Transgenic Tobacco Expressing a Ring Domain-Containing Protein of Capsicum annuum Confers Improved Cold Tolerance

Zinc finger proteins function in plant tolerances to stresses from cold, dehydration, and salt. To determine the mechanisms for those underlying defenses, we previously used cDNA microarrays and northern blot analysis to identify a gene for the ring zinc finger protein (RDCP1) from hot pepper (Capsicum annuum). In that study, we showed that the RDCP1 gene was strongly induced by cold stress and, to a lesser degree, by ABA and high salt. Here, we have used a Ti-plasmid and Agrobacteriummediated transformation to engineer RDCP1 under the control of the CaMV35S promoter for constitutive expression in tobacco. The resultant RDCP1 transgenic plants exhibit significantly increased tolerance to low temperatures. Moreover, some of those transgenics have greater drought tolerance. In addition, none of the RDCP1 transgenic plants show any visible alterations from the wild phenotype. These current results demonstrate the biological role of RDCP1 in conferring stress tolerance.