| Rice is one of the main food crops in the world, which provids a staple food for more than half of the human polulation. Starch is the main component of rice endosperm, which determines the fianl quality of rice. In this study, we introduced the overexpression construct of OsEBP89 gene into different rice varieties mediated with Agrobacterium. We also introduced the RNA interference structure of rice OsSSSII-2 gene into Kangtiaowuyunjing 8 line in order to improve the quality of the starch. After sevreal generations of selection by PCR, we had selected many transformants without selectable marker, and we carried out many experiments to analyze the expression of target gene and grain quality. The main results are as followings:1.10 and 9 selectable marker free Kangtiaowuyunjing 8-derived transformants were selected from the offspring of 21 independed OsEBP89-overexpression transformants and 30 independed OsSSSII-2-RNAi transformants, respectively. The frequency of selectable marker free transgenic lines obtained is 47.62% and 30.00%, respectively.2. We performed RT-PCR analysis to examine the expression of the EBP89 gene. We found that the expression of the EBP89 gene was improved in the selected trangenic lines containing the overexpression construct of OsEBP89 gene. And the expression of the SSSII-2 gene was reduced in the selected transgenic lines containing the OsSSSII-2-RNAi construct. Morever, the expression of Wx gene had non-uniform trends in the transgenic lines containing the overexpression construct of OsEBP89 gene, which was increased in Kangtiaowuyunjing 8-derived and Nipponbare near isogenic lines-derived, and decreased in Nipponbare-derived. And the expression of Wx gene in the transgenic plants containing the OsSSSII-2-RNAi construct was lower than the wild-type.3. In the physicochemical-quality analyses, the amylose content of the Kangtiaowuyunjing 8-derived and Nipponbare near isogenic lines-derived transgenic lines containing the overexpression construct of OsEBP89 gene showed variable levels of increasion, and their gel length was decreased differently. On the contrary, the amylose content of the Nipponbare-derived transgenic lines containing the overexpression construct of OsEBP89 gene showed significant decreasion, and the gel length of these transgenic lines became longer than its wild type. The amylose content of the Kangtiaowuyunjing 8-derived transgenic lines containing the OsSSSII-2-RNAi construct showed significant decreasion. And the gel length of these transgenic lines became longer than the wild type, significantly.4. The gelatinization temperature (GT) of the transgenic lines containing the overexpression construct of OsEBP89 gene were not significantly lower than the GT of the wild types. The GT of the transgenic lines containing the OsSSSII-2-RNAi construct were lower than that of the wild type, which indicated that the starch of the transgenic lines is easier to be gelatinzed.5. The RVA-paste viscosity of the transgenic lines was measured using a Rapid Visco Analyzer (RVA). The transgenic lines containing the overexpression construct of OsEBP89 gene showed slight variance in their mostly BDV, SBV, and CSV indices. The BDV values of the transgenic lines containing the OsSSSII-2-RNAi construct was increased, and the SBV, CSV were decreased significantly, which indicated that the taste quality of the transgenic lines was improved.6. Most of the agronomic traits of the trangenic lines containing the overexpression construct of OsEBP89 gene were comparable with those of the wild types. However, the plant height of the Nipponbare-derived transgenic lines containing OsEBP89 gene drived by Ubi promotor were lower than the wild type significantly. The grain weights of transgenic plants containing the OsSSSII-2-RNAi construct was lighter than the wild type, which might be due to the reduction in AC. In addition to the plant height, most of the other agronomic traits of the transgenic lines containing the OsSSSII-2-RNAi construct were comparable with the wild type. |
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