背景回顾：How gene activities and biomechanics together direct organ shapes is poorly understood. Plant leaf and floral organs develop from highly similar initial structures and share similar gene expression patterns, yet they gain drastically different shapes later—flat and bilateral leaf primordia and radially symmetric floral primordia, respectively. 

主要发现：We analyzed cellular growth patterns and gene expression in young leaves and flowers of Arabidopsis thaliana and found significant differences in cell growth rates, which correlate with convergence sites of phytohormone auxin that require polar auxin transport. 

结果1-叶原基：In leaf primordia, the PRESSED-FLOWER-expressing middle domain grows faster than adjacent adaxial domain and coincides with auxin convergence. 

结果2-花原基：In contrast, in floral primordia, the LEAFY-expressing domain shows accelerated growth rates and pronounced auxin convergence. 

结果3-细胞壁机械特性：This distinct cell growth dynamics between leaf and flower requires changes in levels of cell-wall pectin de-methyl-esterification and mechanical properties of the cell wall. 

结果4-计算模拟与验证：Data-driven computer model simulations at organ and cellular levels demonstrate that growth differences are central to obtaining distinct organ shape, corroborating in planta observations. 

结论：Together, our study provides a mechanistic basis for the establishment of early aerial organ symmetries through local modulation of differential growth patterns with auxin and biomechanics.

基因活性和生物力学如何一起指导器官形状仍不清楚。植物叶片和花器官发育自高度相似的初始结构，并且共享类似的表达模式，但是之后的形状大不相同，一个发育成扁平且双侧对称的叶原基，一个则发育为径向对称的花原基。本文中，作者分析了拟南芥幼嫩叶片和花的细胞生长模式和基因表达，发现二者在细胞生长速率上存在显著差异，这与极性生长素转运介导的生长素汇聚点有关。在叶片原基中，表达PRS基因的中间区域生长速度要快于相邻的近轴区域，这与生长素的汇聚一致。相反，在花原基中，表达LEAFY基因的区域表现出加速生长和明显的生长素汇聚。叶片和花的这种差异的细胞生长动态需要细胞壁果胶脱甲基酯化以及细胞壁机械特性的改变。器官和细胞水平的计算模拟说明，生长差异对于叶片和花获得不同的最终器官形状是至关重要的，植物中的观察也进一步证实了这一点。综上，本文的研究揭示了植物地上组织通过生长素和生物力学来局部调整差异性生长模式，从而建立早期器官对称性。

** 焦雨铃 **