots and only upon contact with zoospores of oomycetes. MtTPS10 products, such as the major product himachalol, contribute to the resistance of M. truncatula roots to A. euteiches but are modified in planta. First candidate cytochrome P450 enzyme (CYP-A) converting himachalol has been identified. Furthermore, analysis of different ecotypes of M. truncatula showed that there is often a correlation between MtTPS10 expression levels and resistance to A. euteiches. One exception is line 368, which is highly resistant to A. euteiches but completely lacks MtTPS10 expression. Transcriptome profiling revealed the expression of a previously uncharacterized terpene synthase (MtTPS-X) in line 368. In the renewal of the project the following hypotheses will be tested: (i) MtTPS-X contributes to the immunity of M. truncatula line 368; (ii) transgenic expression of MtTPS10 and MtTPS-X increases resistance of potato plants to Phytophthora infestans; and (iii) CYP-A converts MtTPS10 products in planta. It is planned to functionally proof the role of MtTPS-X in line 368 in defense against A. euteiches by transgenic approaches. Furthermore, MtTPS10 and MtTPS-X will be constitutively expressed in potato plants followed by testing their resistance to P. infestans. In addition, the function of CYP-A in the conversion of himachalol in planta will be analyzed by characterization of mutant plants. These studies are expected to greatly enhance our understanding of the role of TPSs and their products in root defense responses and will be important not only for potential control of oomycete-induced root diseases, but for control of oomycete-induced plant diseases in general.