Impaired Cellulose Synthase Guidance Leads to Stem Torsion and Twists Phyllotactic Patterns in Arabidopsis
Impaired Cellulose Synthase Guidance Leads to Stem Torsion and Twists Phyllotactic Patterns in Arabidopsis
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DOI：
10.1016/j.cub.2013.04.013
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发表时间：
2013-05-20
期刊：
影响因子：
9.2
通讯作者：
Hamant, Olivier
中科院分区：
文献类型：
--
作者：
Landrein, Benoit;Lathe, Rahul;Hamant, Olivier
植物细胞壁中刚性纤维素微纤丝的平行排列介导各向异性生长[1，2]。这在很大程度上由皮质微管控制，皮质微管驱动纤维素合成酶（CESA）复合物在质膜上的插入[3，4]和轨迹[5-7]。CESA相互作用蛋白1（CSI 1）作为CESA和皮质微管之间的物理连接物[8-10]。在这里，我们表明，csi 1突变体的花序茎表现出微妙的右手扭转。由于纤维素沉积在很大程度上是从皮质微管csi 1解偶联，我们假设，严格横向沉积的微纤维在野生型被取代的螺旋方向的统一手性的突变体和螺旋微纤维排列产生扭转。有趣的是，膨胀细胞的弹性和粘性模型都预测微纤维的净螺旋取向会产生扭矩[11，12]。我们确实在csi 1细胞中观察到了倾斜的微纤维，在纤维素合成受损的csi 1 prc 1背景中几乎不存在扭转。此外，茎扭转导致了csi 1突变体中一种新的双峰和稳健的叶序模式，说明了生长扰动如何用一种不同的、同样稳健的模式取代一种稳健的数学模式。
The parallel alignment of stiff cellulose microfibrils in plant-cell walls mediates anisotropic growth [1, 2]. This is largely controlled by cortical microtubules, which drive the insertion [3, 4] and trajectory of the cellulose synthase (CESA) complex at the plasma membrane [5-7]. The CESA interactive protein 1 (CSI1) acts as a physical linker between CESA and cortical microtubules [8-10]. Here we show that the inflorescence stems of csi1 mutants exhibit subtle right-handed torsion. Because cellulose deposition is largely uncoupled from cortical microtubules in csi1, we hypothesize that strictly transverse deposition of microfibrils in the wild-type is replaced by a helical orientation of uniform handedness in the mutant and that the helical microfibril alignment generates torsion. Interestingly, both elastic and viscous models for an expanding cell predict that a net helical orientation of microfibrils gives rise to a torque [11, 12]. We indeed observed tilted microfibrils in csi1 cells, and the torsion was almost absent in a csi1 prc1 background with impaired cellulose synthesis. In addition, the stem torsion led to a novel bimodal and robust phyllotactic pattern in the csi1 mutant, illustrating how growth perturbations can replace one robust mathematical pattern with a different, equally robust pattern.