Importance of epidermal clocks for regulation of hypocotyl elongation through PIF4 and IAA29
Importance of epidermal clocks for regulation of hypocotyl elongation through PIF4 and IAA29
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DOI：
10.1080/15592324.2016.1143999
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发表时间：
2016-02
影响因子：
2.9
通讯作者：
Hanako Shimizu;Kotaro Torii;T. Araki;Motomu Endo
中科院分区：
文献类型：
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作者：
Hanako Shimizu;Kotaro Torii;T. Araki;Motomu Endo
生物钟调节生物体与环境有关的生理反应。在植物中，最近提出了一种分散的生物钟系统。表皮时钟功能对细胞伸长至关重要；因此，在27℃下，表皮特异的CCA1过表达导致较小的子叶和较长的下胚轴，并伴随着夜间PIF4 mRNA水平的升高。然而，哪个组织的时钟调节PIF4的表达仍然是一个悬而未决的问题。在这里，我们测试了PIF4及其下游靶标IAA29在有或没有表皮时钟扰动的情况下的空间表达模式。利用表皮特异表达系统，我们发现表皮时钟扰动增加了PIF4在表皮和叶肉中的表达。然而，IAA29的表达主要在表皮中调节，这意味着表皮在通过PIF4和IAA29调节细胞伸长方面具有潜在的重要性。我们的结论是，表皮中的生物钟主要在表皮调节细胞的伸长，还存在从表皮到叶肉的另一种组织间信号通路。
Abstract Circadian clocks adjust an organism's environmentally relevant physiological responses.. In plants, a decentralized circadian clock system has recently been proposed. Epidermal clock function is crucial for cell elongation; thus, epidermis-specific overexpression of CCA1 caused smaller cotyledons and longer hypocotyls under 27°C, concomitant with elevated night time levels of PIF4 mRNA. However, which tissue's clock regulates PIF4 expression is still an open question. Here we tested spatial expression patterns of PIF4 and its downstream target IAA29 with or without epidermal clock perturbation. Using an epidermal-specific expression system, we revealed that epidermal clock perturbation increases PIF4 expression in both epidermis and mesophyll. However, IAA29 expression is mainly regulated in the epidermis, implying the potential importance of epidermis for regulation of cell elongation through PIF4 and IAA29. We conclude that the circadian clock in epidermis regulates cell elongation mainly in epidermis, and there is also another inter-tissue signaling pathway from epidermis to mesophyll.