Rice is one of the most important cereal crops of high economic and social value feeding the population of about 6.8 billion people over the world. In the past decade, changes such as rapid economic growth, especially in parts of Asia, rising wage rates, increasing diversification of diets, global climate change, and a greater integration of the food economy with other sectors of the global economy, including both energy and financial markets, have converged to shape the way rice is produced today and will be produced in the future. One of the main constraint affecting the yield are abiotic and biotic stresses like drought, salt, cold stresses and diseases like blast. These affect both yield and plant growth Cold stress affects the rice crop at seedling, reproductive and ripening stages. Cold tolerance at these stages mainly seedling stage is an important parameter to reduce the rice productivity in NEHR.
Work at molecular level on the cold responsive genes has revealed role of genes, transcription factors (T 8) and quantitative trait loci (OTL ). Present study was carried out to find the novel genes, to validate the responsiveness in two rice landraces (UR5 and UR 17-2) adapted to low temperature by RT-PCR method and clone the selected genes into an appropriate vector. The genes were selected from the referred paper which provided 714 unregulated novel genes. Out of 10 selected genes, 6 showed amplification when standardized with genomic DNA. RT-PCR experiment showed that at 24 hours stress 2 genes (OsZim and OsFbx257) show differential expression. While at 3 hours 4 genes viz, OsPs, OsFbx257, OsZim and OsPal were differentially regulated. Based on RT-PCR data 4 genes (OsPal, Oszim, OsFbx257 and OsPs) were selected for cloning in TOPO-TA vector. The genes selected for cloning belong to different gene families viz, ZIM, TIGR01615, phenylalanine lyase and F-box. The OsFbx257 gene was successfully cloned. This gene could be evaluated further for its role in planta under low temperature. The role of ZIM, TIGRR1615 and Phenylalanine lyase like proteins in response to low temperature is not very well worked out in rice. These could be future research areas of interest.