Document Type: Research Paper
Faculty of Science
Background: TRR14 protein is a small member of a multi-gene family in Arabidopsis and is the first ones found during screening of seedlings for their resistant to the trehalose sugar.
Objectives: Characterization ofTRR14 over-expressed plants with respect to morphological changes, growth and photosynthesis related parameters.
Materials and methods: TRR14gene was isolated from Arabidopsis and cloned intopBin-35S vector. Recombinant vector was transferred to Arabidopsis (Col-0) via Agrobacterium tumefaciens by Floral Dipping method. Seeds from TRR14over-expressed (TRR14) and Col-0 wild type (WT) plant were sown on soil under long day conditions. Several measurements was then performed such as determination of fresh and dry weights, leaf area, Chl a and Chl b content, Chl a/b ratio, total chlorophyll and carotenoids content, soluble and insoluble sugars content, total and soluble protein content, the Hill reaction rate, chlorophyll fluorescence and photorespiration rate. Meanwhile, the chloroplastic proteins were investigated by SDS-PAGE analysis.
Results: TRR14 plants showed significant increase in both fresh and dry weights, leaf area, total and soluble protein content and significant decrease in insoluble sugar contents, compared to WT plants. Chl a, Chl b, total chlorophyll content, Chl a/b ratio, carotenoids content, Hill reaction rate, chlorophyll fluorescence had not showed significant differences between TRR14 and WT plants. The SDS-PAGE gel electrophoresis of chloroplastic proteins showed one ticker band with a molecular mass of 25kDain TRR14-over expressed plants, compared to WT plants. Remarkably, Photorespiration rate was decreased in TRR14 plants compared to WT plants.
Conclusion: The increased biomass of TRR14 transformed plants may be due to its ability in reducing photorespiration through concentrating CO 2 in the leaf intercellular spaces.