The REVEILLE Clock Genes Inhibit Growth of Juvenile and Adult Plants by Control of Cell Size
The REVEILLE Clock Genes Inhibit Growth of Juvenile and Adult Plants by Control of Cell Size
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DOI：
10.1104/pp.17.00109
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发表时间：
2017-04-01
期刊：
影响因子：
7.4
通讯作者：
Harmer, Stacey L.
中科院分区：
文献类型：
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作者：
Gray, Jennifer A.;Shalit-Kaneh, Akiva;Harmer, Stacey L.
生物钟是一个复杂的调节网络，在不断变化的环境中增强植物的生长和适应性。在拟南芥（Arabidopsis thaliana）中，时钟由许多调节反馈回路组成，其中REVEILLE8 （RVE8）及其同源物RVE4和RVE6以部分冗余的方式促进时钟节奏。在这里，我们报道了RVE8分支的其余成员，RVE3和RVE5，在时钟功能的调节中只起次要作用。然而，我们发现RVE8进化支蛋白在调节光输入时钟和控制植物生长的多个发育阶段具有意想不到的功能。在幼苗中，这些蛋白以日长和蔗糖依赖的方式抑制下胚轴伸长。引人注目的是，成体突变体rve4 6 8和rve3 4 5 6 8比野生型植株大得多，叶面积和生物量都有所增加。这种大小表型与更快的生长速度和更大的细胞大小有关，而不仅仅是由于向开花过渡的延迟。基因表达和上位性分析表明，rve突变体的生长表型是由于光敏色素相互作用因子4 （PHYTOCHROME INTERACTING FACTOR4, PIF4）和PIF5的表达失调所致。我们的研究结果表明，时钟基因功能的扰动引起的PIF基因表达的微小变化也会对成体植物的生长产生很大的影响。
The circadian clock is a complex regulatory network that enhances plant growth and fitness in a constantly changing environment. In Arabidopsis (Arabidopsis thaliana), the clock is composed of numerous regulatory feedback loops in which REVEILLE8 (RVE8) and its homologs RVE4 and RVE6 act in a partially redundant manner to promote clock pace. Here, we report that the remaining members of the RVE8 clade, RVE3 and RVE5, play only minor roles in the regulation of clock function. However, we find that RVE8 clade proteins have unexpected functions in the modulation of light input to the clock and the control of plant growth at multiple stages of development. In seedlings, these proteins repress hypocotyl elongation in a daylength- and sucrose-dependent manner. Strikingly, adult rve4 6 8 and rve3 4 5 6 8 mutants are much larger than wild-type plants, with both increased leaf area and biomass. This size phenotype is associated with a faster growth rate and larger cell size and is not simply due to a delay in the transition to flowering. Gene expression and epistasis analysis reveal that the growth phenotypes of rve mutants are due to the misregulation of PHYTOCHROME INTERACTING FACTOR4 (PIF4) and PIF5 expression. Our results show that even small changes in PIF gene expression caused by the perturbation of clock gene function can have large effects on the growth of adult plants.