Cell autonomous and cell‐type specific circadian rhythms in Arabidopsis

Yakir, Esther; Hassidim, Miriam; Melamed-Book, Naomi; Hilman, Dror; Kron, Ido; Green, Rachel M.

doi:10.1111/j.1365-313x.2011.04707.x

Cited by 80 publications

(89 citation statements)

References 51 publications

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“…It is noteworthy that mathematical modeling suggests that the difference in clock properties between the shoot and root can be explained by light sensitivity of clock entrainment in each tissue (Bordage et al, 2016). Supporting this idea, tissue-specific clock properties, such as phase variation in clock genes, or different sensitivity to temperature signals, has been reported in intact Arabidopsis plants (Thain et al, 2002;Michael et al, 2003;Yakir et al, 2011). Recent tissue-specific microarray time-course analysis revealed that the clock genes in mesophyll cells and vascular cells show distinct expression profiles from each other ( Fig.…”

Section: Tissue Specificity In Clock Functionmentioning

confidence: 62%

Circadian Clock and Photoperiodic Flowering in Arabidopsis: CONSTANS Is a Hub for Signal Integration

2016

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Plants sense changes in day length (= photoperiod) as a reliable seasonal cue to regulate important developmental transitions such as flowering. Integration of various external light information into the circadian clock-controlled mechanisms enables plants to precisely measure photoperiod changes in the surrounding environment. The core mechanism of photoperiodic measurement is regulation of CONSTANS (CO) activity, which takes place in phloem companion cells in leaves. Until recently, it remained unclear whether plants possess specific variations of the clock for this regulation. Now it is known that a specific circadian timing mechanism in the vascular tissue is essential for photoperiodic flowering. In addition to spatial tissue-specific regulation, temporal regulation of CO activity is also important. The identification and characterization of multiple regulators that physically interact with CO and influence its function in the morning in long days are two recent advances in photoperiodic regulation of flowering time. It seems that CO acts as a network hub to integrate various external and internal signals into the photoperiodic flowering pathway. CO regulates the amount of FLOWERING LOCUS T (FT) transcripts and FT protein moves from companion cells of leaf phloem to the shoot apical meristem. The protein that helps long-distance transport of FT protein was also identified recently. Here, we introduce recent advances in tissue-specific variations of the circadian clock and the emerging picture of the intricate connections of transcriptional regulators through CO in the morning, which all facilitate plants knowing when to flower.Properly timing the floral transition is crucial for reproductive success. It can also influence the early development of offspring. To optimize this timing, plants constantly monitor changes in the surrounding environment. Among various environmental factors, observing changes in day length (= photoperiod) is the most reliable way for many organisms to know the specific time of year. Therefore, photoperiodic regulation is one of the major flowering time mechanisms and it has been studied since it was first reported in 1920 (Song et al., 2015). Arabidopsis (Arabidopsis thaliana), as it flowers mainly in spring, can sense lengthening days to induce flowering and became a suitable model to study photoperiodic flowering regulation. (Andrés and Coupland, 2012;Song et al., 2013;Pajoro et al., 2014;Shim and Imaizumi, 2015).In principle, photoperiodic flowering mechanisms can be divided into three parts: light input, circadian clock, and output. Light information is integrated into innate photoperiodic timing mechanisms governed by the circadian clock to induce genes that trigger flowering.

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Section: Tissue Specificity In Clock Functionmentioning

confidence: 62%

Circadian Clock and Photoperiodic Flowering in Arabidopsis: CONSTANS Is a Hub for Signal Integration

2016

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“…The region of 1,140 bp of the GC1 promoter that has been shown to define guard cell expression (Yang et al, 2008) was synthesized by GenScript. The construct was cloned into pMLBART, and plants were transformed and selected as described in Yakir et al (2011).…”

Section: Transgenic Plantsmentioning

confidence: 99%

“…In addition to transcriptional regulation, there is increasing evidence of other layers of regulation of oscillator components such as chromatin remodeling and protein modification (reviewed in Seo and Mas, 2014). It is likely that almost every cell in the plant has its own oscillator mechanism and the extent to which these oscillators are coupled is being explored Endo et al, 2014;Fukuda et al, 2007;Yakir et al, 2011;Thain et al, 2000;Wenden et al, 2012). There is also increasing evidence that the model of the Arabidopsis oscillator that has been widely described is an average of the oscillator mechanisms in the whole plant and that different tissues and cells, including stomatal guard cells, may have distinctive variations of the "average" mechanism (Endo et al, 2014;Para et al, 2007;James et al, 2008;Yakir et al, 2011;Takahashi et al, 2015).…”

mentioning

confidence: 99%

“…It is likely that almost every cell in the plant has its own oscillator mechanism and the extent to which these oscillators are coupled is being explored Endo et al, 2014;Fukuda et al, 2007;Yakir et al, 2011;Thain et al, 2000;Wenden et al, 2012). There is also increasing evidence that the model of the Arabidopsis oscillator that has been widely described is an average of the oscillator mechanisms in the whole plant and that different tissues and cells, including stomatal guard cells, may have distinctive variations of the "average" mechanism (Endo et al, 2014;Para et al, 2007;James et al, 2008;Yakir et al, 2011;Takahashi et al, 2015). However, further research is needed to build up a more complete picture of the similarities and differences in oscillator mechanisms in different cells as well as to understand how these variants help fit the oscillator mechanisms to the particular functions of each type of cell.…”

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confidence: 99%

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CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and the Circadian Control of Stomatal Aperture

et al. 2017

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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 SGC (specifically guard cell) Arabidopsis (Arabidopsis thaliana) plants in which the oscillator gene CIRCADIAN CLOCK ASSOCIATED1 (CCA1) was overexpressed under the control of the guard-cell-specific promoter, GC1. The SGC 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, SGC 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 CCA1. 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.

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“…To understand the role of [Ca 2+ ] cyt in the circadian network, it is necessary to determine specifically in which cells [Ca 2+ ] cyt functions in the circadian clock. All plant cells are believed to have circadian rhythms that are cell autonomous Yakir et al, 2011). There is evidence of tissue-specific circadian behavior; for example, the vascular bundle circadian clock appears to have a different genetic architecture compared with other tissues (Para et al, 2007).…”

Section: Localization Of Nycthemeral and Circadian Oscillations Of [Cmentioning

confidence: 99%

Cell- and Stimulus Type-Specific Intracellular Free Ca2+ Signals in Arabidopsis

2013

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Appropriate stimulus-response coupling requires that each signal induces a characteristic response, distinct from that induced by other signals, and that there is the potential for individual signals to initiate different downstream responses dependent on cell type. How such specificity is encoded in plant signaling is not known. One possibility is that information is encoded in signal transduction pathways to ensure stimulus-and cell type-specific responses. The calcium ion acts as a second messenger in response to mechanical stimulation, hydrogen peroxide, NaCl, and cold in plants and also in circadian timing. We use GAL4 transactivation of aequorin in enhancer trap lines of Arabidopsis (Arabidopsis thaliana) to test the hypothesis that stimulus-and cell-specific information can be encoded in the pattern of dynamic alterations in the concentration of intracellular free Ca 2+ ( ] i dynamics in response to touch, cold, and hydrogen peroxide, which in the case of the latter two signals are common to all cell types tested. GAL4 transactivation of aequorin in specific leaf cell types has allowed us to bypass the technical limitations associated with fluorescent Ca 2+ reporter dyes in chlorophyll-containing tissues to identify the cell-and stimulus-specific complexity of [Ca 2+ ] i dynamics in leaves of Arabidopsis and to determine from which tissues stress-and circadian-regulated [Ca 2+ ] i signals arise. Ca2+ is an important second messenger involved in a wide range of responses in plants (Dodd et al., 2010 (Dodd et al., 2010). However, the utility of fluorescent Ca 2+ indicators in plants has been usually restricted to a few specific cell types, including the guard cells, root hairs, and pollen tubes, because these tissues are low in chlorophyll. In other tissues, chlorophyll fluorescence reduces the signal-to-noise ratio to unacceptable levels. Furthermore, in situ measurements of cytosolic-free Ca 2+ concentration ([Ca 2+

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Cell autonomous and cell‐type specific circadian rhythms in Arabidopsis

Cited by 80 publications

References 51 publications

Circadian Clock and Photoperiodic Flowering in Arabidopsis: CONSTANS Is a Hub for Signal Integration

Circadian Clock and Photoperiodic Flowering in Arabidopsis: CONSTANS Is a Hub for Signal Integration

CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and the Circadian Control of Stomatal Aperture

Cell- and Stimulus Type-Specific Intracellular Free Ca2+ Signals in Arabidopsis

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