Singh Yadav Avilash, Hong Lilan, Klees Patrick M, Kiss Annamaria, Petit Manuel, He Xi, Barrios Iselle M, Heeney Michelle, Galang Anabella Maria D, Smith Richard S, Boudaoud Arezki, Roeder Adrienne H K
Weill Institute for Cell and Molecular Biology and Section of Plant Biology, School of Integrative Plant Sciences, Cornell University, Ithaca, NY 14853, USA.
Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
bioRxiv. 2025 Apr 2:2023.07.22.549953. doi: 10.1101/2023.07.22.549953.
From smooth shapes to buckles, nature exhibits organs of various shapes and forms. How cells grow to produce smooth shaped leaves and sepals remain unclear. Here, we show that growth along the longitudinal axis during early developmental stages and comparable stiffness across both epidermal layers of Arabidopsis sepals are essential for smoothness, as seen in the wild type. We identified a mutant () with ectopic expression of () on the outer epidermis. Our analysis reveals that ectopic expression causes the outer epidermis of sepals to buckle during early stages of sepal development. We show that buckling of the outer epidermis occurs due to conflicting cell growth directions and unequal tissue stiffness across the epidermal layers. Overexpression of cyclin-dependent kinase (CDK) inhibitor Kip-related protein 1 (KRP1) in restores sepal smoothness by aligning the growth directions of the outer epidermal cells along the longitudinal axis, while also increasing the overall stiffness of the outer epidermis. Furthermore, buckling is associated with the convergence of auxin efflux transporter protein PIN-FORMED 1 (PIN1) to generate outgrowth in the sepals at later stages, suggesting that buckling can initiate outgrowths. Our findings suggest that in addition to molecular cues influencing tissue mechanics, tissue mechanics can also modulate molecular signals, giving rise to well-defined shapes.
从光滑的形状到褶皱，自然界展现出各种形状和形态的器官。细胞如何生长以产生形状光滑的叶子和萼片仍不清楚。在这里，我们表明，如在野生型中所见，拟南芥萼片早期发育阶段沿纵向轴的生长以及两个表皮层相当的硬度对于光滑度至关重要。我们鉴定出一个在外表皮上异位表达（）的突变体（）。我们的分析表明，异位表达导致萼片外表皮在萼片发育早期阶段发生褶皱。我们表明，外表皮的褶皱是由于细胞生长方向冲突以及表皮层间组织硬度不均所致。在（）中过表达细胞周期蛋白依赖性激酶（CDK）抑制剂Kip相关蛋白1（KRP1），通过使外表皮细胞的生长方向沿纵向轴排列，同时增加外表皮的整体硬度，从而恢复萼片的光滑度。此外，褶皱与生长素外流转运蛋白PIN-FORMED 1（PIN1）的汇聚相关，从而在后期阶段在萼片中产生突出物，这表明褶皱可以引发突出物。我们的研究结果表明，除了分子线索影响组织力学外，组织力学也可以调节分子信号，从而产生明确的形状。
