Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.
Semin Cell Dev Biol. 2018 Nov;83:78-85. doi: 10.1016/j.semcdb.2017.09.002. Epub 2017 Sep 8.
Many organisms rely on circadian clocks to synchronize their biological processes with the 24-h rotation of the earth. In mammals, the circadian clock consists of a central clock in the suprachiasmatic nucleus and peripheral clocks in other tissues. The central clock is tightly coupled to synchronize rhythmicity and can organize peripheral clocks through neural and hormonal signals. In contrast to mammals, it has long been assumed that the circadian clocks in each plant cell is able to be entrained by external light, and they are only weakly coupled to each other. Recently, however, several reports have demonstrated that plants have unique oscillator networks with tissue-specific circadian clocks. Here, we introduce our current view regarding tissue-specific properties and oscillator networks of plant circadian clocks. Accumulating evidence suggests that plants have multiple oscillators, which show distinct properties and reside in different tissues. A direct tissue-isolation technique and micrografting have clearly demonstrated that plants have hierarchical oscillator networks consisting of multiple tissue-specific clocks.
许多生物依靠生物钟将其生物过程与地球 24 小时的旋转同步。在哺乳动物中，生物钟由视交叉上核中的中央钟和其他组织中的外周钟组成。中央钟紧密耦合以同步节奏，并通过神经和激素信号组织外周钟。与哺乳动物相比，长期以来人们一直认为每个植物细胞中的生物钟都能够被外部光线驯化，而且它们彼此之间的耦合很弱。然而，最近有几项报告表明，植物具有独特的振荡器网络，具有组织特异性的生物钟。在这里，我们介绍了我们目前对植物生物钟的组织特异性特性和振荡器网络的看法。越来越多的证据表明，植物具有多个振荡器，这些振荡器具有不同的特性并存在于不同的组织中。直接的组织分离技术和微嫁接清楚地表明，植物具有由多个组织特异性时钟组成的层次振荡器网络。
