Primary Study Of Differential Expression Of The Proteins In Endosperm Between Induced Autotetroploid Rice And Corresponding Diploid Rice

In research of the pecularity of induced new rice germplasms by chromosome sets-doubling technique is a new way in rice genetic improvement. New autotetraploid rice lines contribute to the research of yield potential and abandunce of rice germplasms resources on the polyploidy level. In our study, the diploid rice line Gui630 was induced to autotetraploid rice Gui630(4) by the seed-bud method. Main biological characters of rices with diffentent chromosome sets[Gui630(2) and Gui630(4)] were analyzed and protein expression profile of bigger seeds, smaller seeds and complemented strain during the process of inducement were observed. Protein expression level of duplicated genes after chromosome sets doubling was also studyed in this research. The main results are as follows:1. In order to study the effect on morphology resulted by doubling of chromosome sets, main biological characters were analyzed between Gui630(2) and Gui630(4). Our results showed that many biological characteristics changed greatly, such as lower plant height, stouter stem, higher grain length and grain width, higher 1000-grain weight. The new biological characters contribute to biomass yield and economic yield, and show a way for rice genetic improvement. However, Gui630(4) also show some adverse biological characters[such as shorter length of panicle, less secondary branches (rarer dentity of panicle), lower seed setting rate, et al.], which are new problems for the study of polyploid rice.2. Protein expression resultes of bigger seeds, smaller seeds and complemented strain during the process of inducement were analyzed. Protein content determination showed that the total protein content of the three plus trees of Gui630(4) and the total protein content of bigger seeds are significantly higher than that of Gui630(2). The protein content of each fraction in endosperm of most materials increase significantly, but the prolamin content of Gui630(4)B and the albumin, globulin content of Gui630(4)C show no significant difference compared to Gui630(2). The results of SDS-PAGE suggests that subunit types of bigger seeds, smaller seeds, complemented strain and Gui630(4)A, B, C show no significant difference compared to Gui630(2). In the case of smaller seeds, the 89kDa polypeptides was absent and the 54kDa was remarkably increased on the SDS-PAGE gels of total proteins. The subunit types of Gui630(4)C is different from Gui630(2). In the case of Gui630(4)C, the 89kDa and the 54kDa were absent on the SDS-PAGE gels of total proteins.3. In order to study the differential expression of the proteins in endosperm of rice with different chromosome sets, the present paper compared the major storage proteins in starchy endosperm of four autotetraploid rice lines with that of their corresponding diploid rice lines. The content of albumin, globulin, prolamin and glutelin in each sample was determined respectively. The structure and expression pattern of each storage protein was investigated using one-dimensional SDS-PAGE. Our results showed that the protein content of each fraction in endosperm of autotetraploid rice line is mostly higher than that of its corresponding diploid rice line. However, the SDS-PAGE analysis showed that the subunit types of each storage protein of autotetraploid rice line was generally homologous to that of its corresponding diploid rice line, except for one differential band observed on SDS-PAGE gels of total protein fraction and another on the SDS-PAGE gels of albumin and globulin fraction. These results indicated that duplicated genes in autotetraploid rice acquired the same expression patterns as that seen in its corresponding diploid rice. It was suggested that the doubling of chromosome sets did not change the protein expression profile but the protein expression level in the starchy endosperm of autotetraploid rice.