苯丙氨酸裂氨酶在抗禾谷孢囊线虫中的作用及分子调控网络解析

Cereal cyst nematode (CCN) is a widely distributed group of plant nematodes. CCN are obligate sedentary endoparasites and cause severe yield loss on several cereal crops, such as wheat and barley. However, genetic resource of resistance gene to CCN is scarce and the mechanism of resistance is largely unknown in wheat. Previous study of transcriptome of CCN infected Ae. variabilis accession No.1 showed that phenylpropanoid biosynthesis pathway was crucial for plant resistance responses to CCN infection. Phenylalanine ammonia-lyase (PAL) is the first key enzyme of phenylpropanoid biosynthesis pathway and its expression was obviously induced by CCN infection. Using Ae. variabilis-CCN as study model, this project aim to clone the PAL genes and analyze the biological function of PAL in resistance to CCN by BSMV-mediated virus induced gene silencing (VIGS) of PAL. To ravel out the intersection between PAL and plant hormones in resistance response to CCN, Yeast two-Hybrid and Bimolecular Fluorescence Complementation (BIFC) assay will be used to analyze the interaction between PAL and the signaling regulators of plant hormones. Moreover, treatment with plant hormones or analogues will be operated to analyze the roles of plant hormones in CCN resistance response and the signaling network of plant resistance to CCN will be further explored preliminarily. Overall, the interacting roles of plant hormones and PAL in resistance response to CCN infection will be elucidated in this project, which is benefit for unravelling the molecular mechanism of CCN resistance and will provide theoretical knowledge for molecular breeding of wheat resistant to CCN.

禾谷孢囊线虫（Cereal cyst nematode, CCN）分布广，是小麦、大麦等禾谷类作物的重要地下害虫之一。然而，已分离的小麦有效抗CCN的基因很少且分子机制研究尚浅。课题组通过分析易变山羊草1号CCN侵染后转录组，发现苯丙烷代谢途径在整个抗性应答中具有重要作用，其关键酶苯丙氨酸裂氨酶（Phenylalanine ammonia-lyase, PAL）的表达受到了强烈诱导。本课题拟以易变山羊草-CCN作为研究系统，克隆PAL基因，通过BSMV介导的基因沉默技术评价PAL在抗CCN反应中的作用；通过酵母双杂交和双荧光分子互补实验，分析PAL与植物激素信号调控因子间的互作；通过激素或类似物处理，分析激素在抗CCN反应中的作用并揭示PAL与之在抗性中的关联，初步解析PAL在抗CCN反应中的信号网络；为进一步研究抗CCN分子机制与小麦抗CCN品种的培育提供理论依据和基础。

禾谷孢囊线虫（Cereal cyst nematode, CCN）分布广，是小麦、大麦等禾谷类作物的重要地下害虫之一。然而，已分离的小麦有效抗CCN的基因很少且分子机制研究尚浅。本项目以易变山羊草-CCN作为研究系统，克隆了易变山羊草1号的苯丙氨酸解氨酶PAL1（AeVPAL1）基因的全长编码序列，验证了AeVPAL1的表达受CCN 侵染诱导，显著上调；通过BSMV介导的基因沉默技术明确了PAL在抗CCN反应中的正向调控作用；通过分析AeVPAL1对植物激素的影响，发现AeVPAL1对SA、JA的积累有显著影响，但对IAA, CTK等无影响，进一步采用外源激素或类似物处理，发现SA对CCN抗性起作用，但JA并不起作用。双荧光分子互补实验未检测到AeVPAL1与ARR、KFB之间的互作。此外，在研究过程中发现，PAL与TDC之间存在相关性，在基因表达、对SA含量的影响以及下游代谢产物含量等方面都体现出了一致性。此外，我们已获得AeVPAL1转基因小麦纯系，并对其CCN抗性进行了初步验证，结果表明AeVPAL1转基因小麦对CCN的抗性明显强于对照植株。研究结果表明AeVPAL1基因可作为抗CCN育种的基因资源加以应用。