| Maize play an important role on agricultural production both in China and the world as it is the main feed, foodstuffs and industrial materials. Amylolytic enzymes exist in almost every plant and have better activity in the seed of cereal after germination. Enzyme is the one of physiologically active substances during the germination of seed and has a very obvious change of enzyme activity. Maize starch was degraded and small molecules of sugar content increased under thhe effect that enzymes break down starch. At present, research about amylolytic enzymes in maize focused on seeds, seed physiology, improvement of starch quality, production of industrial enzyme pharmaceutical preparation via the enzyme effect of maize itself and a series of physiological changes,but rarely reported about the regularity of the activity of enzymes decompose starch (a-amylase,β-amylase, starch phosphorylase and debranching enzyme) in seed germination and the temporal and spatial gene express.The four inbred lines of maize--huangzaosi,Mo 17,08-641,18-599--are the object of this study. By measuring the enzyme activity performance of their seed germination to study the activity performance regularity of the four amylolytic enzyme, combined with the rate of seed germination rate and agronomy character performance during the germination, selected 08-641 with high starch content as the field test materials. Use the technology of RT-PCR, to study the regularity of starch decomposition enzymes's activity dynamic expression and the temporal and spatial expression of its eight genes[a-amylase,β-amylase,β-amylase (amy5), DBE (zpul),DBE(iso2), DBE(iso3), Sp(1precursor) and Sp(2precursor)] of the seeds and leaves after pollination,to provide foundation for the useing biotechnology in breed, accelerating breed speed,modifing gene and improving yield and quality of maize starch.The major findings are summarized as follows:1. starch decomposition enzyme activity in four inbred lines germination 3 days 4 days maximum, then slowly lower to maintain stability.08-641 of a-amylase activity and DBE activity was significantly lower than the other three inbred lines, and the peak activity of phosphorylated starch a-amylase activity than the peak one day later, while the other two enzymes are inbred peak the same day, P-amylase and other inbred lines were not significantly different. This may be 08-641 of germination of the reasons for weak growth. 08-641 in 10 to 20 days after pollination, leaves and grains of starch phosphorylase activity increased gradually, through the activity associated with the accumulation of starch found in the vitality of starch phosphorylase in starch accumulation in the same positive correlation. Description corn starch phosphorylase is filling one of the factors of enrichment. P-amylase, a-amylase, DBE activity is changing from high to low, which may be established after pollination, the library needs to provide the energy for decomposition of starch.2. Quantitative PCR data revealed:(1) Grain and leaf type expression of early gene (13-20DAP):a-amylase,β-amy2,β-amy5,SP1p,DBE(iso2) and DBE(iso3).(2) Grain and leaf type expression of late genes (20-30DAP):DBE (ZPUL) and SP2p.(3) Gene expression only in the grain:β-amy5 and SP1p; (4) SP2p dynamic gene expression and starch accumulation dynamics were significantly correlated. SP2p gene may be mainly involved in starch synthesis. |
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