Highly expressed cell wall genes contribute to robustness of sepal size

Reproducibility in organ size and shape is a fascinating trait of living organisms. The mechanisms underlying such robustness remain, however, to be elucidated. Taking the sepal of Arabidopsis as a model, we investigated whether variability of gene expression plays a role in variation of organ size and shape. Previous work from our team identified cell-wall related genes as being enriched among the genes whose expression is highly variable. We then hypothesized that the variation of measured morphological parameters in cell-wall related single knockout mutants could be correlated with the variation in gene expression of the corresponding gene (the knocked-out gene) in wild-type plants. We analyzed sepal size and shape from 16 cell-wall mutants and found that sepal size variability correlates positively, not with gene expression variation, but with mean gene expression of the corresponding gene in wild type. These findings support a contribution of cell-wall related genes to the robustness of sepal size.

生物体器官尺寸与形态的可重现性是一项极具魅力的生命特征。然而，支撑这种鲁棒性的分子机制仍有待阐明。本研究以拟南芥（Arabidopsis）花萼为实验模型，探究基因表达变异是否会参与调控器官尺寸与形态的变异过程。本团队此前的研究发现，细胞壁相关基因在表达水平高度变异的基因中显著富集。据此我们提出假说：细胞壁相关单基因敲除突变体中测得的形态学参数变异程度，可与野生型植株中对应敲除基因的表达变异程度存在关联。我们对16个细胞壁相关突变体的花萼尺寸与形态进行分析后发现：花萼尺寸的变异程度与基因表达变异并无正向相关性，而是与野生型植株中对应基因的平均表达水平呈显著正相关。上述研究结果证实，细胞壁相关基因可参与维持花萼尺寸的鲁棒性。