Effects of overexpression of glyceraldehyde 3-phosphate dehydrogenase gene OsGAPC3 on rice yield and quality

【Objective】To reveal the effects of 3-phosphoglyceraldehyde dehydrogenase gene（OsGAPC3） overexpression（OX） on rice growth and development as well as rice quality, which could provide genetic resources for the molecular design breeding of new varieties of high-quality and high-yield rice. 【Method】OsGAPC3 overexpression transgenic strain was created based on japonica rice Zhonghua 11. Statistical analysis was conducted on the agronomic traits and related yield traits of transgenic positive strains overexpressing OsGAPC3 and their negative strains. The differences in chalkiness in different parts of rice grain slices were observed using a optical microscope, and the chalkiness area of rice was recorded. The chalkiness degree of rice was calculated, and the quality traits（nutritional quality, appearance quality, cooking taste quality and processing quality） of transgenic rice overexpressing OsGAPC3 were detected and analyzed. The transcription levels of OsGAPC3 and amino acid permease（OsAAP6）genes in transgenic strains overexpressing OsGAPC3 were detected by real-time fluorescence quantitative PCR. 【Result】Three independent transgenic positive strains overexpressing OsGAPC3 gene were obtained OsGAPC3（OX）-1, OsGAPC3（OX）-2, OsGAPC3（OX）-3). The expression level of OsGAPC3 gene in OsGAPC3 overexpressing transgenic positive plants（T₁ generation） was detected by real-time fluorescence quantitative PCR. The results showed that the relative expression level of OsGAPC3 gene in the 3 positive strains was extremely significantly higher than that in the negative strains（P＜0.001）. Compared with the negative strains, the positive strains（T₁ generation） showed extremely significant increase in tiller numbers（P＜0.01） and significant decrease in the number of spikelets per spike（P＜0.05, the same below）. There were no significant differences in plant height, seed setting rate, thousand grain weight, and yield per plant（P＞0.05, the same below）. The chalkiness rate significantly decreased, while the chalkiness area, chalkiness degree and grain type did not show significant changes. The content of amylose was extremely significantly reduced（P＜0.01）, and the rate of whole rice was significantly increased. There were no significant changes in total amino acid content, total starch content, free fatty acid content, gel consistency, gelatinization temperature, taste value, brown rice rate and milled rice rate. Compared with the negative strain, there was no significant difference in the relative expression level of OsAAP6 gene among the 3 transgenic positive strains overexpressing OsGAPC3. 【Conclusion】Overexpression of OsGAPC3 gene can significantly improve the appearance and processing quality of rice, without affecting its rice nutritional quality and yield per plant. The OsGAPC3 gene positively regulates rice tillering and can be used for research on rice growth and development, especially in high-yield variety breeding.