Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/8/2000
Publication Date: 1/9/2000
Citation: Vantoai, T.T., Zhang, J., Huynh, L.N. 2000. Tolerance of transgenic arabidopsis containing the sag12-ipt chimeric gene to abiotic stresses. Meeting Abstract. Interpretive Summary:
Technical Abstract: Environmental stresses cause premature senescence in plants that results in leaf chlorosis, necrosis, defoliation, cessation of growth and reduced yield. This study was conducted to determine the effects of autoregulated cytokinin production on the tolerance of Arabidopsis thaliana plants to flooding, drought, temperature and salinity stresses. A chimeric gene containing the senescence-specific SAG12 promoter and the ipt gene coding for isopentenyl transferase, a rate-limiting enzyme in the cytokinin biosynthesis pathway, was constructed. The chimeric gene was introduced into Arabidopsis plants by Agrobacterium-mediated vacuum infiltration. Four transgenic lines were chosen for environmental stress tolerance determination. DNA hybridization analysis and PCR confirmed that all four of the transgenic lines carried the ipt gene. The segregation of kanamycin resistance in the T2 generation indicated 1 to 3 integration events. GUS expression and RT-PCR of the ipt gene confirmed the senescence-specificity of the SAG12 promoter. Morphologically, the transgenic lines appeared healthy and normal. While all four transgenic lines were consistently more tolerant to flooding, drought and temperature stresses than wild-type plants, they were more sensitive to salinity stress. The results indicated that endogenously produced cytokinin can regulate senescence caused by water and temperature stresses, thereby, enhancing plant tolerance to flooding, drought, heat and cold. Tolerance to salinity, however, is regulated by a mechanism that probably does not involve early senescence and cytokinin production. This study provides a novel mechanism to improve the tolerance of plants to water and temperature stresses.