QTL Mapping Of Soybean Rubisco Activity And Analysis Of Ftsh Gene Expression In Soybean [Glycine Max (L.) Merr.]

Photosynthesis is an important indicator of increasing crop productivity. Biological production is 90%-95% of the products from crop photosynthesis. Therefore, the key to increasing crop yields is to improve the utilization of light energy. As the key enzyme of photosynthesis Rubisco and an important gene FtsH of regulating photosystem II protein, they can have an important impact on photosynthesis of crops. Research against Rubisc and the FtsH family of crop photosynthetic traits has become a hotspot.Photosynthesis is a major target for improving crop productivity. D-ribulose 1,5-bisphosphate carboxylase/oxygenase （the Rubisco）, existing in the chloroplast stroma,is the key enzyme of Photosynthetic carbon assimilation in all photosynthetic organisms.At present, for the determination of Rubisco activity, there are three commonly used methods: isotope method,spectrophotometry method and non-radioactive microplate-based assay. The third way is a new method of non-radioactive microplate, using ELISA microplate reader and measured plate. Its high sensitivity allows the use of highly diluted extracts, and solves the problem of reaction time to avoid a long period of time due to repeated operation of the artificial error. Rubisco activity can be high-throughput determination by this way.On the other hand, FtsH is essential for the growth of many prokaryotes energy-dependent protease. Not only in vivo regulating the process of normal metabolism, but also in response to a variety of closely related stress. In higher plants, FtsH proteins involved in photo-oxidation damage D1 peptide degradation products, impacts plant photosynthesis. As the birth of the real-time fluorescence quantitative and gene-chip technologies, the whole genome level analysis of high-throughput gene expression profiles becomes possible. By the study on mRNA offtsH gene expression and other photosynthetic parameters, useing eQTL analysis of the differences in the level of gene expression of photosynthetic traits.Study results are as follows:1. High-throughput determination of activity of Rubisco and QTLRubisco activity was measured in the soybean system has been explored to determine the best reaction conditions by non-radioactive microplate-based assay. Using NJRIKY RIL （recombinant inbred lines）, Rubisco activity was determined, and the QTL Located. Rubisco activity found in control site on the A2, C2 and F linkage group, and the host range of the marker is BE820148-AW13240, satt658-satt316, sat₃12-sat₂52 and satt659-sat₁54.Total phenotypic variation can explain 32.94%. Individual contribution rate of 7.42-9.11%.2. Analysis of soybean ftsH cloning and expressionWe got the full-length sequence of ftsH gene, named GmFtsHl through homologous cloning from soybean. Sequence analysis showed that the fragment 2210bp in length containing a complete ORF 2070bp encoding 690 amino acids. Database searching suggested GmFtsH1 shared high sequence similarity with plant Zea FtsH6, Nicotiana tabacum. FtsH-like and Arabidopsis AtFtsH6, AtFtsH8. Thus we concluded GmFtsHl gene might be the homolog of ftsH in soybean.By the quantitative fluorescence method, GmFtsHl recombinant gene in soybean NJRIKY self-expression groups were determined. Recombinant GmFtsHl gene in soybean NJRIKY self-expression groups with fast chlorophyll a fluorescence transient （OJIP） PIABS and TRo/ABS were significantly correlated, with ETo/Tro was positively correlated.Two eQTLs associated with GmFtsHl mRNA expression were detected in NJRIKY. They are located in linkage group A2 and D1b+W. The marker interval were BE820148-sat₁62 and Rsc₇-satt157, the contribution rate is 6.63-7.96%.