Analysis Of Starch Synthesis-related Gene Expression,Starch Granule Structure And Genetic Interaction Of Different Types Of Maize

Nowadays,maize starch has been widely used in food industry,medicine,agriculture and other fields,and maize starch occupies a large proportion in the starch market.Therefore,it is of great significance to study the gene expression pattern and granule structure in maize starch biosynthesis.The results of this study were as follows: real-time quantitative PCR(RT-q PCR),scanning electron microscope(SEM),laser diffraction particle size analyzer(LDPS),X-ray diffraction(XRD),attenuated total reflection Fourier transform infrared spectrometer(ATR-FTIR),hybridization and so on.1.The middle and late stage of grouting is the key period of amylose accumulation in high-amylose maize.The synthesis of amylose in waxy maize during early filling stage is of great significance to the accumulation of amylopectin.Starch granules(normal maize,waxy maize,popcorn)changed with the filling period from round ball type to irregular polygon,while high-amylose maize starch appeared "rod-like" granules from 25 DAP,and gradually became fine with the filling period.Starch size(normal maize,high-amylose maize,waxy maize and popcorn)increased gradually with the filling period,while the starch size of sweet maize decreased with the filling period.with the exception of high-amylose maize starch as B-type crystal,the other types of corn starch are A-type crystals.And the relative crystallinity of mazie starch decreased gradually with the filling stage,which may be caused by the increase of GBSS? gene expression.In these five types of maize starch,the change trend of near-program order degree is similar to that of relative crystallinity,and gradually decreases with the filling period.2.The high-amylose maize starch has higher amylose content and lower relative crystallinity than normal maize,probably due to the high expression of GBSS? and PUL genes and the low expression of SBE?a and SBE?b genes.The higher amylopectin content,relative crystallinity and particle size of waxy maize starch may be related to the high expression of SS?b?SBE??SBE?a and SBE?b genes in the middle and late stages of grouting.The changes in amylose content,relative crystallinity and near-range ordered structure of sweet maize starch may be controlled by GBSS? and SBE?b genes.The popcorn starch has lower relative crystallinity and near-range ordered structure than the common maize,which may be caused by the low expression of SS?? SS?a and SS?a genes in popcorn.3.The GBSS enzyme activity of high-amylose maize was significantly lower than that of normal maize,while SBE and DBE enzyme activities were significantly higher,which may be related to posttranscriptional modification.The correlation analysis found that the SBE of high-amylose maize was positively correlated with AGPase and SSS,and also with AGPase,indicating that amylose of high-amylose maize may be partly derived from the debranching of amylopectin.The hybridization experiments of gene interaction showed that the inbred lines of high-amylose maize in this study might be recessive mutants.