Isolation And Functional Analyse Of AsEXP1 Promoter In Agrostis. Strain PenA-4

The drought is one of the key factors affecting plants'growth. In droughty conditions, plants' metabolism pattern changes, physical activity is inhibited, all the stages of growth is affected and appears to be wilting. Improving the arid tolerance of species by genetic engineering is an effective method to solve the problem.AsEXP1 is an expansin gene isolated from extreme heat-resistant species A. scabra which expresses in high temperature conditions. Once the expansin induced, it can loose cell wall, increase the extension of cell and relieve the tension to the cell wall, thus enhance the plants'ability to resist against the heat. Since the expansin can affect the adaptability of plants towards unfavorable conditions through regulating the cell walls'degree of expansion, we suppose the expressing of heat-resistant gene AsEXP1 also can enhance the plants'resistance capability on the drought, which needs to be further studied.For further studying on the functions of AsEXP1, the 962bp-length regulatory region in the upstream of AsEXP1 was cloned and conjoined to GUS gene to transform agro bacterium tumefactions which injected the rice callus. The analysis results prove that this region possess promoter activiities and is induced by high temperature. This region contains several basic transcription elements such as TATA box and AGAG box. In the core region of TATA box there are several cis-acting elements under the regulation of GA, ABA and drought conditions, which can lead to the conclusion that AsEXP1 is induced by GA,ABA and drought conditions. In addition, to build an over-expressing carrier of AsEXP1 to further analysis of its functions will lay the foundation to study on the mechanism of expansin regulating the plants'resistance and will lead the strategy of improving the grass production under unfavorable conditions to a new direction.