The Arabidopsis petal: a model for plant organogenesis

Irish, Vivian F.

doi:10.1016/j.tplants.2008.05.006

Cited by 100 publications

(110 citation statements)

References 84 publications

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“…In Arabidopsis, petals have a simple laminar structure with a small number of cell types, facilitating the analysis of organ growth and development (Irish, 2008). As the most dramatic phenotypic alteration in med25 mutants was in flowers, and especially petals, we used the petal as a representative organ to further investigate the cellular basis of the increase in organ size.…”

Section: Med25-2 Increases the Period Of Cell Proliferation And Cell mentioning

confidence: 99%

Control of final organ size by Mediator complex subunit 25 in Arabidopsis thaliana

2011

Development

113

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Control of organ size by cell proliferation and cell expansion is a fundamental developmental process, but the mechanisms that establish the final size of organs and whole organisms remain elusive in plants and animals. We have previously demonstrated that DA1, which encodes a predicted ubiquitin receptor, controls the final size of seeds and organs by restricting cell proliferation in Arabidopsis. Through a genetic screen for mutations that enhance the floral organ size of da1-1, we have identified an enhancer of da1-1 (eod8-1). The eod8-1 mutation was identified, using a map-based cloning approach, in Mediator complex subunit 25 (MED25; also known as PFT1), which is involved in the transcriptional regulation of gene expression. Loss-of-function mutants in MED25 form large organs, with larger and slightly increased numbers of cells as a result of an increased period of cell proliferation and cell expansion, whereas plants overexpressing MED25 have small organs owing to decreases in both cell number and cell size. Our genetic and physiological data suggest that MED25 acts to limit cell and organ growth independently of MED25-mediated phytochrome signaling and the jasmonate pathway. Genetic analyses show that MED25 functions redundantly with DA1 to control organ growth by restricting cell proliferation. Collectively, our findings show that MED25 plays a crucial role in setting final organ size, suggesting that it constitutes an important point of regulation in plant organ size control within the transcriptional machinery.

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Section: Med25-2 Increases the Period Of Cell Proliferation And Cell mentioning

confidence: 99%

Control of final organ size by Mediator complex subunit 25 in Arabidopsis thaliana

2011

Development

113

132

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“…Disruption of petal initiation is frequent among floral mutants of Arabidopsis (Irish, 2008), suggesting that the threshold of response to signalling may be finely balanced. This could be a consequence of the relatively few founder cells involved (Bossinger and Smyth, 1996).…”

Section: Introductionmentioning

confidence: 99%

Auxin controls petal initiation in Arabidopsis

2013

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SUMMARYFloral organs are usually arranged in concentric whorls of sepals, petals, stamens and carpels. How founder cells of these organs are specified is unknown. In Arabidopsis, the PETAL LOSS (PTL) transcription factor functions in the sepal whorl, where it restricts the size of the inter-sepal zone. Genetic evidence suggests that PTL acts to support a petal initiation signal active in the adjacent whorl. Here we aimed to characterise the signal by identifying enhancers that disrupt initiation of the remaining petals in ptl mutants. One such enhancer encodes the auxin influx protein AUX1. We have established that auxin is a direct and mobile petal initiation signal by promoting its biosynthesis in the inter-sepal zone in ptl mutant plants and restoring nearby petal initiation. Consistent with this, loss of PTL function disrupts DR5 expression, an auxin-inducible indicator of petal-initiation sites. The signalling network was extended by demonstrating that: (1) loss of RABBIT EARS (RBE) function apparently disrupts the same auxin influx process as PTL; (2) the action of AUX1 is supported by AXR4, its upstream partner in auxin influx; (3) polar auxin transport, which is controlled by PINOID (PID) and PIN-FORMED1 (PIN1), functions downstream of PTL; and (4) the action of pmd-1d, a dominant modifier of the ptl mutant phenotype, is dependent on auxin transport. Thus, loss of PTL function disrupts auxin dynamics, allowing the role of auxin in promoting petal initiation to be revealed.

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“…For example, most plants in the Brassicaceae family have four-petal flowers, like Arabidopsis. The production of four petals in Arabidopsis requires genes that control meristem size, lateral organ outgrowth, and polarity, but also genes that confer petal identity and establish boundaries that demarcate the position of petals on the floral meristem (Irish, 2008;Huang and Irish, 2016). A critical step in this process is the suppression of growth in the regions between sepals, which creates space for auxin-induced petal initiation on the floral meristem (Huang et al, 2012;Lampugnani et al, 2013).…”

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confidence: 99%

Seasonal Regulation of Petal Number

et al. 2017

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Four petals characterize the flowers of most species in the Brassicaceae family, and this phenotype is generally robust to genetic and environmental variation. A variable petal number distinguishes the flowers of Cardamine hirsuta from those of its close relative Arabidopsis (Arabidopsis thaliana), and allelic variation at many loci contribute to this trait. However, it is less clear whether C. hirsuta petal number varies in response to seasonal changes in environment. To address this question, we assessed whether petal number responds to a suite of environmental and endogenous cues that regulate flowering time in C. hirsuta. We found that petal number showed seasonal variation in C. hirsuta, such that spring flowering plants developed more petals than those flowering in summer. Conditions associated with spring flowering, including cool ambient temperature, short photoperiod, and vernalization, all increased petal number in C. hirsuta. Cool temperature caused the strongest increase in petal number and lengthened the time interval over which floral meristems matured. We performed live imaging of early flower development and showed that floral buds developed more slowly at 15°C versus 20°C. This extended phase of floral meristem formation, coupled with slower growth of sepals at 15°C, produced larger intersepal regions with more space available for petal initiation. In summary, the growth and maturation of floral buds is associated with variable petal number in C. hirsuta and responds to seasonal changes in ambient temperature.

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The Arabidopsis petal: a model for plant organogenesis

Cited by 100 publications

References 84 publications

Control of final organ size by Mediator complex subunit 25 in Arabidopsis thaliana

Control of final organ size by Mediator complex subunit 25 in Arabidopsis thaliana

Auxin controls petal initiation in Arabidopsis

Seasonal Regulation of Petal Number

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