Cloning And Functional Analysis Of GhHsfA7 Gene In Gossypium Hirsutum

Cotton is one of the most important crops in the world. Due to the worsening environment and the decreasing cotton planting area, improving the abiotic stresses tolerance has been a hot topic of cotton stress tolerance research.Heat shock transcription factor(HSF) is a family widely exists in plants that involved in various physiological and biochemical activities, including stress tolerance, plant growth and development, and signal transduction. However, there are few reports about the function of heat shock transcription factor in cotton.In this study, we cloned 29 members of heat shock factors from cotton. We analyzed the function of GhHsfA7. The main results as follows:(1) GhHsfA7 gene is significantly upregulated under high salt and drought stresses. The seedlings of upland cotton were treated by MS nutrient solution with 150 mM NaCl, 150 mM mannitol, and pH8.0 respectively. The treat time was 30 min, 1h, 2h, 3h and 6h. Then we extracted total RNA from root under different treatments, and analyzed the relative expression of GhHsfA7 gene by real-time fluorescent quantitative PCR. The result shows that under the treatment of 150 mM NaCl, 150 mM mannitol, and pH8.0, the highest relative expression of GhHsfA7 gene is 1.5 times, 3.5 times, and 5 times more than wild type plant.(2) Ecotopic expressed GhHsfA7 in Arabidopsis can improve its salt tolerance. We analyzed the phenotype between overexpression plants and wild type plants of Arabidopsis under adversity and found that: the physical signs including root length, fresh weight, dry weight and chlorophyll content of transgenic plant were 1.8 times, 1.7 times, 1.6 times and 3.4 times higher than wild type plant.(3) Colning and analysis the structure of GhHsfA7 gene promoter. The result shows that GhHsfA7 gene promoter contains some common elements such as TATA-box and CAAT-box, besides some adversity stress response elements including HSE, TC-rich repeats, WUN-motif, MBS, ARE, LTR and I-box, they are related to drought stress, low temperature stress, anaerobic and defense stress.All the results demonstrate that GhHsfA7 gene is involved in responding to different stresses, and ecotopic expressed Gh HsfA7 gene in Arabidopsis can improve its salt tolerance. This study makes a foundation for further research of regulatory mechanism of GhHsfA7 gene.