Cloning And Analysis Of Dreb2Genes From Leymus (Poaceae:Triticeae)

Plants are exposed to environment stresses such as drought, high salt, and low temperature, which cause adverse effects on the growth and development of plants. These damages to plant caused by abiotic environmental stresses have been the important factors limited productivity of crops, improvement of ecological environment and sustained development. Therefore, it is a key and fundamental work for future agriculture to reveal the responsive mechanisms of plants to adverse environment stresses and enhance the ability of crops to tolerate abiotic stresses, which could meet the food needs of increasing population in the world.A transcription factor can control the expression of a number of downstream genes, thereby improving plant resistance. DREBs (dehydration responsive element binding protein) are a type transcription factors related to abiotic stresses. These proteins are able to discern and bind the DRE cis-element the promoter of some genes concerned with cold, drought and high-salt stresses, resulting in initating the expression of these genes at transcription level. Therefore, it would be a good strategy to improve tolerance of various kinds of agriculturally important plant to abiotic stresses by DREB genes transfer.Leymus Hochst. is an important perennial genus of Triticeae Dumortier (Poaceae), which are important genetic resource to Triticeae crops and forage grass resource. Leymus species normally grows on the beach, rivers and lakes sandy desert dunes, grasslands, meadows, hill and forest. Some Leymus species bear such desirable traits as bigger spikes, more and bigger grains and efficient photosynthesis. Meanwhile, most Leymus species have a strong cold, drought, alkaline, disease resistance, insect resistance, resistance to the capacity of sand.Using RT-PCR methods, we obtained a cDNA clone and15DNA clone encoding a new DRE-binding protein in Leymus. The Leymus DREB2has a completed ORF, being834bp in length and encodes a deduced protein of264amino acid residues. It is shown from Protein Blast data that this protein belongs to a typical member of the EREBP/AP2transcription family with conserved NLS, AP2DNA-binding domain and acidic redion. Genomic DNA structure analysis of LmDREB2indicated that there should be no intro in the genomic DNA of the LmDREB2gene. The tissue organ-specific expression pattern of the LmDREB2showed that its transcripts were detected abundantly in leaves and stems, and weakly in roots. So research the Leymus about stress genes is of great significance.Analyze16species of Leymus DREB2transcription factor nucleotide sequence and amino acid sequence. The similarity of nucleotide sequence and amino acid sequence are97.52%and97.04%, respectively. Phylogenetic trees of DREB2can well separate each species and reflect the phylogenetic relationship of Leymus species. Phylogenetic relationship of DREB2is basically coincidental with gliadin, RAPD and Acel geneAll the results above would lay down the basis for further research on the tolerance of Leymus to abiotic stresses and wheat improvement by genetic engineer.