水稻稳定高垩白率突变体的获得与理化特性分析

稻米品质的形成是遗传因素和环境因素相互作用的结果,而环境因素对稻米品质的影响也是通过水稻的生理过程起作用的。本实验经过多年多点种植,从日本晴的T-DNA插入突变体库中筛选出6份稳定高垩白率的突变体材料。检测了可能影响淀粉的合成及淀粉体的精细结构,导致稻米亚垩白的产生和品质下降的蔗糖合酶、ADP-葡萄糖焦磷酸化酶(AGPase)、淀粉合酶、淀粉分支酶、淀粉去分支酶等酶活性的变化,试图从籽粒灌浆过程及淀粉合成途径中关键酶活性变化与成熟籽粒品质的相关性来解释垩白形成的机理。

Analysis of Physiological and Biochemical Characteristics of Six Mutants with Stable High Percentage of Chalkiness in Rice Grains

Chalkiness is an important quality character in rice, which is affected by comprehensive effects of genetic and environmental factors. Furthermore, the environmental factors affect the formation of chalkiness through the physiological and biochemical processes. Here, we screened six mutants with stable severe chalky rice grains from the T-DNA insertion mutant pool of cultivar Nipponbare. The changes in activities of the key enzymes associated with starch synthesis, including sucrose synthase, adenosine diphosphoglucose pyrophosphorylase (AGPase), starch synthase, starch branching enzyme and starch debranching enzyme in grains during the filling period, could impact the starch synthesis, the shape and fine structure of the starch granule, thus result in the formation of chalkiness. Temperature condition during grain filling is one of the most important environmental factors affecting the quality of rice. But high temperature stress did not take place during this experiment. To explain the mechanism of the formation of chalkiness from the physiological and biochemical aspects, we analyzed the fluctuation of the key enzyme activities associated with starch synthesis, sucrose content, starch content, and the ratio of amylose to total starch in mature grains. The results suggest that physiological studies of grain development are essential to reveal the formative mechanism of chalky rice.