Analysis On The Dynamic Changes Of The Starch Accumulations,Corresponding Enzyme Activities And Gene Expressions Between Two Maize Inbred Lines With Different Starch Contents

Starch is the main component of plant seeds.The process of grain weight is mainly the process of starch synthesis and accumulation.Starch is the most abundant storage carbohydrate in plants. It was quite important viewed its use in food, feed and industry. In order to know more about the starch synthesis in maize storage organ, we carried our study. Starch in maize kernels was firstly carefully measured two derived lines of the Huangzaosi. They are Qi-310and Jing-24.The two inbred lines with the highest and lowest starch contents among these derived lines were chosen for our study. The dynamic changes of total starch accumulation, corresponding enzyme activities and gene expressions during the development of maize kernels were analyzed between the two inbred lines. Results indicated that:1.Starch content of Qi-310is76.87%.Starch content of Jing-24is63.73%.The starch accumulation were measured during grouting.The result showed that starch accumulating rate of Qi-310were higher than Jing-24during grouting.2.A11enzymes including AGPase, SS, SBE and DBE had the enzyme activity, but the enzymes in Qi-310(highest starch) were cooperated with each other stronger than Jing-24(lowest starch).3.We chosed15starch synthesis genes which mainly express in the maize endosperm.Though some starch synthesis genes showed different expression pattern, most starch synthesis genes had higher expression during the middle development of maize kernels. All genes showed higher expression pattern in Qi-310than in Jing-24at most time.Sometimes, synthesis genes in Qi-310showed higher expression.For examp, GBSSâ…¡b expressed in20days after pollination and ISO2in10days after pollination.4.Cooperation of starch synthesis in Qi-310was more closly than in Jing-24. The result also showed a significant correlation between some enzymes.Co-expression of the starch synthesis genes could be clearly observed in Qi-310compared to Jing-24. All our results indicated that co-expression of starch synthesis genes might play an important role in higher storage starch in maize kernels.