α-SNAP及其介导的膜泡运输在大豆与大豆孢囊线虫互作中的机制研究

Soybean cyst nematode (SCN, Heterodera glycines) is one of the most damaging pathogen of soybean. The use of SCN-resistant cultivars is the most effective means of managing SCN population levels in the field. Rhg1 is widely used in SCN breeding program. Previous studies revealed that copy number variation that elevates the expression of three genes at Rhg1 confers SCN resistance. As a critical component of vesicle trafficking, α-SNAP (alpha soluble NSF [N-ethylmaleimide-sensitive factor] attachment protein) plays an important role in Rhg1-mediated SCN resistance. But little is known about the mechanism by which these α-SNAPs contribute to resitance. In this project, we’ll dissect the molecular basis of α-SNAPs in SCN resistance. Our studies revealed that α-SNAP interacted with SAP5 and SAP6, and the expression of α-SNAP is upregulated in nematode-infected tissue. We’re going to identify the functions of α-SNAPs through the analysis of α-SNAP-interactive proteins. The upsteam components that regulate the expression of α-SNAPs will be identified. And the role of vesicle trafficking in the feeding cell formation will also be investigated. Overall, our studies will help us understand the molecular mechanism underlying the functions of α-SNAP during plant-nematode interaction, providing us a potential means to engineer crop resistance to the nematode.

大豆孢囊线虫病是影响大豆生产的最具毁灭性的病害之一，利用抗病品种是最有效的绿色防控措施之一。大豆抗孢囊线虫关键位点Rhg1在抗病育种中的应用最广泛。前期的研究表明，Rhg1拷贝数目增加导致该位点内三个基因表达量的升高，从而提高大豆抗病性。作为膜泡运输的重要成员，α-SNAP是Rhg1位点中的关键基因，但其抗病分子机制还不是很清楚。本项目将在前期工作的基础上深入研究α-SNAP抗病的分子机制。初步的实验结果表明，α-SNAP与SAK5和SAK6两个蛋白互作，α-SNAP基因的表达量在侵染位点受到调控。我们将进一步研究α-SNAP与SAK5和SAK6的互作机制，解析α-SNAP基因受诱导表达的分子机制，揭示α-SNAP介导的膜泡运输在取食细胞形成中的功能。项目旨在阐明α-SNAP的抗病机制和调控网络，扩展我们对植物与寄生线虫互作机制的认识，为作物抗病育种提供重要的理论依据。

大豆孢囊囊线虫是影响大豆产量和品质提高的重要因素。大豆孢囊线虫抗性主效位点Rhg1表现为广谱高抗，本项目对Rhg1位点上的α-SNAP的互作蛋白进行分离鉴定，发现α-SNAP及其介导的膜泡运输通过调控细胞死亡影响大豆孢囊线虫抗性。我们发现SNARE复合体组分GmSYP31A诱导细胞死亡，α-SNAP通过与GmSYP31A以及电压依赖型阴离子通道GmVDAC1D互作，影响蛋白分泌途径和线粒体介导的细胞死亡，进而调控孢囊线虫抗性。利用转录组分析鉴定到的线虫诱导型启动子启动α-SNAP的特异性表达，可以显著增强大豆对线虫的抗性。另外对α-SNAP的另一个互作蛋白GmYKT61A的功能研究发现，R-SNARE参与孢囊线虫抗性且不同亚家族功能不同。我们的研究发现了膜泡运输复合体在Rhg1介导的孢囊线虫抗性中的重要功能，为深入解析植物线虫互作分子机制提供了理论依据。