Regulation Gene Expression in the Remobilization of Carbon Reserves in Rice Stems During Grain Filling
Regulation Gene Expression in the Remobilization of Carbon Reserves in Rice Stems During Grain Filling
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灌浆期水稻茎碳储量再利用的调控基因表达
DOI：
10.1093/pcp/pcx072
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发表时间：
2017-08-01
影响因子：
4.9
通讯作者：
Zhang, Jian-Hua
中科院分区：
文献类型：
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作者：
Wang, Guan-Qun;Hao, Shuai-Shuai;Zhang, Jian-Hua
开花前水稻秸秆（茎和鞘）中的碳储备对籽粒灌浆有重要贡献。然而，碳储备从秸秆向籽粒再动员的分子机制仍不清楚。在本研究中，超级稻两优培九和常规稻9311表现出不同的碳储备再动员行为。在籽粒灌浆的三个阶段对两优培九和9311秸秆的转录组图谱进行了分析。在差异表达基因（DGs）中，与开花后10天的681个和20天的495个相比，两优培九和9311在开花后30天有5733个基因独特地上调或下调，这表明在籽粒灌浆后期两优培九的基因表达图谱与9311有很大差异。差异表达基因的京都基因与基因组百科全书（KEGG）分析和基因本体论（GO）分类均表明，碳水化合物分解代谢途径、植物激素信号转导和光合作用途径在差异表达基因中富集，这表明它们在碳储备再动员中的作用，在一定程度上解释了两个品种在籽粒灌浆期间非结构性碳水化合物含量、光合作用和脱落酸（ABA）含量的差异。通过实时定量PCR和酶活性测定进一步比较分析和验证表明，参与海藻糖合成（海藻糖 - 磷酸磷酸酶和海藻糖6 - 磷酸合酶/磷酸酶）、淀粉降解（β - 淀粉酶）和蔗糖合成（蔗糖 - 磷酸合酶和蔗糖合酶）的基因对碳储备再动员很重要，而ABA含量由NCED1和ABA8ox1基因的相互作用决定。9311中所有这些基因的较高表达水平以及ABA含量导致9311的碳储备再动员效率高于两优培九。
Carbon reserves in rice straw (stem and sheath) before flowering contribute to a significant portion of grain filling. However, the molecular mechanism of carbon reserve remobilization from straw to grains remains unclear. In this study, super rice LYP9 and conventional rice 9311 showed different carbon reserve remobilization behaviors. The transcriptomic profiles of straws of LYP9 and 9311 were analyzed at three stages of grain filling. Among the differentially expressed genes (DGs), 5,733 genes were uniquely up-or down-regulated at 30 days after anthesis (DAA) between LYP9 and 9311 in comparison with 681 at 10 DAA and 495 at 20 DAA, suggesting that the gene expression profile of LYP9 was very different from that of 9311 at the late stage of grain filling. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and Gene Ontology (GO) classification of DGs both showed that the carbohydrate catabolic pathway, plant hormone signal transduction and photosynthesis pathway were enriched in DGs, suggesting their roles in carbon reserve remobilization, which explains to a certain extent the difference in non-structural carbohydrate content, photosynthesis and ABA content between the two cultivars during grain filling. Further comparative analysis and confirmation by quantitative real-time PCR and enzyme assays suggest that genes involved in trehalose synthesis (trehalose- phosphate phosphatase and trehalose 6-phosphate synthase/phosphatase), starch degradation (beta-amylase) and sucrose synthesis (sucrose-phosphate synthase and sucrose synthase) were important for carbon reserve remobilization, whereas ABA content was determined by the counteraction of NCED1 and ABA8ox1 genes. The higher expression level of all these genes and ABA content in 9311 resulted in better efficiency of carbon reserve remobilization in 9311 than in LYP9.