Effect of sucrose on activity of starch synthesis enzymes in rice ears in culture
Effect of sucrose on activity of starch synthesis enzymes in rice ears in culture
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DOI：
10.1111/j.1399-3054.2005.00520.x
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发表时间：
2005-07-01
影响因子：
6.4
通讯作者：
Ohsugi, R
中科院分区：
文献类型：
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作者：
Sasaki, H;Edo, E;Ohsugi, R
水稻籽粒灌浆过程淀粉合成不仅受源器官碳水化合物供应的影响，而且还受库活性的影响，包括与淀粉合成有关的酶的活性。为了研究易位碳水化合物对库活性的影响，我们培养了分离的耳朵（开花后7天切）在含有各种浓度的蔗糖，谷氨酰胺和维生素的溶液中。穗培养开始后16天的粒重随着蔗糖浓度的增加而增加，直到50-70 g蔗糖l（-1），但不超过这个范围，可能是因为低水势。ADP葡萄糖焦磷酸化酶、可溶性淀粉合成酶和蔗糖合成酶的活性在无蔗糖条件下迅速下降，但随着蔗糖浓度的增加而增加，直至50-70 g l（-1）。这些酶和蔗糖转运蛋白的mRNA表达也普遍增加蔗糖在50-70克升（-1）。蔗糖合成酶的活性与mRNA表达量相关性较好，而其它酶活性与mRNA表达量相关性不好。因此，我们认为，水稻穗粒库的活性，从而灌浆，是由源器官的碳水化合物供应的影响，这也是由于转录调控以外的因素。
Grain filling of rice (Oryza sativa L.) is thought to be affected not only by the supply of carbohydrate from source organs, but also by sink activity, including the activities of enzymes related in starch synthesis. To examine the effect of translocated carbohydrate on sink activity, we cultured detached ears (cut 7 days after flowering) in a solution containing sucrose at various concentrations, glutamine and vitamins. Grain weights 16 days after the start of ear culture increased with increasing sucrose concentration up to 50-70 g sucrose l(-1), but not above this range, probably because of low water potential. Activities of ADP glucose pyrophosphorylase, soluble starch synthase and sucrose synthase rapidly decreased in grains grown without sucrose, but increased with increasing sucrose concentration up to 50-70 g l(-1). Expression of mRNAs for these enzymes and for sucrose transporter was also generally increased by sucrose at 50-70 g l(-1). Though there was a good correlation between activity and expression of mRNA for sucrose synthase, the correlation for other enzymes was not very good. Thus, we suggested that the sink activity of grains in rice ears, and therefore the grain filling, was affected by the supply of carbohydrate from source organs, and that it was also owing to factors other than transcriptional regulation.