Identification Of Tomato Yellow Leaf Curl Disease And Research On The Correlation With The Leaf Structure

Tomato yellow leaf curl virus (TYLCV) is one of the most devastating viruses of cultivated tomato in the world, and it has become the limiting factor on the production of tomato in both field and protected cultivation systems. Recent years,TYLCV has resulted in great economic losses, and it is spreading towards north from south in China. Disease-resistant breeding is the most effective and direct method to deal with the disease up to now. Using 10 resistant and 2 susceptible tomato materials to tomato yellow leaf curl virus, this study detected the TYLCV in tomato; paraffin section and scanning electronic microscope were used to study the correlation between TYLCV and the structure of tomato leaf; identified resistance genes to TYLCV using PCR method, and verified the resistance in the field by nature infection. The contents and results were as follows:1. Based on the conserved regions of the reported nucleotide sequences of Tomato yellow leaf curl virus (TYLCV), a pair of primers was designed to anneal to the conserved sequence. The tomato samples infected TYLCV-like were detected by PCR. A 800bp specific fragment was amplified from the samples. The specific fragment was cloned and sequenced, and the sequence was compared with all nucleotide sequences in GenBank by Blast of NCBI. The result showed that the fragment belonged to tomato yellow leaf curl virus DNA.2. According to the growth of tomato and the prevalence of tomato yellow leaf curl disease, making paraffin section and scanning electronic microscope. The results showed that the resistance to tomato yellow leaf curl virus was not affected by the cell array structure of the leaf , but tomato yellow leaf curl virus had great impact on cell array structure; the resistance to tomato yellow leaf curl virus was affected by the surface structure of the leaf , and tomato yellow leaf curl virus had impact on leaf surface structure.3. We identified the Ty-1, Ty-2 and Ty-3 resistance genes of resistant and susceptible tomato materials to tomato yellow leaf curl virus using PCR method in the research, and verified the resistance in the field by nature infection. The results showed that PCR method can rapidly and accurately detect resistance genes among the different tomato germplasm resources, and the materials which contain both Ty-1 and Ty-3 resistance genes have stronger and more stable resistance; and Ty-1 and Ty-3 resistance genes are incompletely dominant inheritance. So on the process of breeding, PCR method can rapidly distinguish the different resources of resistance, the breeders can combine the resistance genes in a single genotype to reach the maximum level of resistance.