Study On Gene Hereditary Variation And Expression Characters Of Branch Enzymes Involved In Jponica Hybridprogeny

The contect of amylose is the most important norm, which decides the quality of cookingrice.Amylose is synthetized and accumulated throuth enzymatic reaction during the process of graingrouting. There are many kinds of enzyme synthetized from amylose, among them. rbe is one of thekey enzyme, which activity has close relationship with content of amylose.The contents of grain amylose show obvious differences and Parents and generations of F10with similar genetic background combinationⅠDongNong423×TengXi180and the combinationⅡ XiXuan1号×Tong769),the way of choose based on the difference of amylose content,anduse two-dimensional electrophoresis and mass spectrometry,Through the systematic potexperiment, it is compared and analysed expression profile of cooking and eating quality traits andyield traits,andincluding the active change of starch branching enzyme in the process of grouting,the mRNA expression profile of family of rbe and features of gene structure variation, etc, for theseveral components such as analyzing the molecule mechanism of the transgressive variation ofquantitative trait from filial generation and the new resarching module.The results show that:The variety with high contents of grain amylose has low content of protein and little taste.What is more, the Val max, Val min and the viscosity value of the RVA profile character is also little.But the viscosity reduction peak value and final viscosity will grow as the contents of amylosegrowing, and the variety with high contents of amylose shows the positive setback value, and thatwith low content is negative. In the variety with low contents of grain amylose, there is relativehigh content of protein, and the Val max, Val min and the viscosity value is also relatively high.With the grown of the contents of amylose, the grain weight per plant is raised, but the thousandkernel weight is on the contary, which means that it decline as the grown of the contents ofamylose.By the side of endosperm starch accumulation, in the two combinations, the trend is nearly thesame among the contect of different amylose and accumulation of endosperm starch, amylose andamylopection from parents and generations. The total content of starch is high if the content ofamylose of this type is also high. The speed of synthesis and accumulation of the endospermamylose depends on the hereditary factors. The contect of amylose, which is synthetized andaccumulated from the gene type with high content of amylose, is higher than that from gene type with low content of amylose. And endosperm amylopectin is synthetized and accumulated mainlyin the early and middle section of grouting, which is earlier than that of amylose.In this study, the amylase content which had significant difference in parents and hybridprogeny were used to analyze the characteristics of changes in the rbe gene relative expression, theaccumulated amylose content and enzymes activities during grain filling. The results showed thatthe accumulated amylose content and enzymes activities in parents and hybrid progeny with highamylose contents were significantly higher than the low. The amylose content were positivelycorrelated with enzymes activities during grain filling; the relative expression level of rbe1andrbe3activities increased to a peak and declined during grain filling with a single-peak curve. Theexpression peak appeared17d after heading. The expression of rbe4was relatively small.Analysed from accumulation of endosperm starch, there is positive correlation between theRBE activity in different moment of grouting and contect of amylose, total contect of starch in suchmoment. There is also strong positive correlation between Endosperm amylose and the mRNAexpression quantity of rbe1and rbe3, but negative correlation with mRNA expression quantity ofrbe4. The correlation is the same with endosperm starch branching enzyme. It means that the genetype of mRNA expression quantity ofrbe1and rbe3is high, which has high content of amyloseand positive activity of starch branching enzyme. The low content type has low expression quantity.The expression quantity ofrbe4is on the contrary.The length of the complete cloned rbe1genome sequence is2463bp in this expeirment, with820amino acid residue coded. Compared with nucleotide sequence published in GenBank, thehomology of the parents and generations is99.96%,99.59%,99.80%,99.88%in thecombination.There are two differeces in amino acids between high offspring H6and high parentH4, and four differences between low offspring L12and low parent L11. Although there is highhomology in the rbe1gene coding base sequence between the variety with different contect ofendosperm amylose, and amino acid sequence is stongly conservative, during the process of geneseparation and stabilization of the filial generation, there are still changes of base and amino acid onsome indicidual nucleotide sites, which is the fundmental of the heritable variation for the offspring.