Abstract:With radish seedlings and T1 rice lines overexpressing RsICE1 gene (a low temperature stress transcription factor encoding basic-helix-loop-helix from cold-tolerant radish) as materials,we studied expression profiles of RsICE1 gene,hereditary conditions of RsICE1 gene and expression conditions of cold regulatory genes in transgenic rice lines by semi-quantitative RT-PCR,molecule hybridization,and real time quantitative PCR.The results are as follows:(1)The semi-quantitative RT-PCR results suggested that RsICE1 was expressed constitutively in the examined tissues,such as roots,stems and leaves,and RsICE1 gene mRNA levels were dominant in roots and stems of radish seedling.The expression levels of RsICE1 were upregulated by cold and NaCl treatments,but not by the ABA and dehydration treatments.(2)χ2 test showed that the transgenic T1 rice lines existed resistant segregation model for 3∶1 ratio.The Southern and Northern blot analysis showed that RsICE1 gene had been integrated into the genomes of four cold-resitant T0 transgenic lines,and expressed normally.(3)Real time quantitative PCR results showed that after cold stress,overexpression of RsICE1 gene had no significant effect on the expression of OsDREB1A,OsDREB1B,OsDREB1F suggesting that the function of RsICE1 in cold stress was independent on the OsDERB1 cold responsive signalling pathway in transgenic rice.