Cell Walls of Developing Wheat Starchy Endosperm: Comparison of Composition and RNA-Seq Transcriptome
Cell Walls of Developing Wheat Starchy Endosperm: Comparison of Composition and RNA-Seq Transcriptome
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DOI：
10.1104/pp.111.189191
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发表时间：
2012-02-01
期刊：
影响因子：
7.4
通讯作者：
Mitchell, Rowan A. C.
中科院分区：
文献类型：
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作者：
Pellny, Till K.;Lovegrove, Alison;Mitchell, Rowan A. C.
使用在籽粒灌浆期间的五个阶段分离的RNA-Seq确定六倍体小麦（Triticum aestivum）的发育中的淀粉质胚乳的转录组。该资源代表了鉴定负责淀粉质胚乳细胞壁的候选基因的极好方式，淀粉质胚乳细胞壁由阿拉伯木聚糖（AX）主导，占细胞壁多糖的70%，具有20%（1，3; 1，4）-β-D-葡聚糖、7%葡甘露聚糖和4%纤维素。与细胞壁相关的124个糖基转移酶（GT）和72个糖基水解酶（GH）基因的转录本的完整清单。最高表达的GT转录物（不包括已知参与淀粉合成的那些）是与参与木聚糖延伸的拟南芥（Arabidopsis thaliana）IRX 10相似的GT 47家族转录物，并且第二丰富的是GT 61。GT 43 IRX 9和IRX 14推定直向同源物的图谱与AX合成中的作用一致。低丰度被发现的转录物中的酰基辅酶A转移酶BAHD家族，其中的作用AX阿魏酰化已被假定。与淀粉胚乳相比，这些的相对表达量在整个谷粒中要大得多，与结合阿魏酸的水平相关。与胼胝质（GSL）、纤维素（CESA）、果胶（GAUT）和葡甘露聚糖（CSLA）合成相关的转录物在淀粉质胚乳中也是丰富的，而相应的细胞壁多糖在这些样品中被确认为低丰度（葡甘露聚糖和胼胝质）或不可检测的（果胶）。与这些多糖的水解相关的GH家族的丰富的成绩单也存在，这表明它们可以迅速翻转。GT31家族中丰富的转录物可能是将Gal残基添加到阿拉伯半乳聚糖肽的原因。
The transcriptome of the developing starchy endosperm of hexaploid wheat (Triticum aestivum) was determined using RNA-Seq isolated at five stages during grain fill. This resource represents an excellent way to identify candidate genes responsible for the starchy endosperm cell wall, which is dominated by arabinoxylan (AX), accounting for 70% of the cell wall polysaccharides, with 20% (1,3; 1,4)-beta-D-glucan, 7% glucomannan, and 4% cellulose. A complete inventory of transcripts of 124 glycosyltransferase (GT) and 72 glycosylhydrolase (GH) genes associated with cell walls is presented. The most highly expressed GT transcript (excluding those known to be involved in starch synthesis) was a GT47 family transcript similar to Arabidopsis (Arabidopsis thaliana) IRX10 involved in xylan extension, and the second most abundant was a GT61. Profiles for GT43 IRX9 and IRX14 putative orthologs were consistent with roles in AX synthesis. Low abundances were found for transcripts from genes in the acyl-coA transferase BAHD family, for which a role in AX feruloylation has been postulated. The relative expression of these was much greater in whole grain compared with starchy endosperm, correlating with the levels of bound ferulate. Transcripts associated with callose (GSL), cellulose (CESA), pectin (GAUT), and glucomannan (CSLA) synthesis were also abundant in starchy endosperm, while the corresponding cell wall polysaccharides were confirmed as low abundance (glucomannan and callose) or undetectable (pectin) in these samples. Abundant transcripts from GH families associated with the hydrolysis of these polysaccharides were also present, suggesting that they may be rapidly turned over. Abundant transcripts in the GT31 family may be responsible for the addition of Gal residues to arabinogalactan peptide.