The Cloning Dehydrin Gene Wzy2 By Race And Analysis Of Free Amino Acids In Wheat Under Water-Stress

1. Dehydrins presence in almost all water-deficit plants, they were identified as the groupâ…¡of the LEA proteins, and have a wide range of molecular masses from 9 to 200 KD. These proteins can be found in the later maturation stage, in response to cellular dehydration caused by abiotic stresses such as low temperature, exogenous ABA, drought, high salinity where cellular dehydration occurs. Dehydrins are one of the proteins induced by water-deficit, structure analysis of plant dehydrins indicate they have the character of high hydrophilic and thermostable , due to these character they may play a impotent role when plants under environmental stresses.The objective of this study is to isolate and clone the dehydrin gene wzy2 from Zhengyin NO.1. The primers were designed by conservative region of dehydrins, using the method of RACE, with -0.5 Mpa PEG6000 stressed wheat seedlings, a full-length sequence of a new dehydrin gene was amplified; Analysis its endure drought function by bioinformatics soft. The dehydrin gene wzy2 cloned from Zhengyin NO.1provides further information on the structure of dehydrin and its possible function in plant tolerance to drought.The main results of this experiment are as follows:1). The wheat dehydrin gene wzy2 is a drought-induced gene, it expressed under water-stress, no express in normal watered seedlings.2). A full-length sequence of a new dehydrin gene was amplified; the gene has a length of 849 bp, including a 459 bp ORF (open reading frame). Analysis showed that the protein sequence of the gene encoded has the characteristics of dehydrin genes: the K fragment, S and Y fragment. It is an YSK2 dehydrin formed by two K fragments, an S and a Y fragment.3). Bioinformatics analysis of the protein encoded by dehydrin gene wzy2 indicated it has a molecular weight of 15.5 kD and an estimated pI of 7.17, is a neutral protein; the WZY2 protein including a hydrophilic region, near the 20th AA of the N end, the hydrophilic region can interact with hydrophobia AA residuals may help to prevent denaturalization of the membrane, stabilize the structure cell. In the deduced amino acids sequence of WZY2 protein, there're no Cys and Trp residues, but were rich in polar amino acids, indicating a high hydrophilic nature. The high hydrophilicity of the protein indicated it play an important role in binding the free water and stabilizing the membrane.2. Plants accumulating free amino acid as osmotic adjustment materials when under water-deficit. The accumulation of osmotic adjustment solute (soluble sugars, free amino acids and proline) was increased with the aggravation of water stress. They may play a key role in drought adaptation in arid environments.The materials used in this study were drought resistant wheat species zhengyin 1# and drought sensitive wheat shaanhe 6#. By mensurate the free amino acid of the wheat seedlings under water-stress, provide some farther information of the mechanism of nitrogen metabolize and protein synthesization, degradation.The free amino acids content of wheat seedlings when under water-stress were mensurated, its result indicated that the free amino acids content increased in leaves and roots both of the two wheat species; free amino acids in leaves is more than in roots'; compare the free amino acids content of the two species, zhengyin 1# lower than shaanhe 6#.