Effect Of Receptor-Like Kinase Gene StLRPK1 On Potato Against Phytophthora Infestans

Potato late blight, caused by Phytophthhora infestans, is one of the most devastating diseases of potato wordwide, which causes huge ceconomic losses. A potato receptor-like kinase gene StLRPK1 was cloned before. It was upregulated by P. infestans and overexpression of StLRPK1 in tobacoo could enhance late blight resistance. In this study we further investigated its functions against late blight in potato through the overexpression and RNA interference methods.The main results are as follows:1. Promoter region of StLRPK1 was amplyfied from genomic DNA. In addition to a number of basal promoter structural elements,2338 bp sequence contained sevral cis elements which responseble for pathogen, hormone, abiotic stress as well as some organ specific cis elements. Fusion vector of the promoter and GUS gene was constructed and transformed into Nicotiana tobacum by Agrobacterium. After PCR identification,10 transgenic plants were obtained.2. pFF19-StLRPK1-GFP vectors was constructed and transfomed into epidermal cells of onions by the particle bombardment method. Laser confocal microscopy displayed that pFF19-StLRPK1-GFP mainly located in plasma membrane, while in control, GFP distributed in the whole cells. Which implicated that StLRPK1 exercised it function on plasma membrane.3. Overexpression and RNA interference vectors of StLRPKl were constructed and transformed into potato varietie E3.13 overexpression and 10 RNA interference transgenic lines were obtained. Realtime-PCR analysis showed that the expressionin level were different among the transgenic lines. The higest expression level in overexpression line was 47.8 times than that of control. In interference lines, the interference efficiency was up to 96%.4. The high efficency overexpressed and silenced transgenic lines were selected for futher late blight resistance test. The inoculation results demonstrated that relative lesion growth rate in overexpressed lines was significantly lower than that of control. While the relative lesion growth rate of RNA interference lines was higher than control. These results demonstrated that StLRPK1 as an improtant horizontal resistance candidate gene plays a role in potato late blight resistance.Under 150 mM NaC1 salt stress condition, the growth of overexpression and RNA specific interference transgenic seedings lines were both inhibited, but the latter is more serious than that of former. These results implied that StLRPK1 may participate in the process of salt stress.