马铃薯寄主因子StDnaJ基因参与病毒侵染和调节寄主抗性的机制研究

Viral diseases cause great loss of tuber yield and quality, which is one of the important limiting factors restricting the potato production in China. Viruses are small parasite in host cells that only encode few proteins, they must recruit the host factors and cellular mechanisms to complete the infection cycles. These host factors facilitate the virus infection, translation, replication and transportation process, mutations of some important host factors will result in recessively inherited resistance to plant viruses due to loss of susceptiblity in hosts. therefore insight into the founction of host factor can help us understand the virus infection strategy, and may provide us a novel way that is different with the R gene and RNA silencing pathway for the genetic improvement of potato virus resistance and control of viral diseases. In previous work, a potato host factor StDnaJ gene that was upregulated in the compatible potato-virus interactions was cloned. Expression patterns and bioinformations analysis showed its functions involved in virus cell-to-cell spread in host. Basis on the results, this study further screening the viral proteins and/or other host factors interacted with StDnaJ by using proteomics methods, and release the molecular mechanism and regulatory network of potato StDnaJ involved in the virus infection and transportation. The research results will help us to understand the mechanism of the host factors-virus inteactions, and furthermore propose a new strategy for improvement of potato virus resistance.

病毒病严重影响马铃薯块茎的产量和品质，是制约我国马铃薯生产的重要限制因子。病毒寄生于细胞内，自身仅编码少数蛋白，必须利用寄主的因子和细胞机制才能完成侵染循环，这些重要寄主因子是病毒的侵染、翻译、复制和运输等过程所必需的，一旦它们发生变化，寄主就不再适合病毒寄生而产生抗性，因此对这些寄主因子作用机制的研究不仅可以帮助我们理解病毒的侵染策略，而且可能为马铃薯病毒抗性的遗传改良提出一条区别于R基因和RNA沉默机制的新途径。实验室在前期研究中克隆了一个在马铃薯-病毒亲和互作中上调表达的寄主因子StDnaJ基因，表达模式和生物信息学分析显示该基因可能参与病毒的胞间运输。在此基础上，本研究进一步利用蛋白组学等方法系统筛选参与这一过程的病毒蛋白和其它寄主因子，以揭示StDnaJ协助病毒侵染的作用机制和调控网络。研究结果将有助于揭示马铃薯相关寄主因子与病毒互作的分子机制，并提出改良马铃薯病毒抗性的新策略。

病毒病是制约我国马铃薯生产的重要限制因子，并且严重影响马铃薯块茎的产量和品质。病毒寄生于寄主细胞内，必须利用寄主的因子才能完成侵染循环，这些重要寄主因子是我们理解和调控寄主对病毒抗病性和感病性的关键要素。本研究鉴定了一个新的马铃薯寄主感病因子，并对其参与PVY侵染马铃薯的相关机制进行了揭示。结果显示，在StDnaJ干涉的转基因马铃薯中，PVY的侵染明显被镇压，病毒含量显著低于同时期的野生型对照，而超量表达StDnaJ的转基因马铃薯病毒含量与对照差异不明显。进一步通过酵母双杂系统，鉴定出一个马铃薯蛋白和四个病毒蛋白可能与StDnaJ互作。因此，马铃薯寄主因子StDnaJ与Hsp70共同定位与细胞质和细胞核中，并通过与病毒蛋白P1、HC-Pro、VPg和CP互作，帮助了PVY侵染马铃薯这样过程被初步揭示。这些结果帮助我们进一步增进了对马铃薯寄主因子与病毒互作的机制的理解，同时也证明了通过调控关键寄主感病因子改良马铃薯病毒抗性这一新策略的可行性。