Prior secondary cell wall formation is required for gelatinous layer deposition and posture control in gravi‐stimulated aspen
Prior secondary cell wall formation is required for gelatinous layer deposition and posture control in gravi‐stimulated aspen
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重力刺激白杨中的凝胶层沉积和姿势控制需要预先形成次生细胞壁
DOI：
10.1111/tpj.15466
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Taniguchi Toru
中科院分区：
文献类型：
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作者：
Takata Naoki;Tsuyama Taku;Nagano Soichiro;Baba Kei'ichi;Yasuda Yuko;Sakamoto Shingo;Mitsuda Nobutaka;Taniguchi Toru
细胞壁，特别是次生细胞壁（SCW），保持细胞形状和加强木材，但它们的结构和形状可以响应重力而改变。在硬木树中，张力木材沿着弯曲茎的上侧形成，并且包含在SCW内具有凝胶层（G‐层）的木材纤维细胞。在先前的研究中，我们产生了dnst/snd四重敲除的白杨（美洲杨×美洲杨），其中99%的木材纤维细胞的SCW形成受损。在本研究中，我们生产了nst/snd三重敲除白杨，其中大量的木纤维具有比野生型（WT）更细的SCW，并且一些没有SCW。由于SCW层总是在G层沉积之前形成，thenst/sndmutants提出了有趣的问题，即突变体是否可以在没有SCW的情况下形成G层，以及它们是否可以控制自己的姿态以应对重力方向的变化。Thenst/sndmutants和野生型植株在斜面上生长时表现出生长偏心率和导管频率降低，但三重突变体仅略微恢复其直立生长，而四重突变体无法保持其姿势。突变体清楚地表明，G层在含有SCW的木材纤维中形成，但在缺乏SCW的木材纤维中不形成。我们的研究结果表明，SCW是必不可少的G层的形成和姿态控制。此外，每个木材纤维细胞可能能够识别其细胞壁发育阶段，以启动G层的形成作为对重力刺激的响应。
Cell walls, especially secondary cell walls (SCWs), maintain cell shape and reinforce wood, but their structure and shape can be altered in response to gravity. In hardwood trees, tension wood is formed along the upper side of a bending stem and contains wood fiber cells that have a gelatinous layer (G‐layer) inside the SCW. In a previous study, we generatednst/sndquadruple‐knockout aspens (Populus tremula × Populus tremuloides), in which SCW formation was impaired in 99% of the wood fiber cells. In the present study, we producednst/sndtriple‐knockout aspens, in which a large number of wood fibers had thinner SCWs than the wild type (WT) and some had no SCW. Because SCW layers are always formed prior to G‐layer deposition, thenst/sndmutants raise interesting questions of whether the mutants can form G‐layers without SCW and whether they can control their postures in response to changes in gravitational direction. Thenst/sndmutants and the WT plants showed growth eccentricity and vessel frequency reduction when grown on an incline, but the triple mutants recovered their upright growth only slightly, and the quadruple mutants were unable to maintain their postures. The mutants clearly showed that the G‐layers were formed in SCW‐containing wood fibers but not in those lacking the SCW. Our results indicate that SCWs are essential for G‐layer formation and posture control. Furthermore, each wood fiber cell may be able to recognize its cell wall developmental stage to initiate the formation of the G‐layer as a response to gravistimulation.