The phenotype of soluble starch synthase IV defective mutants of Arabidopsis thaliana suggests a novel function of elongation enzymes in the control of starch granule formation
The phenotype of soluble starch synthase IV defective mutants of Arabidopsis thaliana suggests a novel function of elongation enzymes in the control of starch granule formation
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DOI：
10.1111/j.1365-313x.2006.02968.x
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发表时间：
2007-02-01
期刊：
影响因子：
7.2
通讯作者：
Merida, Angel
中科院分区：
文献类型：
--
作者：
Roldan, Isaac;Wattebled, Fabrice;Merida, Angel
所有的植物和绿藻都是通过同样的五类延伸酶——淀粉合酶来合成淀粉的。拟南芥可溶性淀粉合成酶IV （SSIV）型延伸酶合成缺陷突变体现已被表征。突变植株表现出严重的生长缺陷，但仍积累了接近正常水平的多糖储存。详细的结构分析没有发现淀粉颗粒结构有任何变化。然而，每个质体的颗粒数量急剧减少，导致它们的大小大幅增加。这些结果将SSIV突变体与迄今为止报道的所有其他突变体区分开来，表明该酶类在控制颗粒数方面具有特定功能。因此，我们推测，SSIV可能选择性地参与淀粉颗粒形成的启动。
All plants and green algae synthesize starch through the action of the same five classes of elongation enzymes: the starch synthases. Arabidopsis mutants defective for the synthesis of the soluble starch synthase IV (SSIV) type of elongation enzyme have now been characterized. The mutant plants displayed a severe growth defect but nonetheless accumulated near to normal levels of polysaccharide storage. Detailed structural analysis has failed to yield any change in starch granule structure. However, the number of granules per plastid has dramatically decreased leading to a large increase in their size. These results, which distinguish the SSIV mutants from all other mutants reported to date, suggest a specific function of this enzyme class in the control of granule numbers. We speculate therefore that SSIV could be selectively involved in the priming of starch granule formation.