Molecular Mechanism Of Interference Between Cucumber Mosaic Virus And Tomato Mosaic Virus On Solanum Lycopersicum

Cucumber mosaic virus (CMV) and Tomato mosaic virus (ToMV) are two major plant viruses on tomato (Solanum lycopersicum). ToMV-N5 was isolated from tomato plants in Shanghai in 2005, which induced necrosis on tomato cv. Hezuo 903 and mosaic on tomato cv. Zhongshu 4th. ToMV-N5 was inoculated on tomato plants, which had been infected by CMV-Fny, the necrotic phenotype on tomato cv. Hezuo 903 disappeared, while the mosaic phenotype on tomato cv. Zhongshu 4th became more serious. The results indicated that the two viruses induced synergism on tomato cv. Hezuo 903, while synergism on tomato cv. Zhongshu 4th, and the phenomenon maybe related to the genotypes of Tm2. CMV-Fny and ToMV-N5 were inoculated on tomato species, symptoms induced by the viruses and relationships with the genotype of Tm2 were investigated. Accumulation levels of Tm2 gene and miRNAs in tomato cv. Hezuo 903 which has been inoculated with CMV-Fny and ToMV-N5 separately or complexly were analyzed by real-time quantitative PCR. The research provided basis for molecular mechanism of interaction between CMV-Fny and ToMV-N5 on tomato plants.1. CMV-Fny and ToMV-N5 were inoculated separately or complexly on tomato cv. Hezuo903,the male and female parent of tomato cv. Hezuo 903 and also tomato cv. Money maker. The results showed that the complex infection appeared interference on hybrid strain tomato cv. Hezuo 903, while synergism on tomato cv. Money maker and the male and female parent of tomato cv. Hezuo 903.2. The genotypes of Tm2 gene in tomato cv. Hezuo 903 and the male and female parent of it were determined by cloning and sequencing, and the genotypes were Tm-22/ tm-2,tm-2/ tm-2 and Tm-22/ Tm-22 respectively.3. The accumulation levels of Tm2 gene in tomato cv. Hezuo 903 inoculated with CMV-Fny and ToMV-N5 were analyzed by real-time quantification PCR. The results indicated that the accumulation levels of Tm2 gene in tomato leaves inoculated with CMV-Fny were substantially similar to that of healthy controls, while the accumulation increased in tomato leaves infected by ToMV-N5 or coinfected by ToMV-N5 and CMV-Fny. 4. According to the miRNA microarray results, 10 miRNAs(miR156,miR159,miR160,miR162,miR164,miR165/166,miR167,miR168,miR169 and miR171)associated with morphological development,hormone response and metabolism in tomato were selected for real-time quantitative PCR to analyse the accumulation levels of the 10 miRNAs in tomato leaves after infected by CMV-Fny and ToMV-N5. The results showed higher value of 10 miRNAs after separate and complex infection, especially miRNA162 and miRNA168. The accumulation levels of miRNAs in tomato leaves infected by ToMV-N5 was less abundant than that by complex infection, while the levels were the most in CMV-Fny infecting tomato plants.