Cloning And Study Of 3-deoxy-D-arabino-heptulosonate 7-phosphate Synthase Gene Under Abiotic Stress In Hevea Brasiliensis

The rubber planting area of China belonged to the world’s northernmost, which is non-traditional rubber planting area. The growth of the rubber tree are susceptible to the wind, cold, drought and other environmental factors. Therefore, to improve rubber stress resistance of rubber tree is the main breeding goal of rubber tree breeding in our country.The shikimate pathway is associated to plant resistance. The main trunk of the shikimate pathway consists of reactions catalyzed by seven enzymes.3-Deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAHPS) is the enzyme that catalyzes the first step of the shikimate pathway, playing the vital role in the control chorismate biosynthesis.The study of the key enzyme in shikimate pathway is helpful to understand the mechanism of plant stress resistance.In this study, we successfully cloned DAHPS gene in rubber trees by RACE.The gene is named HbDAHPS, which contained a 1635bp ORF, and encoded 544 amino acid. Bioinformatics analysis showed that the molecular weight of HbDAHPS protein was 60.16 KD and its isoelectric point was 8.69. The full DNA of HbDAHPS was 4556 bp, and there were five exons and four introns in HbDAHPS gene. Bioinformatic analysis of the HbDAHPS gene shows that the encoded protien is a non-secretory cytoplasmic protein and localized in chloroplast. And HbDAHPS has one conservative domain belonging to the DAHP synthetase class II super family.The expressions of HbDAHPS in different tissues and under hormones, drought, low temperature and other abiotic stresses were analysed by real time fluorescent PCR. The results of qRT-PCR showed that HbDAHPS could express in leaves, bark, flower, latex and immature embryo, and among these tissues, there is the highest expression level of HbDAHPS in flower and the lowest expression level in latex. The expression in leaves of HbDAHPS could be induced by hormones, drought、salt and low temperature stress, and it was significantly up-regulated under MeJA, ETH, drought, PEG and low temperature stress. The expression in bark of HbDAHPS changed little.In order to investigate its function under abiotic stress, HbDAHPS was cloned into the expression vector MSP promoter-drived pCAMBIA2301-MSP and overexpressed in Arabidopsis thaliana. Using the model plant Arabidopsis which has clear genetic background to study the HbDAHPS response mechanism to stress. The results show that the HbDAHPS overexpression enhanced drought, salt and cold resistance of Arabidopsis plants.