Effect Of Tomato Drought Resistance And Differentially Expressed Genes Induced By Salicylic Acid And Calcium Chloride

Tomato is rich in nutrition, it is one of the most important fruit and vegetable crops around the world, also has an important position in China’s vegetable industry. However, almost all varieties of cultivated tomato in the whole growth period are sensitive to drought resistance, especially in germination and seedling stages. Therefore, the analysis of tomato drought-related morphological, physiological and biochemical indicators, have important theoretical and practical significance for the future production of tomato cultivation and drought tolerance mechanism. Currently, the study focused on the physiology and biochemistry of tomato under drought stress, few reports on molecular biology of tomato drought.This test researched the response of plants under drought stress by regulation of salicylic acid and calcium. By analysis morphological, physiological and biochemical indicators of tomato seedlings by exogenous salicylic acid and calcium chloride, find out the optimal drought concentration of tomato seedlings under drought stress. Meanwhile, we research the differentially expressed genes in tomato seedlings under drought stress by c DNA-AFLP technology, and fragments were isolated and sequenced on the basis of the above analysis. We expect to elucidate the molecular mechanisms at the molecular level of salicylic acid, ca lcium chloride induced in growth process of tomato seedlings under drought stress. Lay the foundation for understanding the tomato drought, provide a theoretical basis for the tomato yield and quality cultivation. The main findings include:(1)Spraying appropriate concentration of SA and Ca Cl2, eased the reduction of RWC in tomato leaves, reducing the relative conductivity and MDA content, at the same time, increased the contents of the relative chlorophyll, Pro and soluble protein, contributed to increase the activities of SOD, CAT, POD, and ultimately improved the drought resistance of tomato seedlings. For all the different concentrations of treatment, the better deals are 0.3 mmol·L-1 of SA and 10 mmol·L-1 of Ca Cl2. Comprehensive comparison, the effect of 0.3 mmol·L-1 of SA is more prominent.(2)According to the measurement results of physiological indicators, and combined with Observations of phenotypes, we got several key time points on drought, including 12 h, 24 h, 36 h, 2 d, 3 d, 5 d, 7 d. These time points also provide a basis for molecular test sample collection and analysis of gene expression patterns.(3)Tomato “DongNong 11537” was be treated, including normal control(CK1), drought control(CK2), the optimal concentrations of calcium chloride(C1 0), regular watering and spraying of the control treatment 10mmol·L-1 of Ca Cl2(CKC), the optimal concentrations of salicylic acid(S0.3), regular watering and spraying control treatment(CKS) 0.3mmol·L-1 of SA. Total RNA of different time points above six kinds of samples were analyzed by cDNA-AFLP technique, used EcoR I and Mse I. Selective amplification used a total of 256 primer combinations, this study screened 213 differentially expressed transcript-derived fragments(TDFs). Final secondary amplified fragment was 106.(4)The 106 differential fragments were sequenced, and sequencing results conducted nucleotide blast and blastx on the NCBI. The number of fragments successfully recovered is 90 except the TDFs of no match. And the obtained 90 TDFs are classified, including unknown genes, transcription factors, transferring transport, genetic information processing, signal transduction.(5)Six TDFs associated with drought resistance were quantitative PCR validation, the results are consistent with the c DNA-AFLP analysis. The results of this study are reliable. While using multiple time points for analysis in real-time PCR, further accessed the detailed expression patterns of the validated gene in tomato drought response procedure.