Functions Of Cotton CBF Gene Under Abiotic Stress Conditions And CBF Gene Cloning From Ammopiptanthus Mongolicus

Low temperature and drought are adverse environment conditions that affect the growth of plants and productivity of crops. Every year there is serious reduction of crop in agriculture because of low temperature and drought in the world. The stress tolerance in plants is controlled by several different genes. Transcription factor can activate a cluster of genes expression at the same times, this will induce the resistance of plants to the poor environment. As an abiotic stress-inducible transcription factor, CBF(C-repeat binding factor) can regulate expression of a number of genes and thus produce a series of proteins that widely participatein physiological and biochemical processes of stress tolerance and consequently improve comprehensive resistances of plant. CBF plays an important role in low temperature and drought tolerance. In Arabidopsis, CBF transcriptional factors perform this function by binding to the CRT/DRE, a cis-acting element present in the promoters of cold-regulated (COR) genes and then activating COR gene expression. The CBFs are not unique to Arabidopsis and have been identified in a number of species across the plant kingdom, and they have different regulating roles in different plants China has become one of the largest cotton producers in the world. Low temperature and drought causes the loss of cotton yield and quality. It is important work on the cotton CBFs and cotton stress tolerance. As the unique evergreen shrub in Chinese hungriness area, Ammopiptanthus mongolicus that develops high endurance to low temperature and drought is the optimal material of stress tolerance reaserch.In this work, the GbCBF1 gene coming from cotton Hai7124 was found to be cold, drough, ABA, and NaCl-inducible by Northern blot. It was put under the control of 35S promoter of cauliflower mosaic virus (CaMV) or NOS promoter respectively in binary vector pCAMBIA2301, and transfered into tobacco by leaf disc procedure. After molecular analysis of transgenic tobacco, physiological indexes test was performed. By determining the relative electronic conductivity, the content of free proline and soluble sugar and drought tolerance, it is proved that transgenic tobacco cold and drought tolerance was enhanced obviously. It is conferred that GbCBF1 may response the abiotic signal in tobacco. The full-length open reading frame of CBF cDNA was isolated by RACE strategy from Ammopiptanthus mongolicus. The result of semi-quantity RT-PCR that AmCBF can response to cold stress treatment, and reaches the maximum expression at 2h, indicates AmCBF may mediate in responsing to cold in Ammopiptanthus mongolicus and play a significant role.The AmCBF protein sequence was analyzed by bioinformatic methods, including AP2 domain and conserved short peptide sequence. AmCBF belongs to CBF family among AP2/EREBP family. The secondary and tertiary structure prediction of AmCBF are similar to these of GbCBF1, however, the diferrence of several amino acids between them presumably has influence on CBF protein binding ability.