Heterologous expression of the AtDREB1A gene in chrysanthemum increases drought and salt stress tolerance

DNA cassette containing an AtDREB1A cDNA and a nos terminator,driven by a cauli- flower mosaic 35S promoter,or a stress-inducible rd29A promoter,was transformed into the ground cover chrysanthemum(Dendranthema grandiflorum)'Fall Color'genome.Compared with wild type plants,severe growth retardation was observed in 35S:DREB1A plants,but not in rd29A:DREB1A plants.RT-PCR analysis revealed that,under stress conditions,the DREB1A gene was over-expressed constitutively in 35S:DREB1A plants,but was over-expressed inductively in rd29A:DREB1A plants.The transgenic plants exhibited tolerance to drought and salt stress,and the tolerance was significantly stronger in rd29A:DREB1A plants than in 35S:DREB1A plants.Proline content and SOD activity were increased inductively in rd29A:DREB1A plants than in 35S:DREB1A plants under stress conditions.These results indicate that heterologous AtDREB1A can confer drought and salt tolerance in transgenic chrysanthemum,and improvement of the stress tolerance may be related to enhancement of proline content and SOD activity.

DMA cassette containing an AtDREBIA cDNA and a nos terminator, driven by acauliflower mosaic 35S promoter, or a stress-inducible rd29A promoter, was transformed into theground cover chrysanthemum (Dendranthema grandiflorum) ''Fall Color'' genome. Compared with wild typeplants, severe growth retardation was observed in 35S:DREB1A plants, but not in rd29A:DREB1A plants.RT-PCR analysis revealed that, under stress conditions, the DREB1A gene was over-expressedconstitutively in 35S:DREB1A plants, but was over-expressed inductively in rd29A:DREB1A plants. Thetransgenic plants exhibited tolerance to drought and salt stress, and the tolerance wassignificantly stronger in rd29A:DREB1A plants than in 35B:DREB1A plants. Proline content and SODactivity were increased inductively in rd29A:DREB1A plants than in 35S:DREB1A plants under stressconditions. These results indicate that heterologous AtDREBIA can confer drought and salt tolerancein transgenic chrysanthemum, and improvement of the stress tolerance may be related to enhancementof proline content and SOD activity.