Department of Cell and Developmental Biology, John Innes Centre, Colney Lane, Norwich NR47UH, UK.
Curr Biol. 2010 Mar 23;20(6):527-32. doi: 10.1016/j.cub.2010.01.039. Epub 2010 Feb 25.
Growth control in animals and plants involves mobile signals. Depending on their range of action, these signals coordinate the growth of cells within an organ or the growth of different organs in a larger, functionally integrated structure. In plants, flowers are such integrated structures, yet it remains poorly understood how growth of the constituent organs is coordinated to ensure their correct relative sizes. The cytochrome P450 KLUH/CYP78A5 and its homolog CYP78A7 promote organ growth via a non-cell-autonomous signal; however, the range of this signal and thus its developmental function are unknown. Here we use a system for the predictable generation of chimeric plants to determine the range of the KLUH-dependent signal. In contrast with the largely autonomous behavior of another tested growth-control gene, we find that KLUH activity extends beyond individual organs and flowers. Its overall activity is integrated across an inflorescence to determine final organ size, which is largely independent of the genotype of the individual organs. Thus, the KLUH-dependent signal appears to move beyond individual organs in a flower, providing a mechanism for coordinating their growth and ensuring floral symmetry as an important determinant of a plant's attractiveness to pollinators.
动植物的生长控制涉及移动信号。这些信号根据其作用范围，协调器官内细胞的生长或更大的、功能上整合的结构中不同器官的生长。在植物中，花是这样的整合结构，但仍然不清楚如何协调组成器官的生长，以确保它们的正确相对大小。细胞色素 P450 KLUH/CYP78A5 及其同源物 CYP78A7 通过非细胞自主信号促进器官生长；然而，这种信号的范围及其发育功能尚不清楚。在这里，我们使用一种可预测产生嵌合体植物的系统来确定 KLUH 依赖性信号的范围。与另一个经过测试的生长控制基因的自主性行为相比，我们发现 KLUH 活性超出了单个器官和花朵的范围。它的整体活性在整个花序中整合，以确定最终器官的大小，这在很大程度上独立于单个器官的基因型。因此，KLUH 依赖性信号似乎在花朵中的单个器官之外移动，为协调它们的生长提供了一种机制，并确保花的对称性作为植物对传粉者吸引力的一个重要决定因素。
