Leaves are formed by coordinated growth of tissue layers driven by cell proliferation and expansion. Compensation, in which a defect in cell proliferation induces compensated cell enlargement (CCE), plays an important role in cell-size determination during leaf development. We previously reported that CCE triggered by the an3 mutation is observed in epidermal and subepidermal layers in Arabidopsis thaliana (Arabidopsis) leaves. Interestingly, CCE is induced in a non-cell autonomous manner between subepidermal cells. However, whether CCE in the subepidermis affects cell size in the adjacent epidermis is still unclear. We induced layer-specific expression of AN3 in an3 leaves and found that CCE in the subepidermis had little impact on cell-size determination in the epidermis, and vice versa, suggesting that CCE is induced in a tissue-autonomous manner. Examination of the epidermis in an3 leaves having AN3-positive and -negative sectors generated by Cre/loxP revealed that, in contrast to the subepidermis, CCE occurred exclusively in AN3-negative epidermal cells, indicating a cell autonomous action of an3-mediated compensation in the epidermis. These results clarified that the epidermal and subepidermal tissue layers have different cell autonomies in CCE. In addition, quantification of cell-expansion kinetics in epidermal and subepidermal tissues of the an3 showed that the tissues exhibited a similar temporal profile to reach a peak cell-expansion rate as compared to wild type. This might be one feature representing that the two tissue layers retain their growth coordination even in the presence of CCE.

中文翻译：

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an3介导的补偿取决于叶表皮组织中的细胞自主机制。

叶子是由细胞增殖和扩张驱动的组织层协调生长而形成的。补偿（其中细胞增殖缺陷诱导补偿的细胞扩大（CCE））在叶片发育过程中的细胞大小确定中起着重要作用。我们先前曾报道，在拟南芥（Arabidopsis）叶片的表皮和表皮下层中观察到an3突变触发的CCE 。有趣的是，在表皮下细胞之间以非细胞自主方式诱导CCE。但是，尚不清楚表皮下的CCE是否影响相邻表皮的细胞大小。我们在an3中诱导了AN3的层特异性表达离开后，发现表皮下的CCE对表皮中细胞大小的确定几乎没有影响，反之亦然，这表明CCE以组织自主方式被诱导。对Cre / lox P产生的具有AN3阳性和-阴性区段的an3叶片中表皮的检查显示，与下表皮相反，CCE仅发生在AN3-阴性表皮细胞中，表明an3介导的补偿的细胞自主作用在表皮中。这些结果表明，表皮和表皮下组织层在CCE中具有不同的细胞自主性。另外，在表皮和表皮下组织细胞膨胀动力学的定量AN3结果表明，与野生型相比，组织表现出相似的时间分布，以达到峰值细胞扩增速率。这可能是代表两个组织层即使在存在CCE的情况下仍保持其生长协调性的一个特征。