Moderate drought alleviates the damage to grain quality at high temperatures by improving the starch synthesis of inferior grains in japonica rice

Abstract

In agricultural production, temperature and moisture are important factors affecting grain yield and quality. Although moderate drought at the grain filling stage can effectively alleviate the damage caused by high temperature, the specific regulatory mechanism of moderate drought at the high temperature on starch synthesis is still unclear. To explore the effects and mechanisms of high temperature and moderate drought on rice starch synthesis at the grain filling stage, enzyme activities and gene expression levels involved in starch synthesis under four different treatments were investigated in this study. The starch synthesis of a japonica inbred rice under four treatments (CK, HT, WS, HT+WS) during the grain filling was discussed. The result shows that the effects of high temperature and moderate drought on grain filling mainly occur in the inferior grains of rice; through regulation of enzyme activities involved in starch synthesis and its main gene expression levels, the synthesis of rice starch can be affected. Therefore, the high temperature and moderate drought antagonized and moderate drought can alleviate the damage of high temperature to grain quality by improving the starch synthesis of inferior grain in japonica rice. This study provides a basis for stress-resistance cultivation and breeding strategies of rice with high temperature tolerance.1

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