Cloning And Expression Analysis Of KdsA Gene In Mulberry(Morus Alba L.)

Mulberry is a perennial woody plant distributed widely in the world, which has a remarkable adaptability to the various environment. However, the knowledge of molecular mechanism related to adaptability for abiotic stress in mulberry is still limited, especially, the screening and cloning of stress resistance gene resources is rare, should to be further explored. Our laboratory had found that KdsA gene expression was decreased after drought treated in mulberry, and suggested KdsA gene maybe plays a role in the drought stress response. In order to make clear the relationship of KdsA gene in responsed to abiotic stress, in the present study, we cloned the full length of KdsA gene, and analyzed its expression pattern in responsed to abiotic stress. The results provided the clue to understand the molecular mechanism of mulberry responded to abiotic stress.The results were as follows:(1) The full-length cDNA sequence of the KdsA gene in mulberry was obtained by homology cloning, 3’ RACE and 5’ RACE, speculated that the gene encoding the protein sequence KDO8 Ps. Homologous alignment and phylogenetic analysis showed that the gene and its coded protein have a high degree of consistency with that of other plants, indicated that the protein is relatively conservative in the process of evolution, and suggested that the KDO biosynthesis pathway of evolutionary conserved features.(2) MaKdsA gene expression was detected by real-time PCR in cultivars such as Shin-Ichinose, Fengwei-Ichinose, Tiansang 1, Hongsang 32, Shiping, Dashi, Tongxiangqing, Shaansang 402, Jianchi, Hongguo 1, Shaansang 305, a total of 11 cultivars of mulberry, in which MaKdsA expression in Jianchi was the highest, and its expression in seedling and in Shin-Ichinose was the lowest, KdsA relative expression in other cultivars showed no significant difference. The KdsA gene expression was no significant difference among different weather conditions and different ploidy.(3) The relative expression of KdsA gene in the second leaf positions was significantly higher than that of the eighth leaf positions, suggested that expression of KdsA gene is higher in the young leaves, and is low in the mature leaves.(4) The expression of KdsA gene in mulberry was significantly decreased after drought and salt stress treatment, it is showed that the KdsA gene was related to the response of drought and high salinity stress.The test results suggested that the plants will down regulated KdsA gene expression induced by stress, such as drought and high salt conditions. The results of this experiment proved evidences that the expression of KdsA gene was consistent with the analysis of protein differences. KdsA gene was a drought stress responsive gene in mulberry. This experiment has important significance for the study of the stress mechanism of drought, salt and salt stress in stress signal responsibility.