Transcriptome profiling of radiata pine branches reveals new insights into reaction wood formation with implications in plant gravitropism.
Transcriptome profiling of radiata pine branches reveals new insights into reaction wood formation with implications in plant gravitropism.
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DOI：
10.1186/1471-2164-14-768
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发表时间：
2013-11-08
期刊：
影响因子：
4.4
通讯作者：
Wu HX
中科院分区：
文献类型：
--
作者：
Li X;Yang X;Wu HX
在树枝和弯曲树干上形成压缩木和对生木是针叶树对各种位移力（如重力、风、雪和人工弯曲）的适应性特征。先前的一些研究已经对人工或自然弯曲的针叶树树干的管状体、木材和基因转录进行了研究。这些研究为木材在弯曲力和重力刺激下的反应形成提供了分子基础。然而，对重力胁迫下针叶树枝的反应材形成和基因转录的研究却知之甚少。本研究利用SilviScan®技术对辐射松（Pinus radiata D. Don）枝条的管胞和木材性状进行了表征，并利用cDNA微阵列技术对辐射松枝条中CW和OW基因的差异转录进行了研究。连续灌丛在管胞和木材性状上与普通灌丛有显著差异，生长加快，管胞壁增厚，微纤维角（MFA）增大，密度增大，刚度降低。然而，在径向和切向上，CW和OW管胞直径相似。因此，重力应力对木材生长、次生壁沉积、纤维素微纤维取向和木材性能影响较大，但对原生壁膨胀影响较小。基因芯片转录结果显示，春、秋两季，CW和OW木质部约29%的转录组发生了显著改变，为管胞和木材性状的剧烈变化提供了分子证据。与细胞分裂、纤维素生物合成、木质素沉积和微管相关的基因在CW中大多上调，从而使其生长更快、管胞壁更厚、密度更高、MFA更大、硬度更低。然而，在CW和OW中，参与细胞扩增和初代管壁形成的基因的转录量不同，这表明它们的管胞壁直径相似，管胞长度不同。有趣的是，许多与激素和钙信号以及各种环境胁迫相关的基因在CW中都被上调，这为重力刺激下反应木材形成的早期分子特征提供了重要线索。首次全面研究了针叶树的管胞特征、木材特性和基因转录，为研究重力胁迫下木材的反应形成提供了更准确和新的见解。已鉴定的具有不同功能的差异转录基因导致或暗示了辐射松枝中CW和OW的剧烈变化。这些基因为进一步研究植物向地性反应成木的分子机制提供了极好的候选基因。本文的在线版本（doi:10.1186/1471-2164-14-768）包含补充材料，可供授权用户使用。
Formation of compression (CW) and opposite wood (OW) in branches and bent trunks is an adaptive feature of conifer trees in response to various displacement forces, such as gravity, wind, snow and artificial bending. Several previous studies have characterized tracheids, wood and gene transcription in artificially or naturally bent conifer trunks. These studies have provided molecular basis of reaction wood formation in response to bending forces and gravity stimulus. However, little is known about reaction wood formation and gene transcription in conifer branches under gravity stress. In this study SilviScan® technology was used to characterize tracheid and wood traits in radiate pine (Pinus radiata D. Don) branches and genes differentially transcribed in CW and OW were investigated using cDNA microarrays. CW drastically differed from OW in tracheids and wood traits with increased growth, thicker tracheid walls, larger microfibril angle (MFA), higher density and lower stiffness. However, CW and OW tracheids had similar diameters in either radial or tangential direction. Thus, gravity stress largely influenced wood growth, secondary wall deposition, cellulose microfibril orientation and wood properties, but had little impact on primary wall expansion. Microarray gene transcription revealed about 29% of the xylem transcriptomes were significantly altered in CW and OW sampled in both spring and autumn, providing molecular evidence for the drastic variation in tracheid and wood traits. Genes involved in cell division, cellulose biosynthesis, lignin deposition, and microtubules were mostly up-regulated in CW, conferring its greater growth, thicker tracheid walls, higher density, larger MFA and lower stiffness. However, genes with roles in cell expansion and primary wall formation were differentially transcribed in CW and OW, respectively, implicating their similar diameters of tracheid walls and different tracheid lengths. Interestingly, many genes related to hormone and calcium signalling as well as various environmental stresses were exclusively up-regulated in CW, providing important clues for earlier molecular signatures of reaction wood formation under gravity stimulus. The first comprehensive investigation of tracheid characteristics, wood properties and gene transcription in branches of a conifer species revealed more accurate and new insights into reaction wood formation in response to gravity stress. The identified differentially transcribed genes with diverse functions conferred or implicated drastic CW and OW variation observed in radiata pine branches. These genes are excellent candidates for further researches on the molecular mechanisms of reaction wood formation with a view to plant gravitropism. The online version of this article (doi:10.1186/1471-2164-14-768) contains supplementary material, which is available to authorized users.
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DOI：
10.1073/pnas.1011066108
发表时间：
2011-01-25
影响因子：
11.1
作者：
Kim, Keunhwa;Shin, Jieun;Choi, Giltsu
通讯作者：
Choi, Giltsu
DOI：
10.1073/pnas.0900188106
发表时间：
2009-08-04
影响因子：
11.1
作者：
Coleman, Heather D.;Yan, Jimmy;Mansfield, Shawn D.
通讯作者：
Mansfield, Shawn D.
影响因子：
4.3
作者：
Bhandari, Suchita;Fujino, Takeshi;Joshi, Chandrashekhar P.
通讯作者：
Joshi, Chandrashekhar P.
影响因子：
64.8
作者：
通讯作者：
--
影响因子：
5.8
作者：
Baldi, P;Long, AD
通讯作者：
Long, AD