The Function Of Vesicle Transport Related Gene SlNPSN11 In Tomato Resistance To Powdery Mildew Fungus

Tomato powdery mildew is a parasitic fungal disease,which has been seriously spread and affected tomato yield.Breeding and planting resistant varieties are the most economical,effective strategies against the disease.Studying the function of disease-related genes in tomato can provide theoretical basis for the breeding and improvement of resistant varieties.SNAREs is an important functional protein in plants,which mainly involved in the membrane fusion process in vesicle transportation,there have been no reports on SNAREs protein in tomato resistance to powdery mildew.In this study,Oidium neolycopersici was inoculated on resistant tomato varieties LA1777 and susceptible varieties Money Maker(MM),screening for genes resistant to powdery mildew in the SNAREs family by RT-qPCR.Then,preliminary functional studies of the screened gene were performed by bioinformatics analysis,virus-mediated gene silencing,tobacco transient expression,and subcellular localization,and so on.The results are as follows:1.RT-qPCR analysis of tomato SNAREs family gene expression show that,SlNPSN11 gene expression in disease-resistant varieties was significantly increased compared with susceptible varieties.The SlNPSN11 gene was up-regulated at 6 h after inoculation,and reached the highest level at 12 h,the expression level of SlNPSN11 in resistant varieties was4.8 times that of susceptible varieties at 12 h.Therefore,it is preliminarily predicted that the SlNPSN11 gene may be against O.neolycopersici in tomato.2.Bioinformatics analysis of SlNPSN11 gene showed that,the full length c DNA of SlNPSN11 is 1524 bp,which encodes 261 amino acids,has a transmembrane structure at214-234 bp,and has a Qb-SNARE domain at 142-204 bp.The homology of SlNPSN11 with other species NPSN proteins reached 77.09%,which is the closest relationship with the evolution of potato St NPSN11.Subcellular localization prediction of SlNPSN11 by Prot Comp showed that the SlNPSN11 protein is mainly located in the plasma membrane.1.VIGS results show that,the silenced SlNPSN11 gene plant showed a certain degree of susceptibility after inoculation,the disease severity was 3,3,and 5 at 7 d,14 d,and 21 d after inoculation.The histological observation showed that the production rate of reactive oxygen species and the incidence of HR in the silenced plants were lower than those in the control.In addition,the expression levels of PR1,PR3,and PR5 were significantly decreased in the silenced plants.Therefore,it was determined that SlNPSN11 plays an important role in resistant to powdery mildew.2.The transient expression of SlNPSN11 gene in tobacco showed that,there was no cell necrosis at the sites of injected with PVX,Buffer or PVX-SlNPSN11.However,after injection of BAX at the site of injected with PVX,Buffer or PVX-SlNPSN11,the cell necrosis was obvious.Therefore,the SlNPSNl11 gene in tomato resistance to powdery mildew may not work by producing allergic necrosis.3.The results of subcellular localization indicate that,SlNPSN11 is mainly localized in the plasma membrane and the prediction results in subcellular localization are consistent with bioinformatics.