Effect Of High Temperature On Rice Seed Set And Screening Of Specially Expressed Genes Under High Temperature

Studies of effect of high temperature on seed set and specially expressed genes under high temperature will be helpful to understand the mechanism of high temperature effects and develop heat tolerant rice. In this paper, a population of recombinant inbred line (RIL) was studied, which named as RIL47 and derived from a cross of indica variety 43S and a javanica variety 770. The RILs were treated with high temperature in phytotron at heading stage and seed set of RILs were measured at dough stage. For understanding mechanism of high temperature tolerance, mRNA differential display technique was used to study difference of expressing and to screen fragments of specially expressed genes under high temperature. Results of trial were as the follows:1 A set of valid data were gained from 107 RILs and the results showed that the heat injury index of 07C1507 (name of RIL, the same as follow) was the lowest, but it was considered to be useless because the seed set of both high temperature and natural temperature were very low. The seed set of 07C1590 was the highest under high temperature and also the heat injury index was lower in 107 lines. It was considered to be a good line to develop high temperature tolerance varieties.2 mRNA differential display technique was used to study the panicle of 07C1590 treated with high temperature. Fifteen differentially expressed DNA fragments were obtained, eight of them derived from pairs of random primer and anchor primer, and others from pairs of random primer and random primer.3 The further results demonstrated that seven fragments derived from pairs of random primer and anchor primer were approved truth by reverse northern dot blotting, and five of them were specially expressed under high temperature, two of them under natural temperature.4 Results of homological analysis indicated that:(1) e9-H, g6-H, g7-H, i9-H and k4-N were highly homologous with sequences in databases of mRNA and EST, but highly homologous sequences were not founded in database of proteins and the function of them could not be defined now. (2) The highly homologous sequence of f9-H was not found in database of mRNA, and a highly homologous sequence was founded in database of EST but the function was not explained. So f9-H was considered to be a fragment of new gene. (3) The protein sequence of k7-N was highly homologous with that of NADH dehydrogenase subunit K.