Novel mutant alleles of the starch synthesis gene TaSSIVb-D result in the reduction of starch granule number per chloroplast in wheat.
Novel mutant alleles of the starch synthesis gene TaSSIVb-D result in the reduction of starch granule number per chloroplast in wheat.
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DOI：
10.1186/s12864-017-3724-4
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发表时间：
2017-05-08
期刊：
影响因子：
4.4
通讯作者：
Liu L
中科院分区：
文献类型：
--
作者：
Guo H;Liu Y;Li X;Yan Z;Xie Y;Xiong H;Zhao L;Gu J;Zhao S;Liu L
瞬时淀粉为植物生长提供碳和能量，其合成受一系列酶的共同作用调控。淀粉合成IV（SSIV）是重要的淀粉合酶亚型之一，但由于缺乏突变株系，其对小麦淀粉合成的影响尚未有报道。利用TILLING方法，我们在小麦基因TaSSIVb-D中鉴定出了54个突变，突变密度为1/165 Kb。其中，三种错义突变和一种无义突变预计会对蛋白质功能产生严重影响。在突变体中，TaSSIVb-D 显着下调，同源基因 TaSSIVb-A 和 TaSSIVb-B 没有补偿性增加。 TaSSIVb-D 表达的改变影响每个叶绿体的颗粒数量；与野生型相比，含0~2个颗粒的叶绿体数量明显增多，而含3~4个颗粒的叶绿体数量明显减少。光合作用受到相应影响；无义突变体在抽穗期的最大量子产率和PSII产率显着降低。这些结果表明，TaSSIVb-D 在小麦瞬时淀粉颗粒的形成中起着重要作用，进而影响光合作用的效率。本研究中创建的诱变群体可以有效鉴定目标基因的新等位基因，并可用作小麦功能基因组学的资源。本文的在线版本 (doi:10.1186/s12864-017-3724-4) 包含补充材料，可供授权用户使用。
Transient starch provides carbon and energy for plant growth, and its synthesis is regulated by the joint action of a series of enzymes. Starch synthesis IV (SSIV) is one of the important starch synthase isoforms, but its impact on wheat starch synthesis has not yet been reported due to the lack of mutant lines. Using the TILLING approach, we identified 54 mutations in the wheat gene TaSSIVb-D, with a mutation density of 1/165 Kb. Among these, three missense mutations and one nonsense mutation were predicted to have severe impacts on protein function. In the mutants, TaSSIVb-D was significantly down-regulated without compensatory increases in the homoeologous genes TaSSIVb-A and TaSSIVb-B. Altered expression of TaSSIVb-D affected granule number per chloroplast; compared with wild type, the number of chloroplasts containing 0–2 granules was significantly increased, while the number containing 3–4 granules was decreased. Photosynthesis was affected accordingly; the maximum quantum yield and yield of PSII were significantly reduced in the nonsense mutant at the heading stage. These results indicate that TaSSIVb-D plays an important role in the formation of transient starch granules in wheat, which in turn impact the efficiency of photosynthesis. The mutagenized population created in this study allows the efficient identification of novel alleles of target genes and could be used as a resource for wheat functional genomics. The online version of this article (doi:10.1186/s12864-017-3724-4) contains supplementary material, which is available to authorized users.