Genetic Transformation Of GST-L3 Gene In Tomato And The Expression Analysis Of ARF Genes In Tomato Bacterial Wilt Disease

Tomato bacterial wilt caused by Ralstonia solanacearum is one of the main diseases in tomato production. This disease is destructive during the hot and humid rainy seasons in Southern China. Due to the limited effectiveness of chemical and biological control, breeding disease-resistant varieties is becoming the most effective way for preventing against this disease. The research on the mechanism of disease resistance will facilitate the planning of disease-resistant breeding strategies.The current research consists of two parts. Firstly, the GST-L3 gene which has been preciously proved to be related to the bacterial wilt resistance in tomato was transferred into a susceptible tomato ‘M82’ through Agrobacterium-mediated transgenic method to verify the gene function. Secondly, differential expression of tomato auxin response factor(ARF) in resistant and susceptible tomatoes when challenged with Ralstonia solanacearum was anlysesed using a semi-quantitative technology.The main results were as follows:1.For in vitro tomato regeneration. The best differentiation medium was MS+ 6-BA 1.0mg/L+IAA0.8mg/L. The best root-inducing medium was MS+IAA0.5 mg/L. The best genetic transformation condition of tomato was to pre-culture for 2 d and co-culture for 2 d with the kanamycin concentration of 50 mg/L.2.GST-L3 gene was successfully transferred into suscepatible tomato ‘M82’ using the Agrobacterium-mediated transgenic method. When inoculated with Ralstonia solanacearum, the transgenic plants showed a delay on the onset of wilting symptoms compared with wild type ‘M82’, indicating that GST-L3 was related to the resistance to bacterial wilt in tomato.3.Exogenous application of IAA enhanced the wilt symptoms on resistant and susceptible tomatoes, indicating a negative role of IAA in plant disease resistance reaction. 22 auxin response factors(ARF) were identified from tomato genome through bioinformatic method. Their differential expression in root, stem and leaf of resistant and susceptible tomatoes after challenged with Ralstonia solanacearum was anlysesed using a semi-quantitative technology.