A carbohydrate-binding protein, B-GRANULE CONTENT 1, influences starch granule size distribution in a dose-dependent manner in polyploid wheat
A carbohydrate-binding protein, B-GRANULE CONTENT 1, influences starch granule size distribution in a dose-dependent manner in polyploid wheat
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DOI：
10.1093/jxb/erz405
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发表时间：
2020-01-01
影响因子：
6.9
通讯作者：
Trafford, Kay
中科院分区：
文献类型：
--
作者：
Chia, Tansy;Chirico, Marcella;Trafford, Kay
在小麦族胚乳（例如小麦和大麦）中，淀粉颗粒具有双峰尺寸分布（具有A型和B型颗粒），而在其他禾本科植物中，胚乳含有具有单峰尺寸分布的淀粉颗粒。在这里，我们确定了基因，BGC 1（B-GRANULE CONTENT 1），负责山羊草和小麦中的B型淀粉粒含量。已知该基因的直向同源物影响二倍体如水稻、拟南芥和大麦中的淀粉合成。然而，使用多倍体小麦族物种，我们发现了一个更复杂的生物学作用BGC 1在淀粉粒启动：BGC 1抑制启动的A-颗粒在早期籽粒发育，但促进启动的B-颗粒在中期籽粒发育。我们提供的证据表明，BGC 1对淀粉合成的影响是剂量依赖性的，并表明，三个非常不同的淀粉表型的条件下，基因剂量的BGC 1在多倍体小麦：正常双峰淀粉颗粒形态; A-颗粒很少或没有B-颗粒;或多晶型淀粉很少正常的A-或B-颗粒。我们从这项工作中得出结论，BGC 1参与控制小麦族胚乳中B型淀粉颗粒的起始，并且它对颗粒大小和数量的精确影响因基因剂量和发育阶段而异。
In Triticeae endosperm (e.g. wheat and barley), starch granules have a bimodal size distribution (with A- and B-type granules) whereas in other grasses the endosperm contains starch granules with a unimodal size distribution. Here, we identify the gene, BGC1 (B-GRANULE CONTENT 1), responsible for B-type starch granule content in Aegilops and wheat. Orthologues of this gene are known to influence starch synthesis in diploids such as rice, Arabidopsis, and barley. However, using polyploid Triticeae species, we uncovered a more complex biological role for BGC1 in starch granule initiation: BGC1 represses the initiation of A-granules in early grain development but promotes the initiation of B-granules in mid grain development. We provide evidence that the influence of BGC1 on starch synthesis is dose dependent and show that three very different starch phenotypes are conditioned by the gene dose of BGC1 in polyploid wheat: normal bimodal starch granule morphology; A-granules with few or no B-granules; or polymorphous starch with few normal A- or B-granules. We conclude from this work that BGC1 participates in controlling B-type starch granule initiation in Triticeae endosperm and that its precise effect on granule size and number varies with gene dose and stage of development.