From the cellular perspective, organ growth is determined by production and growth of cells. Uncovering how these two processes are coordinated is essential for understanding organogenesis and regulation of organ growth. We utilized phenotypic and genetic variation of 252 natural accessions of Arabidopsis thaliana to conduct genome-wide association studies (GWAS) for identifying genes underlying root growth variation; using a T-DNA line candidate approach, we identified one gene involved in root growth control and characterized its function using microscopy, root growth kinematics, G2/M phase cell count, ploidy levels and ribosome polysome profiles. We identified a factor contributing to root growth control: Arabidopsis Adenylate Kinase 6 (AAK6). AAK6 is required for normal cell production and normal cell elongation, and its natural genetic variation is involved in determining root growth differences between Arabidopsis accessions. A lack of AAK6 reduces cell production in the aak6 root apex, but this is partially compensated for by longer mature root cells. Thereby, aak6 mutants exhibit compensatory cell enlargement, a phenomenon unexpected in roots. Moreover, aak6 plants accumulate 80S ribosomes while the polysome profile remains unchanged, consistent with a phenotype of perturbed ribosome biogenesis. In conclusion, AAK6 impacts ribosome abundance, cell production and thereby root growth.

中文翻译：

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核糖体组装因子腺苷酸激酶 6 在根生长过程中维持细胞增殖和细胞大小稳态。

从细胞的角度来看，器官的生长是由细胞的产生和生长决定的。揭示这两个过程如何协调对于理解器官发生和器官生长的调节至关重要。我们利用拟南芥 252 个自然种质的表型和遗传变异进行全基因组关联研究 (GWAS)，以识别根系生长变异的基因；使用 T-DNA 系候选方法，我们确定了一个参与根生长控制的基因，并使用显微镜、根生长运动学、G2/M 期细胞计数、倍性水平和核糖体多核糖体谱表征其功能。我们确定了一个有助于根系生长控制的因素：拟南芥腺苷酸激酶 6 (AAK6)。AAK6 是正常细胞生产和正常细胞伸长所必需的，其自然遗传变异参与确定拟南芥种质之间的根生长差异。AAK6 的缺乏会降低 aak6 根尖的细胞产量，但这部分被较长成熟的根细胞所补偿。因此，aak6 突变体表现出补偿性细胞扩大，这是根中意想不到的现象。此外，aak6 植物积累 80S 核糖体，而多核糖体谱保持不变，这与受干扰的核糖体生物发生的表型一致。总之，AAK6 影响核糖体丰度、细胞生产，从而影响根系生长。根源出乎意料的现象。此外，aak6 植物积累 80S 核糖体，而多核糖体谱保持不变，这与受干扰的核糖体生物发生的表型一致。总之，AAK6 影响核糖体丰度、细胞生产，从而影响根系生长。根源出乎意料的现象。此外，aak6 植物积累 80S 核糖体，而多核糖体谱保持不变，这与受干扰的核糖体生物发生的表型一致。总之，AAK6 影响核糖体丰度、细胞生产，从而影响根系生长。