| Dehydrin is a kind of functional proteins, which is induced by abiotic stresses. In order to characterize the function of dehydrin genes in wheat, and provide the theoretical basis for further molecular breeding of stress resistance, with Luohan 2 as material, a new Dehydrin gene TaDHN-2 was cloned by using RT-PCR; the expression profile under ABA, PEG and NaCl treatments were analyzed, and the function was detected in vitro. The results showed that TaDHN-2 encodes 152 amino acids, including a Y(VDEYGNP) and S(SSSSSEDDGMGGRRKK) segment in N-terminus, as well as, two conserved K segments(KIKEKLPG) in C-terminus. These characteristics indicated that TaDHN-2 belongs to subclass YnSKn of dehydrin family. The expression profiling revealed that TaDHN-2 was induced by plant hormone ABA, which implied this dehydrin is regulated by ABA dependent signal pathway. Under the osmotic stress, the dehydrin gene demonstrated different expression patterns between two wheat cultivars, CS(Chinese Spring) and LH(Luohan 2). In root tissues, TaDHN-2 was up-regulated when induced by osmotic stress, significantly higher in CS than that in LH, while in leaf tissues, the expression level is higher in LH. In order to validate the activity of TaDHN-2, the protein was expressed in E.coli and purified by affinity method. Interestingly, it was found that TaDHN-2 with the concentration of 100 μg·mL-1 effectively increased the activity of α-amylase by 2 times at 60 ℃. Additionally, under the low temperature condition of 4 ℃, the activity of α-amylase was not increased until the concentration of TaDHN-2 over 20 μg·mL-1, and the enzyme activity was increased by 1.6 times when the concentration of TaDHN-2 reached to 100 μg·mL-1 . The results indicated that TaDHN-2 has protective effects on enzyme activity. |
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