Transcription Of The Dehydrin Like Gene WZY1-1 And The Physiological Indexes In Wheat During Drought Stress

Plant has often been effected by drought stress during it's growing process. Many genes can be induced by drought stress. Dehydrin gene is one of them, it belongs to LEA D11-family group(late embryogenesis abundant proteins)and it can be induced by many stresses such as drought,salinity and low temperature et al. It has many hydrophilic amino acid, and so it shows high hydrophilic. It can be functioned as a stability substance for nucleic acid and large cytoplast molecule. Drought stress could cause water lose of the plant cell, destroy the external hydration protective system of the double molecular layer of the lecithoid membrane, and also destroy the structure of the molecular. Dehydrins, due to it's high hydrophilic, it can combine with the lecithoid membrane thereby to prevent the water lose of the interior cell, maintain the hydration protective system of the membrane structure, avoid the decrease of the distance between the double molecular layer of the lecithoid membrane, farther to prevent the fuse of the membrane and the wreck of the biology membrane structure. During drought stress condition , many anti-drought related gene can be induced and expressed in plant, besides, many physiological indexes changed obviously, such as the water potential,proline content. To maintain high water potential of the plant leaves is an important physiological mechanism of the plant'anti-drought character, the proline take part in the plant's osmotic adjustion during drought stress, It maintains the pressure of cells during the decline of water potential by lowering the osmotic potential.The metarials used in this study were drought resistant wheat species zhengyin 1# and drought sensitive wheat shaanhe 6#. By using RT-PCR, we investigated the expression of the dehydrin-like in the leaves of wheat zhengyin 1# during drought stress with the control geneα-Tublulin. We also studied the expression of the drought induced dehydrin-like gene WZY1-1 and the variation of the water related physiological indexes in less drought tolerance zhengyin 1# and more drought tolerance shanhe 6# wheat during water stress condition with RNA-blot. The aim of this study is to gain the relationship between the gene expression and the drought tolerance of wheat. Thus to provide a base for anti-drought mechanism and the wheat breeding work.Meanwhile, we amplify the 3'end of the dehydrin like gene WZY1-1. The main results of this experiment are as follows: 1. Semi-quantitative RT-PCR of the zhengyin 1# wheat shows that: the dehydrin gene began to express after 18h of 0.5MPa PEG6000 stress, disappeared quickly after rehydration.2. In order to gain the dehydrin gene expression during drought stress in different drought tolerance wheat, we use RNA-blot by using the dehydrin gene WZY1-1 as probe. The results showed: the dehydrin like gene wzy1-1 didn't express in the well watered wheat, but the mRNA has expressed after 24h drought stress treatment both in zhengyin 1# and shanhe 6# wheat and the amount was higher in shanhe 6#. The expression time was earlier in more drought tolerance shanhe 6# wheat than in less drought tolerance zhengyin 1# wheat.3. The water potential of the leaves and the proline concentration analysis of the two different drought tolerance wheats showed that: During drought stress treatment. the water potential declined obviously, and raise up quickly after rehydration, nearly equaled to that of the well watered group. the water potential variation during drought stress condition was more obviously in drought sensitive wheat than in drought resistent ones. the proline concention in the leaves of the wheat was low under the well watered condition, it enhanced from the 18h drought stress time point and decreased quickly after rehydration treatment.During drought stress condition, the time when the proline concentration began to increase was also the time when the gene began to express. After rehydration, the expression of the gene disappeared as the proline concentration decreased. The amount of the gene expression was more and earlier in the more drought tolerance wheat shaanhe 6# than in the less drought tolerance wheat zhengyin 1#. Indicate that there was a relationship between the gene expression and the biochemistry substance, the expression of the gene may play an important role in maintaining the normal development of the plant during drought stress condition.4. 3'amplification of the dehydrin-like gene WZY1-1. We has gained a gene sequence a few amino acid longer than the dehydrin-like gene WZY1-1 by amplification of the cDNA from the stressed group with sense w41035 and anchor anti-sense, but the 3'total sequence didn't obtained. By analysis we find that: sense w41035 also performed as anti-sense, thus prevent the combine of the anchor anti-sense with the 3'end. The problem was solved through changing the sense w41035...