Study on the Accumulation laws of protein in Japonica rice seed during development

Abstract

Rice protein is nutritionally superior over most of the other food cereals in terms of amino acid composition. But rice is usually a low protein crop. So, it is important to investigate the change laws of protein for breeding rice with high protein content. The rice seed start to accumulate protein after flowering. In this study, Z601, a japonica rice variety, was used as the experimental material. Seeds of five days, ten days, fifteen days, twenty days, and twenty-five days after flowering (DAF) were collected. Protein contents were determined by Kjeldahl method in order to confirm the surge stage in rice seed. The components of rice protein at various development stages were analyzed by SDS-PAGE analysis to find the accumulation law of the individual protein components. The results showed that 15-20 DAF was the surge stage of protein accumulation in rice seed. The protein components in the seeds of 5 DAF did not include albumin and globulin and only contained glutenin and gliadin. After that stage albumin and globulin start to synthesis and the components of protein tended to be stable. The vast majority content of protein during rice seed development was glutenin with about 48 % of the total. The proportion of albumin to total protein content is 20 % and globulin is 15 %, also as gliadin. © Springer-Verlag Berlin Heidelberg 2014.