Cloning And Functional Analysis Of Drought-resistant-associated Gene TaSnRK2.3 In Wheat

Drought is one of the main factors to affect wheat yield (Triticum aestivum L).It adopts molecular biotechnology to utilize genetic resources of high-quality wheat and improve wheat drought resistance, which is the most effective shortcut to improve wheat drought-resistance and steady yield potenttial. Protein reversible phosphorylation is the key link of cell single transduction in almost all signaling pathways.Protein kinase (PK) plays an important role in signal transduction under abiotic stresses, such as osmosis, etc.The previous studies indicated that the expression of sucrose non-fermentation associated PK family (SnRK2) was induced by osmotic stress,and the wheat gene TaSnRK2.3 is one of the members in SnRK2 gene family.In this study, Hanxuan 10, a prominent drought resistance wheat variety, was used to isolate TaSnRK2.3 and characterize gene expression patterns under diverse stress conditions.The main results are following.1.The TaSnRK2.3 full-length CDNA was obtained by cloning, with open reading frame (ORF) is 1029bp,encoding a protein with-342 amino acids.The isoelectric point is 5.55,and molecular weight is 38KD.There exists the active site of serine/threonine protein kinase (PK).It has the closest genetic relationship with rice OsSAPK3,and the gene homology of SnRK2.3 in rice, corn and Arabidopsis thaliana is 84.7%,73,1%, 63.2% respectively.2.The TaSnRK2.3 have the highest expression level in leaf blade at jointing stage, and the lowest expression level in young ears at heading stage.The expression level is as follow:Spindle leaf at jointing stage> root of seedling> leaf of seedling> young ear at heading stage.The TaSnRK2.3 have different expression patterns under induction of response to exogenous gene ABA, low temperature, high salt and high-osmotic stress. In these four different processing modes,the sensitivity is as follow:High-osmosis> high-salt> ABA> low temperature.The expression levels of TaSnRK2.3 peaked for-PEG and NaCl quickly,and 24h fei ABA,and (?)e conespon(?)ing maxima were 25,25 and 5 times the check, suggesting that TaSnRK2.3 might participate in non ABA-dependent signal transduction pathways.The TaSnRK2.3 distribute on cell nuclei, cell plasma and cell membrane.3.During young seedling, the number of taproots and adventitious roots of transgenic TaSnRK2.3 in Arabidopsis thaliana plants is obviously more than in wild-type plants. In stress media, the seed germination of transgenic plants is obviously less inhibited than check plants.the chlorophyll content, maximal quantum yield of PS II photochemistry, water retention ability and osmotic potential of the transgenic plants have obviously stronger resistance than check plants.In adult period, the related resilience physiological such as free proline and cell membrane stability, and biochemical indexes and phenotypic data indicates the plants of transgenic target genes have obviously stronger resistance on high salt and drought stress than wild-type plants and empty-vector plants.Through detecting expression level of target genes in different transgenic strains, the higher expression level, the stronger capacity of salt and drought resistance in transgenic plants.The studies in this paper indicate that wheat genes TaSnRK2.3 participated response to osmosis and drought stress, and over expression of the genes can improve the salt and drought resistance for plants.