Expression And Resistant Function Analysis Of DREB Transcription Factor Genes From Wheat (Triticum Aestivum)

Abiotic stress, such as drought, salinity, high temperature and low temperature, which have been difficult to resolve in agriculture, seriously affect the crops production in the world. In recent years, much studies on cloning, expression regulation, signal transduction and functional analysis of resistant genes, provide great potential applications for resistance breeding. Transcriptional factors are an important regulate factors in plants and can regulate transcription and expression of downstream adversity gene in time and space. DREB belonging to AP2/EREBP family, have a typical conserved amino acid domain, can combine DRE specifically and activate expression of many downstream resistance genes to improve plants resistance. In this study, we screened interacting proteins by making use of several DREB genes in wheat, and observed performance under different stress through selected transgenic DREB wheat and Arabidopsis thaliana, in order to understand DREB genes function. All these can promote the molecule improvement of resistant wheat. The results are as follows:1. Screening proteins which are interacted with DREBT. We constructed wheat cDNA library, pGBKT7-DREBT vector and screened proteins interacting with DREBT by yeast two-hybrid-system. Those positive clones were grouped into 4 types of candidate proteins according to Sequencings and Blast. The majority of four types of proteins related to signal transduction and immunologic process through Homology Blast, which showed that DREBT maybe invovled in the signal transduction under adversity and play an essential role in regulating the expression of stress-resistance genes.2. Expression patterns of DREB genes in wheat under different adversity. By Real-Time PCR, we used different adverse treated wheat cDNA as templates to study the expression patterns of DREBT, DREBF, DREB5, DREB8, DREB10 and W42. The results showed that the induced time, space and the expression intensity of DREB genes in wheat are difference. Under salt, drought, high temperature, low temperature and MeJA stress, DREB genes could be strongly induced.3. Resistant analysis and selecting of transgenic DREB Arabidopsis thaliana. We selected transgenic DREBT, DREBF, DREB5, DREB8å'ŒW42 Arabidopsis thaliana and identified the drought, salt, high temperature resistance in T4 regeneration. The reults show that under high temperature and drought stress, the overexpression of DREB genes can strengthen the Arabidopsis thaliana resistance, but the salt tolerance was not obvious. The osmotic potential of transgenic DREB Arabidopsis thaliana was mostly lower than wild-type species, which showed that DREB can resist on external stress.4. Resistant analysis and identification of transgenic DREBT/DREBF wheat. The Bar gene test showed that the foreign gene of transgenic wheat was partly lost. The proline and relative chlorophyll content of transgenic DREBT/DREBF wheat were higher than CK, and the result of identification in greenhouse showed that the overexpression of DREBT/DREBF can improve overall agronomic traits, increase yield and strengthen drought resistance in wheat.To sum up, the DREB genes cloned from wheat have better function; especially DREBT and DREBF have great resistance to drought stress. Under high temperature, salt and drought stress, W42 had big superiority. All these can provid theoretics for resistance breeding and candidate genes for wheat transformation experiment.