RNA-seq to identity genes expressed in dissected inflorescence meristems of Col-0 Arabidopsis thaliana plants.. RNA-seq to identity genes expressed in dissected inflorescence meristems of Col-0 Arabidopsis thaliana plants.

The shoot apical meristem of higher plants continuously generates new tissues and organs through complex changes in growth rates and directions of its individual cells. Cell growth, driven by turgor pressure, largely depends on the cell walls, which allow cell expansion through synthesis and structural changes. A previous study revealed a major contribution of wall isotropy in organ emergence, through the disorganization of cortical microtubules. We show here that this disorganization is coupled with the transcriptional control of genes involved in wall remodelling. Some of these genes are induced when microtubules are disorganized and cells shift to isotropic growth. Mechanical modelling shows that this coupling has the potential to compensate for reduced cell expansion rates induced by the shift to isotropic growth. Reciprocally, cell wall loosening induced by different treatments or altered cell wall composition promotes a disruption of microtubule alignment. Our data thus indicate the existence of a regulatory module activated during organ outgrowth, linking microtubule arrangements to cell wall remodelling. Overall design: 3 Col-0 samples

高等植物的茎尖分生组织（shoot apical meristem）可通过自身单个细胞生长速率与方向的复杂动态变化，持续产生新的组织与器官。细胞生长由膨压驱动，在很大程度上依赖于细胞壁：细胞壁通过合成代谢与结构重塑实现细胞扩张。此前一项研究证实，细胞壁各向同性（wall isotropy）在器官发生过程中发挥核心调控作用，其机制与皮层微管（cortical microtubules）的解聚紊乱相关。本研究表明，这种皮层微管的解聚紊乱，与参与细胞壁重塑的基因的转录调控存在耦合关联。当微管发生解聚紊乱、细胞转向各向同性生长时，其中部分基因会被诱导表达。力学建模研究显示，该耦合机制可补偿因细胞转向各向同性生长而降低的细胞扩张速率。反之，通过不同处理诱导的细胞壁松弛或细胞壁组分改变，会促进微管排列的紊乱。综上，本研究数据表明，在器官向外生长过程中存在一套被激活的调控模块，可将微管排布与细胞壁重塑过程联系起来。整体实验设计：3份Col-0样本