Expression And Preliminary Functional Analysis On Salt-tolerance Of MicroRNA398 In Tomato

Soil salinization have significant deleterious influences on a wide variety of crops in yield and quality, which has damage to the sustainable of agriculture. MicroRNAs have emerged as master regulators of plant growth and development, which has presented people a new understanding of post-transcriptional gene regulation in plants and animals. Evidence suggesting that miR398 mediates responses to biotic and abiotic stresses, including heavy metal, high salinity, high light, pathogens. At present, reports on stress responses of microRNA, tomato microRNA are rarely involved. We choose ‘Micro-Tom’ tomato as the test material, analyzed the expression of tomato microRNA398 and preliminarily analyzed its function in salt tolerance by bioinformatic and experimental biology methods. The main results are as follows:1.We predicted the two members of tomato miR398 family(sly-miR398 a and sly-miR398b) and four target genes(one CSD, two C2H2-type zinc finger protein genes, one CPR5 gene). By real-time quantitative PCR(qPCR) analysis, the level of sly-miR398a/b was the highest in tomato stem and CSD in the root.2.We cloned the over-expression fragment of sly-MIR398 a and sly-MIR398 b, promoter fragment of sly-MIR398 a. Then we constructed the corresponding plant over-expression vectors, obtained the corresponding transgenic tomato plants as well.3.The growth of tomato plants is restrained under NaCl stress. By qPCR analysis, the expression of sly-miR398 a, sly-miR398 b and CSD were up-regulated induced by NaCl in leaf and root; sly-miR398 a down-regulated, sly-mi R398 b has a smaller degree of increase than in the stem; CSD has no obvious change. It shows that sly-miR398 can be induced by NaCl.4.Under both GA and SA treatment, sly-miR398 a, sly-miR398 b and CSD have produced different patterns of response. It suggests that the sly-miR398 is also involved in plant signal transduction.