Screening For MiRNA Of Tobacco Resistance To Potato Virus Y And And Function Analysis Of Relevant MiRNA

Tobacco is an important economic crop in China, potato virus Y (PVY) is one of the most important diseases in tobacco production. In recent years, the outbreak of PVY in main tobacco production areas in our country tends to be aggravated year by year.On the current production for PVY effective and there is no agent, therefore, cultivating PVY resistance of tobacco varieties is the most effective way for prevention of the disease.However, understanding the molecular mechanism of the interaction between virus and tobacco is the key to solve this problem.Recent studies showed that microRNA(miRNA) plays an important role in regulating plant resistance to virus infection. Our research explore the effect of PVY infectionon the expression of endogenous miRNA, to understand whether regulating the expression of endogenous miRNA genes has antiviral function in tobacco.ethereby provides a new insight for tobacco virus prevention a and disease resistant breeding..The main research results of this research are as follows:1. Small RNA were sequencd for both PVY infection samples and healthy controls., The results showed that PVY infection can change the expression level of endogenous miRNA. PVY infection can significantly affect the 81 tobacco endogenous miRNA expression changes, which 57,miRNA were upregulated and 21 were downreaulated., to target genes of the changed miRNAs were also analysis further..2. The nta-miR156g, nta-miR396b, nta-miR169a, nta-miR6149a which were upreaulated after PVY infection, nta-miR6019a which was downregulated after PVY infection and nta-miR168a, nta-miR172c which were not changed after PVY infection were selected for Northern Blot analysis, results showed that the hybridization results were consistent with the results of sequencing and variance analysis.3. Tobacco nta-miR396b was chosen for further functional analysis. The plant overexpression vector of nta-miR396b was constructed then introduced into A. tumefaciens strain EHA105. Transformation of tobacco cultivars K326 was performed using the leaf disc method. Transgenic plants were allowed to grow for 2 generations for further studies.4. Resistance identification of the T2 generation of transgenic and the control to PVY infection were analysis.The results showed that the onset of transgenic tobacco delay, less transgenic tobacco symptoms abate, confirmed that the tobacco nta-miR396b has the function to PVY resistance infection.This research,provided new ways for the prevention of PVY in the respect of miRNAs, Our results proved that the tobacco endogenous miRNA has the anti-virus function.providing a new thought for the research of plant virus.