Effects of the activities of key enzymes involved in starch biosynthesis on the fine structure of amylopectin in developing rice (Oryza sativa L.) endosperms
Effects of the activities of key enzymes involved in starch biosynthesis on the fine structure of amylopectin in developing rice (Oryza sativa L.) endosperms
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DOI：
10.1007/s11427-008-0120-y
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发表时间：
2008-10-01
期刊：
影响因子：
--
通讯作者：
Liang JianSheng
中科院分区：
文献类型：
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作者：
Lue Bing;Guo ZhiGang;Liang JianSheng
以转反蜡基因水稻植株为材料，研究了淀粉合成相关酶AGPase、SSS、SBE和DBE活性的动态变化，并用异淀粉酶处理表征了水稻籽粒发育过程中支链淀粉超微结构的变化。并分析了这些关键酶活性之间的关系。转基因皖粳9522对直链淀粉合成有明显的抑制作用，但对总淀粉含量和最终粒重的影响较小。对淀粉生物合成相关酶活性变化的分析表明，不同的酶活性在水稻胚乳发育过程中表达不同。可溶性淀粉合成酶在胚乳发育早期表达较高，而颗粒结合淀粉合成酶(GBSS)在胚乳发育中期表达最强。除DBE外，两个水稻品种间AGPase和SBE活性变化无明显差异。支链淀粉的分布格局在水稻籽粒发育过程中不断变化，且在两个水稻品种间存在差异。结果表明，支链淀粉的合成先于直链淀粉的合成，不同的酶在支链淀粉的合成中起着不同的作用。
The dynamic changes of the activities of enzymes involving in starch biosynthesis, including ADP-glucose pyrophosphorylase (AGPase), soluble starch synthases (SSS), starch branching enzyme (SBE) and starch debranching enzymes (DBE) were studied, and changes of fine structure of amylopectin were characterized by isoamylase treatment during rice grain development, using trans anti-waxy gene rice plants. The relationships between the activities of those key enzymes were also analyzed. The amylose synthesis was significantly inhibited in transgenic Wanjing 9522, but the total starch content and final grain weight were less affected as compared with those of non-transgenic Wanjing 9522 rice cultivar. Analyses on the changes of activities of enzymes involving in starch biosynthesis showed that different enzyme activities were expressed differently during rice endosperm development. Soluble starch synthase is relatively highly expressed in earlier stage of endosperm development, whilst maximal expression of granule-bound starch synthase (GBSS) occurred in mid-stage of endosperm development. No obvious differences in changes of the activities of AGPase and SBE between two rice cultivars investigated, except the DBEs. Distribution patterns of branches of amylopectin changed continually during the development of rice grains and varied between two rice cultivars. It was suggested that amylopectin synthesis be prior to the synthesis of amylose and different enzymes have different roles in controlling syntheses of branches of amylopectin.