The expression of carrot antifreeze protein enhanced chilling tolerance in heterologous host system tomato and AFP can be a potential gene candidate for producing chilling tolerant crop plants.

In an attempt to improve chilling tolerance, the carrot gene encoding the antifreeze protein (AFP) was cloned under the control of constitutive CaMV35S promoter and genetically transformed the tomato var. PKM1 using Agrobacterium-mediated genetic transformation. Putative transgenic plants were confirmed by PCR using AFP-specific primers and grown to maturity. The integration of AFP transgene in the tomato genome was confirmed by Southern blot analysis. The AFP gene expression in transgenic plants was determined using semi-quantitative reverse transcription PCR. Upon exposure to chilling stress (4��C), a significant decrease in membrane injury index was observed in AFP transgenic tomato lines without any phenotypic aberrations when compared with WT plants. Hence, this study clearly proves that the development of chilling tolerant tomato plants will soon become a reality.