Salt Tolerance Analysis Of AtNTL5Transgenic Festuca Arundinacea And Primarily Functional Analysis Of Soybean Salt Tolerence Re-sponsive Genes GmDREB1D And GmRF

Soil salinization has emposed tremendous negative impact on global agricultural production and severely reduced crop yields. Plants can adapt to the saline soil environment through a series of biochemical and physiological adjustment, and this characteristic of plants, as well as some excellent salinity plant germplasm can be employed to cultivate salt-tolerant crop varieties for the improvement and the use of saline-alkali soil.As the economic development and the quality of human life improvement, lawn grasses have been more and more used in living environment, urban public green space, gardens, golf courses and sports grounds and other facilities. Turfgrass demand has boosted the modification and screen of new types of lawn grasses. In this thesis a salt tolerance gene AtNTL5was transferred into Festuca arundinacea via agrobacterium-mediated callus transformation methods. And eventually29genetically modified plants were obtained, the transformation rate was9.7%. Salt tolerance assay proved that the ectopic expression of AtNTL5indeed enhanced the salt tolerance of transgenic Festuca arundinacea.Soybean is an important food crop. Cultivated soybean is a kind of moderately salt tolerant crop, so the soybean cultivation is seriously impacted by soil salinization. Our laboratory evaluated the salt tolerance of varieties of soybeans and found a salinity tolerance cultivar SHENGDOU No.9. Non-salt and salt stress gene expression profiling were performed for this soybean cultivar. Two up-regulated genes which encoding transcription factors GmDREB1D and GmRF were cloned and their function were preliminary explored.GmDREB1D encodes231amino acid residues and this protein contains an AP2/EREBP conserved domain. The yeast transcriptional activation assay proved GmDREB1D does have transcriptional activation activity. The semi-quantitative RT-PCR (sqRT-PCR) experiments of soybean revealed that GmDREBID was expressed in various organs, of which the higher expression levels were tested in the stems and leaves, suggesting that its expression may be associated with the soybean vegetative organs’ development and growth. The sqRT-PCR assay further showed that GmDREB1D responsed to ABA, salt and cold in transcription level. We hypothesized that this gene may be widely involved in the process of these hormones and abiotic stress signal transduction and regulation. GmDREBID overexpression transgenic Arabidopsis thaliana mature seedlings was short, slow-growing, bolting late or even not bolting for a lifetime and with dark green leaves, showing sluggish growth characteristics. There is a positive correlation between the gene expression level and the rossete size phenotype in GmDREB1D over expression seedlings. The expression of GmDREB1D could improve the salt and cold tolerance of transgenic Arabidopsis.GmRF encode a RING-FINGER protein which contains a C4HC3zinc finger motif and two C-terminal transmembrane domains. RT-PCR analysis of the different organs of soybean plants suggested that GmRF expressed ubiquitously and has no obvious tissue-specificity. GmRF responsed transcriptionally to ABA, salt and drought stresses and its ecotopic expression enhanced the salt and drought tolerance of transgenic Arabidopsis.