Analysis Of Transcriptional Expression Characters And Sequence Analysis Of Nitrogen Metabolism Key Enzymes Genes Involved In Japonica Hybrid Progeny

Rice protein is not only important nutritional quality traits, but also affect the important traits of rice cooking and eating quality. Now clear, glutamine synthetase, ammonium transporters proteinase, proteolytic enzymes as a key enzyme in the metabolism of nitrogen during the grain grouting and accumulation of protein synthesis plays an important role, closely related to the level of grain protein content. On the other hand, sexual hybridization between species is still present and the future is the main way to cultivate new rice varieties. Therefore, the study of the process of grouting the mature rice hybrid offspring activity changes in nitrogen metabolism and gene expression characteristics and analysis of sequence variation in genes, elucidate the molecular mechanism of grain protein content in rice hybrid offspring and genetic variation in rice quality breeding has important theoretical and practical significance.The contents of protein show obvious differences and Parents and generations of F10with similar genetic background combination I DongNong423x TengXi180and the combination II XiXuan lhao x Tong769), pot experiment was conducted systematic comparative analysis of the rice cooking and eating quality traits of grain grouting process and proteolytic enzyme glutamine synthetase activity changes, the key enzyme in nitrogen metabolism gene family mRNA expression patterns and glutamine synthetase gene sequence variation characteristics, Effects of Nitrogen nutrition on these traits and mRNA expression levels of genes, designed to provide a theoretical basis for elucidating the molecular mechanism of rice grain protein content in hybrid progeny of genetic variation and transgressive quality rice breeding. The results showed that:Grain protein content between the parents there were no significant differences among its varieties hybrid offspring transgressive variation can be obtained by successive generations directional selection grain protein content. In both combinations, the descendants of grain protein content than low amylose content descendants low protein content, but taste value and RVA Properties highest viscosity, low viscosity and viscosity values but had a large drop, while viscous impairment of elimination and final viscosity peaks are small, indicating that the impact of straight grain starch content of the cooking and eating quality traits is greater than the protein content, thus reducing the straight grain starch content is more conducive to improving cooking and eating quality of rice.Grouting in the same period combination of Ⅰ and Ⅱ combination of low grain protein content and protein quality of the offspring of the parents is always lower than the accumulation of high protein content and parental generations, the level of grain protein accumulation mainly controlled by genotype. Nitrogen fertilization at heading stage can significantly improve the protein content of grouting grain protein content in different periods and rice.Combination of two different periods grouting the parental and offspring functional leaf glutamine synthetase activity consistent trend, with the grouting process leaves showed activity gradually decreased, while the performance is increased with grain grouting process activity gradually declined after reaching a peak, showed a single peak curve.Activity of both the size of combination of performance, grain protein grouting different periods high levels of functional leaves parents and offspring glutamine synthetase activity grain protein content lower than parents and offspring activity is high. Grain protein synthesis and accumulation mainly in the early filling stage and grain filling stages high protein content offspring glutamine synthetase activity was significantly greater than the low protein content of future generations. Proteolytic enzymes in the latter part of the role of rice growth is strong, can promote the decomposition of protein. High protein content in grouting process generations proteolytic activity is always higher than the low protein content of future generations; nitrogen fertilization at heading stage can significantly improve the leaves and grain filling in different periods and proteolytic enzyme glutamine synthetase activity.Parental and hybrid offspring at different times grouting leaves glutamine synthetase and proteolytic enzymes in combination of I and Ⅱ portfolio trends are basically the same, with the grouting process gradually increased mRNA expression GS1.3gene expression to heading15-20days the highest, followed by decreased expression levels, showed a single peak curve, high protein content of GS mRNA transcription of the gene expression of offspring gradually increased, higher than the pro-. In combination Ⅰ,parental OsASP gene mRNA transcripts in the grouting process, the relative expression level is higher than the offspring, while the parent AMT5gene mRNA expression level lower than the offspring relative transcript. In combination II, the protein content is high in nitrogen metabolism of offspring relative mRNA gene expression of transcription is always the highest. Low protein content GS1.3gene transcription of mRNA expression of offspring relative low protein content is lower than the parental. Other nitrogen metabolism enzyme genes transcribed mRNA expression levels relative to higher parental. Heading stage nitrogen fertilization were transcribed mRNA expression significantly increased the amount of the nitrogen metabolism enzyme genes.The trials clones GS1.3and GS2gene sequences of length1113bp and1287bp respectively,371and429amino acids encoded. The nucleotide sequence has been published in GenBank comparisons, GS1.3in combination of II parents and offspring homology were99.7%,99.8%,99.6%,99.6%, GS2in combination of II parents and offspring were homologous99.9%,99.9%.100%,100%.Protein content between different rice varieties conserved glutamine synthetize gene is very high, but the differences between the varieties of any individual base still exists, but hybrids between species can still occur in the genetic bases stable separation and recombination process changes and changes in the triplet code, resulting in changes in the amino acid sequence and functional domains for the apparent sexual hybridization produces genetic Variation laid the intrinsic molecular basis.