Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, 69364 Lyon Cedex, France.
Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, 40-032 Katowice, Poland.
Cell Rep. 2023 Jul 25;42(7):112689. doi: 10.1016/j.celrep.2023.112689. Epub 2023 Jun 22.
Extracellular matrices contain fibril-like polymers often organized in parallel arrays. Although their role in morphogenesis has been long recognized, it remains unclear how the subcellular control of fibril synthesis translates into organ shape. We address this question using the Arabidopsis sepal as a model organ. In plants, cell growth is restrained by the cell wall (extracellular matrix). Cellulose microfibrils are the main load-bearing wall component, thought to channel growth perpendicularly to their main orientation. Given the key function of CELLULOSE SYNTHASE INTERACTIVE1 (CSI1) in guidance of cellulose synthesis, we investigate the role of CSI1 in sepal morphogenesis. We observe that sepals from csi1 mutants are shorter, although their newest cellulose microfibrils are more aligned compared to wild-type. Surprisingly, cell growth anisotropy is similar in csi1 and wild-type plants. We resolve this apparent paradox by showing that CSI1 is required for spatial consistency of growth direction across the sepal.
细胞外基质包含纤维状聚合物，这些聚合物通常以平行排列的方式组织在一起。尽管它们在形态发生中的作用早已被认识，但细胞内对纤维合成的控制如何转化为器官形状仍不清楚。我们使用拟南芥萼片作为模型器官来解决这个问题。在植物中，细胞生长受到细胞壁（细胞外基质）的限制。纤维素微纤维是主要的承载细胞壁成分，被认为沿其主要方向垂直引导生长。鉴于 CELLULOSE SYNTHASE INTERACTIVE1（CSI1）在纤维素合成指导中的关键功能，我们研究了 CSI1 在萼片形态发生中的作用。我们观察到 csi1 突变体的萼片较短，尽管与野生型相比，它们最新的纤维素微纤维排列更整齐。令人惊讶的是，csi1 和野生型植物中的细胞生长各向异性相似。我们通过表明 CSI1 是在萼片上保持生长方向的空间一致性所必需的，解决了这个明显的悖论。
