Overexpression of Arabidopsis CBF1 Gene in Transgenic Furenzhi banana (Musa spp. AA group) Improves Resistance to Low Temperature

Abstract

Cold is an environmental factor that limits the growing season of banana and adversely affects fruit quality and productivity. C-repeat/dehydration responsive element binding factor 1 (CBF1) play important roles in the responses of plants to low-temperature and cold. To test the function and potential use of cold-induced factor CBF1 in improving the chill tolerance of banana, AtCBF1 driven by a cauliflower mosaic virus 35S promoter was introduced into banana plants by Agrobacterium -mediated transformation of embryogenic cell suspensions (ECSs) of banana cultivar Furenzhi (AA). The presence of AtCBF1 transgenes in regenerated plants was confirmed by polymerase chain reaction (PCR) and Southern blots. s-glucoronidase (GUS) histochemical assays reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR analysis demonstrated that foreign genes were stably expressed in regenerated plants. Transgenic banana showed growth retardation, thicker leaves and higher chlorophyll content than non-transformed plants. While relative electrolyte leakage (REL) and malondialdehyde (MDA) content were significantly lower in transgenic banana plants than in non-transformed plants under low temperature stress. An obviously higher cold tolerance was observed among the transgenic plants in the cold detection. These results suggest that over-expression of AtCBF 1 in transgenic banana plants plays an important role in improving tolerance to low-temperature.