Functional Investigation Of Banana MaEF1A

Banana is one of the world’s largest biomass of tropical fruit trees. High temperature and drought are its major growth limiting factors. Isolating key genes which control plant growth and development and investigating their functional mechanism have very important significance for improving banana yield and quality. Elongation factor (EF) can transfer the GTP and aminoacyl-tRNA to the ribosome and drive the extension of amino acid chain and control protein synthesis. Therefore, plant elongation factor is not only protein synthesis factor but also cytoskeletal protein and play important role in plant cell. However, the function and mechanism of banana elongation factor remain unclear.Based on our previous result of isolating an elongation factor1A gene named MaEF1A by screening postharvest banana fruit cDNA library method, expression characteristics of MaEF1A in different organs and under different treatments were investigated in this study. The possible interacting proteins with MaEFIA were obtained by yeast two hybrid. MaEFIA was transformed into Arabidopsis to further identify its function and mechanism. The results were obtained as follows:1. The expression result of MaEF1A in different organs indicated that MaEFIA was constitutively expressed. However, the highest expression level was observed in ovule4stage, and then roots, leaves and flowers, which suggested that MaEF1A play important role in these organs.2. The expression of MaEFIA in postharvest banana fruit was greatly induced by exogenous ethylene and suppressed by1-MCP, which suggested that MaEFIA be closely related with postharvest banana fruit ripening.3. The expression of MaEFIA in banana seedlings was greatly induced by salt stress and suppressed by low temperature. However, the expression of MaEFIA in banana seedlings changed little under flooding and damage. These results indicated that MaEFIA might be involved in the responses of salt and low temperature.4. MaEFIA was used as bait and prey cDNA library was constructed by using ovule4stage fruit. Two proteins might interact with MaEF1A were obtained by yeast two hybrid. This result indicated that MaEFIA might interact with these proteins to further regulate plant growth and development and response to stresses.5. Four dependent MaEFIA transgenic Arabidopsis lines (9,13,21,26) were obtained. The result of phenotypic analysis indicated that the plant height, root length, weight per plant and leaf number in transgenic lines were higher than that of control, which suggested that over expression of MaEF1A in Arabidopsis can promote plant growth and development.