Suppression of starch synthesis in rice stems splays tiller angle due to gravitropic insensitivity but does not affect yield
Suppression of starch synthesis in rice stems splays tiller angle due to gravitropic insensitivity but does not affect yield
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DOI：
10.1071/fp14159
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发表时间：
2015-01-01
影响因子：
3
通讯作者：
Aoki, Naohiro
中科院分区：
文献类型：
--
作者：
Okamura, Masaki;Hirose, Tatsuro;Aoki, Naohiro
在水稻（Oryza sativa L.）中，分蘖角度（定义为主茎与其侧分蘖之间的角度）是涉及光利用效率的重要因素之一。为了阐明分蘖角、向重力性与茎淀粉积累之间的关系，我们研究了一个低茎淀粉水稻突变体的茎部向重力性反应，该突变体缺乏ADP-葡萄糖焦磷酸化酶（AGP）大亚基，称为OsAGPL 1，并表现出相对分散的分蘖角。该突变体表现出的不敏感的向重力性反应使我们得出这样的结论：茎淀粉减少引起的向重力性不敏感的分蘖角张开。此外，由于另一个AGP基因OsAGPL 3在重力反应位点以相当高的水平表达，我们产生了一个缺乏OsAGPL 1和OsAGPL 3的双突变体。与单突变体相比，双突变体的茎淀粉含量更低，向地性反应更不敏感，分蘖角度扩展更大。这表明，淀粉水平降低引起的分蘖角的扩大根据降低的程度而强烈。我们发现，在干物质生产方面，双突变体和野生型植物之间没有显着差异。这些结果为茎淀粉积累和理想植株构型的重要性提供了新的见解。
In rice (Oryza sativa L.), tiller angle - defined as the angle between the main culm and its side tillers - is one of the important factors involved in light use efficiency. To clarify the relationship between tiller angle, gravitropism and stem-starch accumulation, we investigated the shoot gravitropic response of a low stem-starch rice mutant which lacks a large subunit of ADP-glucose pyrophosphorylase (AGP), called OsAGPL1 and exhibits relatively spread tiller angle. The insensitive gravitropic response exhibited by the mutant led us to the conclusion that insensitivity of gravitropism caused by stem-starch reduction splayed the tiller angle. Furthermore, since another AGP gene called OsAGPL3 was expressed at considerable levels in graviresponding sites, we generated a double mutant lacking both OsAGPL1 and OsAGPL3. The double mutant exhibited still lower stem-starch content, less sensitive gravitropic response and greater tiller angle spread than the single mutants. This indicated that the expansion of the tiller angle caused by the reduction in starch level was intense according to the extent of the reduction. We found there were no significant differences between the double mutant and wild-type plants in terms of dry matter production. These results provided new insight into the importance of stem-starch accumulation and ideal plant architecture.