AcdS gene of Bacillus cereus enhances salt tolerance of seedlings in tobacco (Nicotiana tabacum L.)

Previous studies show that 1-aminocyclopropane-1-carboxylate (ACC) deaminase can facilitate the growth and stress tolerance of hosts by reducing ethylene levels. In this study, the acdS gene encoding ACC deaminase from Bacillus cereus (HK012) was cloned and transformed into tobacco (Nicotiana tabacum L.) by the leaf disc method using Agrobacterium. Molecular detection and physiological analysis of the transgenic tobacco plants were performed. Our results showed the acdS gene was integrated into the tobacco genome and fluorescence microscopy showed that the fusion protein was located on the cell membrane of tobacco root. Compared with control, the transgenic plants showed increases in plant height, root length, dry weight, fresh weight and chlorophyll content; and significant increases in the concentration of proline of 55.15% and 42.7% under salt stress conditions (150 mmol L-1 and 300 mmol L-1 NaCl, respectively). The superoxide dismutase, peroxidase, catalase and ACC deaminase activities of transgenic tobacco were higher than those of control tobacco at 150 and 300 mmol L-1 salt concentrations. Transgenic tobacco seedlings expressing the acdS gene of B. cereus HK012 showed higher salt tolerance than the control plants. The obtained results suggest that the acdS gene of B. cereus can be used to promote salt tolerance in glycophytes by using biotechnology strategies.