Overexpression Of Ammopiptanthus Mongolicus Defensin Gene (AmDE1) And Cold Shock Protein Gene (AmCSDP) Confers Abiotic Stress Resistance In E.coli And Arabidopsis

Ammopiptanthus mongolicus is an evergreen shrub of Leguminosae,distributing in Inner Mongolia,Ningxia,Gansu of China and Republic of Mongolia.A.mongolicus is a good sand-fixing plant which is living in the dunes and riverside terraces and resistant to drought,high salt,high temperature and freezing stress.In the meantime,it is an important woody plant with stress-resistant genetic resources.On the basis of the previous research,defensin gene and cold shock domain protein gene in A.mongolicus were transferred to E.coli and Arabidopsis by transgenic method,and their abiotic stress resistance were explored.The main results are as follows:1.Five defensin gene members were screened from the previous transcriptome data of A.mongolicus flowers,named AmDEI,AmDE2,AmDE3,AmDE4 and AmDES.The number and position of cysteine after sequence alignment,the conservative domain analysis,and the Logo map analysis proved that the five genes encode defensins.The phylogenetic tree indicated that the five defensins can be identified as the second class of plant defensins.qRT-PCR analysis showed that the expression levels of the five defensin gene members in roots and leaves were significantly different in responding to abiotic stress,indicating that the defensin family may evolve a synergistic mechanism in defensing the harsh environment.2.To analyse the function of defensin gene,AmDE1 was transformed into E.coli.The bacteriostatic test proved that AmDE1 can inhibit the growth of E.coli.Furthermore,AmDE1 was transformed into Arabidopsis,and the fluorescence localization results showed that AmDEl was localized in the nucleus and cytoplasm.The germination rate and seedling survival rate of transgenic Arabidopsis were higher than those of wild-type Arabidopsis after abiotic stress treatment,proving that AmDEl gene can improve the resistance of Arabidopsis to salt,osmotic and freezing stress.3.To reveal the role of AmCSDP in abiotic stress resistance,AmCSDP was transformed into E.coli,the survival rate of transgenic E.coli was higher than that of E.coli transformed with empty vector after treatment with salt,osmotic and freezing stress.The AmCSDP gene was also transformed into Arabidopsis,and the seed germination rate and seedling survival rate of transgene Arabidopsis were higher than those of the wild-type Arabidopsis after osmotic and freezing stress treatment,but the results for salt stress treatment were opposite,which proved that AmCSDP gene can enhance osmotic and freezing resistance of Arabidopsis.In conclusion,this research provides useful genes and new information for breeding new abioticstress resistant trees,ornamental plants,or crop plants.