G-fibre cell wall development in willow stems during tension wood induction.
G-fibre cell wall development in willow stems during tension wood induction.
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DOI：
10.1093/jxb/erv358
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发表时间：
2015-10
影响因子：
6.9
通讯作者：
Karp A
中科院分区：
文献类型：
--
作者：
Gritsch C;Wan Y;Mitchell RA;Shewry PR;Hanley SJ;Karp A
杨柳抗拉材凝胶纤维中细胞壁多糖的免疫组织化学定位表明，（1-4）-β-D-半乳聚糖在G-层中有明显的分布。柳树（柳属）是生物能源和生物燃料的重要潜在原料。以前的工作表明，反应木材（RW）的形成可能是一个理想的性状，生物燃料生产的柳树，因为它是与葡萄糖产量增加，但杨柳RW还没有表征细胞壁成分。Fasciclin-like arabinogalactan（弗拉）蛋白在杨树RW中表达上调，参与细胞粘附和纤维素生物合成。COBRA基因通过调节纤维素微纤维沉积的方向参与各向异性细胞扩增。本研究确定了时间和空间沉积的非纤维素多糖的细胞壁的张力木材（TW）的组成部分杨柳RW，并比较它与对生木材（OW）和正常木材（NW）使用特异性抗体和共聚焦激光扫描显微镜和透射电子显微镜。此外，使用RNA原位杂交比较弗拉基因（SxFLA 12）和COBRA-like基因（SxCOBL 4）的表达模式。发现非纤维素多糖（1-4）-β-D-半乳聚糖、甘露聚糖和去酯化同型半乳糖醛酸聚糖的沉积与TW高度相关，通常与G层本身相关。特别令人感兴趣的是，G-层本身可以高度富集（1-4）-β-D-半乳聚糖，特别是在G-层仍然增厚的G-纤维中，这与先前在白杨中的研究形成对比。只有木聚糖表现出类似的分布在TW，OW和NW，被限制在次生细胞壁层。SxFLA 12和SxCOBL 4转录本在发育TW中特异性表达，证实了它们的重要性。本文提出了杨柳G纤维细胞发育过程中多糖分布的模型。
Immunolocalization of cell wall polysaccharides in gelatinous fibres of willow tension wood indicates a distinct distribution with a particular enrichment of (1–4)-β-D-galactan in the G-layer. Willows (Salix spp.) are important as a potential feedstock for bioenergy and biofuels. Previous work suggested that reaction wood (RW) formation could be a desirable trait for biofuel production in willows as it is associated with increased glucose yields, but willow RW has not been characterized for cell wall components. Fasciclin-like arabinogalactan (FLA) proteins are highly up-regulated in RW of poplars and are considered to be involved in cell adhesion and cellulose biosynthesis. COBRA genes are involved in anisotropic cell expansion by modulating the orientation of cellulose microfibril deposition. This study determined the temporal and spatial deposition of non-cellulosic polysaccharides in cell walls of the tension wood (TW) component of willow RW and compared it with opposite wood (OW) and normal wood (NW) using specific antibodies and confocal laser scanning microscopy and transmission electron microscopy. In addition, the expression patterns of an FLA gene (SxFLA12) and a COBRA-like gene (SxCOBL4) were compared using RNA in situ hybridization. Deposition of the non-cellulosic polysaccharides (1–4)-β-D-galactan, mannan and de-esterified homogalacturonan was found to be highly associated with TW, often with the G-layer itself. Of particular interest was that the G-layer itself can be highly enriched in (1–4)-β-D-galactan, especially in G-fibres where the G-layer is still thickening, which contrasts with previous studies in poplar. Only xylan showed a similar distribution in TW, OW, and NW, being restricted to the secondary cell wall layers. SxFLA12 and SxCOBL4 transcripts were specifically expressed in developing TW, confirming their importance. A model of polysaccharides distribution in developing willow G-fibre cells is presented.