Department of Plant and Environmental Sciences, The Silberman Institute for Life Sciences, The Hebrew University, Givat Ram, Jerusalem 91904, Israel.
Department of Plant and Environmental Sciences, The Silberman Institute for Life Sciences, The Hebrew University, Givat Ram, Jerusalem 91904, Israel
Plant Physiol. 2017 Dec;175(4):1864-1877. doi: 10.1104/pp.17.01214. Epub 2017 Oct 30.
The endogenous circadian (∼24 h) system allows plants to anticipate and adapt to daily environmental changes. Stomatal aperture is one of the many processes under circadian control; stomatal opening and closing occurs under constant conditions, even in the absence of environmental cues. To understand the significance of circadian-mediated anticipation in stomatal opening, we have generated (specifically guard cell) Arabidopsis () plants in which the oscillator gene () was overexpressed under the control of the guard-cell-specific promoter, The plants showed a loss of ability to open stomata in anticipation of daily dark-to-light changes and of circadian-mediated stomatal opening in constant light. We observed that under fully watered and mild drought conditions, plants outperform wild type with larger leaf area and biomass. To investigate the molecular basis for circadian control of guard cell aperture, we used large-scale qRT-PCR to compare circadian oscillator gene expression in guard cells compared with the "average" whole-leaf oscillator and examined gene expression and stomatal aperture in several lines of plants with misexpressed Our results show that the guard cell oscillator is different from the average plant oscillator. Moreover, the differences in guard cell oscillator function may be important for the correct regulation of photoperiod pathway genes that have previously been reported to control stomatal aperture. We conclude by showing that CONSTANS and FLOWERING LOCUS T, components of the photoperiod pathway that regulate flowering time, also control stomatal aperture in a daylength-dependent manner.
内源性的昼夜节律（∼24 小时）系统使植物能够预测和适应每日的环境变化。气孔孔径是受昼夜节律控制的众多过程之一；即使在没有环境线索的情况下，气孔也会在恒 定条件下打开和关闭。为了理解昼夜节律介导的气孔开放预测的意义，我们已经生成了（特别是保卫细胞）拟南芥（）植物，其中振荡器基因（）在保卫细胞特异性启动子的控制下过表达。这些植物表现出丧失了在预期的每日暗至光变化和昼夜节律介导的恒定光下开放气孔的能力。我们观察到，在充分浇水和轻度干旱条件下，与野生型相比，具有更大的叶面积和生物量。为了研究昼夜节律对保卫细胞孔径的控制的分子基础，我们使用大规模 qRT-PCR 比较了与“平均”整叶振荡器相比，在保卫细胞中昼夜节律振荡器基因的表达，并检查了几个过表达的植物系中的基因表达和气孔孔径。我们的结果表明，保卫细胞振荡器与平均植物振荡器不同。此外，保卫细胞振荡器功能的差异可能对正确调节先前报道控制气孔孔径的光周期途径基因很重要。我们通过显示光周期途径的组成部分 CONSTANS 和 FLOWERING LOCUS T 也以依赖于日长的方式控制气孔孔径来得出结论。
