The Genetic Transformation And Functional Analysis Of GmFtsH

FtsH is ftsH gene-encoded ATP and Zinc-dependent multifunctional protein, which has ATPase activity, proteolytic activity and chaperone-like activity. FtsH participates in regulation of a variety of physiological metabolism and is in close association with adversity stress in plant. Existing studies suggested that FtsH involved in degradation of the photo-oxidation damage of PSII core protein D1 and was one of the key factors that helped plant resist to photoinhibition and restore the normal function of PSII. The function of ftsH gene in soybean remains largely unknown. Therefore, the present work is designed to clone soybeany ftsH gene, and to analyze its bioinformatical property and its function in transgenic tobacco. The results are as follows:1. The full length of GmFtsH gene was cloned from soybean species, Kefeng 1. Multiple sequence alignment analysis showed that GmFtsH was homologous to FtsH gene from other plant species. They shared common conserved domains and belonged to AAA protease family. By searching the soybean genome database with GmFtsH clone as query sequence, we found that GmFtsH was localized at Chromosome 15, including 4 exons and 3 introns in the coding region. Phylogenetic analysis indicated that GmFtsH had close genetic relationship with AtFtsH2, AtFtsH8, and Nt1.2. Photo-oxidation stress and drought stress were introduced to the seedling of Kefeng 1 to analyze for fluorescent quantitative expression of GmFtsH in different tissues. The results indicated that under the condition of photo-oxidant MV, expression of GmFtsH was up-regulated in root and leaf time-dependently, while it was firstly down-regulated in stem and up-regulated after 4 hours. After 12 hours, expression levels were 8-fold higher than initial expression levels, indicating that expression of GmFtsH was triggered by MV and closely related to photo-oxidation stress. Under the condition of drought stress, expression in root and stem did not change significantly with time, while expression in leaf increased in a time-dependent manner. These results indicated that expression of GmFtsH in leaves was triggered by PEG6000 and related to drought stress, raising the possibility that the regulatory site was localized in leaf.3. Plant expression vector was constructed to genetically transform tobacco with GmFtsH gene by using Agrobacterium-mediated leaf disc method. Positive transgenic tobacco was identified and evaluated for resistance to drought stress and oxidation stress. The results showed that the resistance to drought stress and oxidation stress was enhanced in the transgenic tobacco.