References of "D'Aloia, Maria"
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See detailFlowering Goes Underground
Bouché, Frédéric ULg; Lobet, Guillaume ULg; D'Aloia, Maria ULg et al

Conference (2014, May 15)

Flowering is a crucial step in plant life cycle and is therefore tightly controlled by both environmental and endogenous cues. The involvement of the aerial organs of the plant in the molecular mechanisms ... [more ▼]

Flowering is a crucial step in plant life cycle and is therefore tightly controlled by both environmental and endogenous cues. The involvement of the aerial organs of the plant in the molecular mechanisms controlling floral transition has been extensively documented while the participation of the roots remains poorly investigated. However, the induction of flowering by photoperiod involves systemic signals that move in the phloem from leaves to sinks, and hence presumably reach the roots. We therefore performed a transcriptomic analysis of the roots during the induction of flowering in Arabidopsis thaliana and indeed identified a large number of differentially expressed genes. A reverse genetic approach further confirmed the pleiotropic effects of flowering time genes on root architecture. [less ▲]

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See detailThe hidden half of flowering
Bouché, Frédéric ULg; Mistiaen, Kevin ULg; D'Aloia, Maria ULg et al

Poster (2013, June)

Flowering is one of the most important developmental steps in plant life cycle and is therefore tightly controlled by environmental cues. The involvement of the aerial part of the plant in the molecular ... [more ▼]

Flowering is one of the most important developmental steps in plant life cycle and is therefore tightly controlled by environmental cues. The involvement of the aerial part of the plant in the molecular mechanisms leading to floral transition is well documented while participation of the roots received less attention. Nevertheless, the induction of flowering by photoperiod is known to involve systemic signals that move in phloem sap towards sinks, throughout the plants, including the roots. Transcriptomic analysis of roots tissues during the floral induction of flowering by a single long day of in Arabidopsis thaliana by a single long day allowed us to identify a large number of differentially expressed genes. How mutations We subsequently selected in some candidate genes affect plant development - including root architecture and flowering time - is being to analyze their flowering timefurther analyzed. Further analysis of those genes will permit us to unravel their role in the flowering induction process. [less ▲]

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See detailA root chicory MADS-box sequence and the Arabidopsis flowering repressor FLC share common features that suggest conserved function in vernalization and devernalization responses
Périlleux, Claire ULg; Pieltain, Alexandra; Jacquemin, Guillaume et al

in Plant Journal (The) (2013), 75

Root chicory (Cichorium intybus var. sativum) is a biennial crop, but is harvested for root inulin at the end of the first growing season before flowering. However, cold temperatures might vernalize seeds ... [more ▼]

Root chicory (Cichorium intybus var. sativum) is a biennial crop, but is harvested for root inulin at the end of the first growing season before flowering. However, cold temperatures might vernalize seeds or plantlets, leading to incidental early flowering and hence understanding the molecular basis of vernalization is important. A MADS-box sequence was isolated by RT-PCR and named FLC-LIKE1 (CiFL1) because of its phylogenetic positioning within the same clade as the floral repressor Arabidopsis FLOWERING LOCUS C (AtFLC). Moreover, overexpression of CiFL1 in Arabidopsis caused late flowering and prevented up-regulation of the AtFLC target FLOWERING LOCUS T gene by photoperiod, suggesting functional conservation between root chicory and Arabidopsis. Like AtFLC in Arabidopsis, CiFL1 was repressed during vernalization of seeds or plantlets of chicory, but repression of CiFL1 was unstable whether the post-vernalization temperature was favorable to flowering or whether it devernalized the plants. Instability of CiFL1 repression might be linked to bienniality of root chicory versus the annual life cycle of Arabidopsis. However, reactivation of AtFLC was also observed in Arabidopsis when a high temperature treatment was given straight after seed vernalization, erasing the promotive effect of cold on flowering. Cold-induced downregulation of a MADS-box floral repressor and its reactivation by high temperature thus appear as conserved features of the vernalization and devernalization responses in distant species.This article is protected by copyright. All rights reserved. [less ▲]

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See detailRooting the flowering process
D'Aloia, Maria ULg; Bouché, Frédéric ULg; Tamseddak, Karim et al

Poster (2012, May)

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See detailTranscriptomic analysis of Arabidopsis roots during floral induction by photoperiod
D'Aloia, Maria ULg; Lamoureux, Thibaut ULg; Tocquin, Pierre ULg et al

Poster (2011, June)

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. We used an ... [more ▼]

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. We used an hydroponic device that allows synchronous growth and flowering of Arabidopsis and performed global transcript profiling of roots. Samples were harvested during the extension period of a single long day (LD), and in non inductive short day. Microarray data were validated by real-time RT-PCR, and the expression patterns of selected probes were further analyzed in shoots and roots. Some of the genes that were differentially expressed in the roots during the inductive LD did not show the same variations in the shoot, indicating that root transcriptome undergoes specific changes at floral transition. These genes include, for example, GIGANTEA. T-DNA mutants from selected candidate genes are being studied. Both the expression analysis and the reverse genetic approach provide new insights into the contribution of the roots to the flowering process. [less ▲]

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See detailA cytokinin route to flowering in Arabidopsis
Bouché, Frédéric ULg; André, Julie ULg; D'Aloia, Maria ULg et al

Poster (2011, June)

Cytokinins (CKs) are involved in many physiological processes. We observed that the application of N6-benzylaminopurine (BAP) to the roots of hydroponically grown plants of Arabidopsis thaliana promotes ... [more ▼]

Cytokinins (CKs) are involved in many physiological processes. We observed that the application of N6-benzylaminopurine (BAP) to the roots of hydroponically grown plants of Arabidopsis thaliana promotes flowering in non-inductive short days. The response to BAP treatment does no require FLOWERING LOCUS T (FT), but activates its paralogue TWIN SISTER OF FT (TSF), as well as FD and SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1) (D'Aloia et al., 2011). We present here complementary data obtained with transgenic plants overexpressing a catalytic CK OXIDASE/DEHYDROGENASE (CKX) in the roots. The high efficiency of BAP in promoting flowering in our experimental system contrasts with the variability that emerges from studies gathered in literature. Many factors, either experimental or inherent to plant material, might explain these discrepancies and we are interested in identifying endogenous regulators that might provide a mechanistic explanation. We are therefore investigating whether the endogenous pathways underlying plant developmental phase changes might regulate the relative contribution of CKs to flowering. [less ▲]

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See detailCytokinin promotes flowering of Arabidopsis via transcriptional activation of the FT paralogue TSF
D'Aloia, Maria ULg; Bonhomme, Delphine ULg; Bouché, Frédéric ULg et al

in Plant Journal (The) (2011), 65

Cytokinins are involved in many aspects of plant growth and development and physiological evidence also indicates that they have a role in floral transition. In order to integrate these phytohormones into ... [more ▼]

Cytokinins are involved in many aspects of plant growth and development and physiological evidence also indicates that they have a role in floral transition. In order to integrate these phytohormones into the current knowledge of genetically defined molecular pathways to flowering, we performed exogenous treatments of adult wild-type and mutant Arabidopsis plants and analysed the expression of candidate genes. We used a hydroponic system that enables synchronous growth and flowering of Arabidopsis and allows precise application of chemicals to the roots for defined periods of time. We show that application of N6-benzylaminopurine (BAP) promotes flowering of plants grown in non-inductive short days. The response to cytokinin treatment does not require FLOWERING LOCUS T (FT) but activates its paralogue TWIN SISTER OF FT (TSF), as well as FD, which encodes a partner protein of TSF, and the downstream gene SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1). Treatment of selected mutants confirmed that TSF and SOC1 are necessary for the flowering response to BAP while the activation cascade might partially act independently of FD. These experiments provide a mechanistic basis for the role of cytokinins in flowering and demonstrate that the redundant genes FT and TSF are differently regulated by distinct floral inducing signals. [less ▲]

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See detailTranscriptomic analysis of Arabidopsis roots during flowering
D'Aloia, Maria ULg; Tocquin, Pierre ULg; Périlleux, Claire ULg

Poster (2010, February)

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. Taking advantage of ... [more ▼]

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. Taking advantage of an hydroponic device that allows synchronous growth and flowering of Arabidopsis thaliana (Tocquin et al., 2003), we performed global transcript profiling of roots during induction of flowering by a single long day (LD). Results were validated by real-time RT-PCR, and the expression patterns of selected probes were further analyzed in shoots and roots. Some of the genes that were identified in the microarray experiment were already known to be involved in the photoperiodic pathway of flowering in Arabidopsis, and hence were activated in both roots and shoots during the LD. These genes include, for example, components of light signaling or circadian machinery (e.g. GIGANTEA). Other genes providing new insights into the control of flowering at the whole plant level will be presented. Tocquin et al., (2003). BMC Plant Biology, 3: 2. [less ▲]

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See detailFunctional analysis of an FLC-LIKE gene in root chicory
Périlleux, Claire ULg; Pieltain, Alexandra ULg; D'Aloia, Maria ULg et al

in Comparative Biochemistry and Physiology. Part A, Physiology (2009), 153A(2/Suppl.), 198-199

Vernalization is known to promote flowering in Arabidopsis thaliana by inhibiting the expression of a strong repressor: FLOWERING LOCUS C (FLC). The recent cloning of an FLC-LIKE gene in sugar beet (Beta ... [more ▼]

Vernalization is known to promote flowering in Arabidopsis thaliana by inhibiting the expression of a strong repressor: FLOWERING LOCUS C (FLC). The recent cloning of an FLC-LIKE gene in sugar beet (Beta vulgaris; BvFL1) and – here – in root chicory (Cichorium intybus; CiFL1) suggests the conservation of FLC biological function during evolution of eudicots. Hence physiological questions that remain difficult to address in Arabidopsis can be studied in other species. We investigated the correlation between CiFL1 expression and plant-age dependent responsiveness to vernalization. We also studied the effect of post-vernalization growing temperature, which can stabilize or erase the vernalized state. [less ▲]

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See detailGene activation cascade triggered by a single photoperiodic cycle inducing flowering in Sinapis alba
D'Aloia, Maria ULg; Tamseddak, Karim; Bonhomme, Delphine ULg et al

in The Plant Journal (2009), 59

Molecular genetic analyses in Arabidopsis disclosed a genetic pathway whereby flowering is induced by the photoperiod. This cascade is examined here within the time course of floral transition in the long ... [more ▼]

Molecular genetic analyses in Arabidopsis disclosed a genetic pathway whereby flowering is induced by the photoperiod. This cascade is examined here within the time course of floral transition in the long-day (LD) plant Sinapis alba induced by a single photoperiodic cycle. In addition to previously available sequences, the cloning of CONSTANS (SaCO) and FLOWERING LOCUS T (SaFT) homologues allowed expression analyses to be performed to follow the flowering process step by step. A diurnal rhythm in SaCO expression in the leaves was observed and transcripts of SaFT were detected when light was given in phase with SaCO kinetics only. This occurred when day length was extended or when a short day was shifted towards a ‘photophile phase’. The steady-state level of SaFT transcripts in the various physiological situations examined was found to correlate like a rheostat with floral induction strength. Kinetics of SaFT activation were also consistent with previous estimations of translocation of florigen out of leaves, which could actually occur after the inductive cycle. In response to one 22-h LD, initiation of floral meristems by the shoot apical meristem (SAM) started about 2 days after activation of SaFT and was marked by expression of APETALA1 (SaAP1). Meanwhile, LEAFY (SaLFY) was first up-regulated in leaf primordia and in the SAM. FRUITFULL (SaFUL) was later activated in the whole SAM but excluded from floral meristems. These patterns are integrated with previous observations concerning upregulation of SUPPRESSOR OF OVEREXPRESSION OF CO1 (SaSOC1) to provide a temporal and spatial map of floral transition in Sinapis. [less ▲]

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See detailAn FLC-like gene is controlled by vernalization in root chicory
Périlleux, Claire ULg; Pieltain, Alexandra ULg; D'Aloia, Maria ULg et al

Poster (2008, September)

Vernalization is known to promote flowering in Arabidopsis via the repression by cold of the floral inhibitor gene FLOWERING LOCUS C (FLC). For long, FLC homologs have been found in Brassicaceae only but ... [more ▼]

Vernalization is known to promote flowering in Arabidopsis via the repression by cold of the floral inhibitor gene FLOWERING LOCUS C (FLC). For long, FLC homologs have been found in Brassicaceae only but it was recently reported that in sugar beet, the FLC-like gene BvFL1 functions as a repressor of flowering and is downregulated in response to cold. We describe here the cloning of CiFL1 from root chicory (Cichorium intybus). Expression patterns were studied in two cultivars, differing in their sensitivity to vernalization. Transcript level analyzes were performed during the vernalization treatment of the seedlings and in different post-vernalization conditions. Our results give further support to conservation of the biological function of FLC-like genes in eudicot species. [less ▲]

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See detailControl of floral transition in maize
Van Kerkhoven, Fabrizio ULg; D'Aloia, Maria ULg; Périlleux, Claire ULg

Conference (2008, September)

Flowering time in plants is controlled by a number of environmental factors, among which photoperiod plays a key role. Maize ancestors are short-day (SD) plants, but breeding programs have selected ... [more ▼]

Flowering time in plants is controlled by a number of environmental factors, among which photoperiod plays a key role. Maize ancestors are short-day (SD) plants, but breeding programs have selected genotypes whose flowering is largely autonomous and occurs after production of a constant number of leaves regardless of photoperiod. Only few flowering time genes have been identified in maize; one of them is INDETERMINATE1 (ID1), cloned from a late-flowering mutant and encoding a zinc finger transcription factor. By contrast, the genetical control of flowering by photoperiod is best understood in the long-day (LD) dicot Arabidopsis and the SD monocot rice. A key regulator is the CONSTANS gene that mediates between the circadian clock – the time-keeper of the plant – and the synthesis of flowering signals. Here we report the analysis of a CONSTANS homolog in maize, ZmCO, in SD and in LD, and in different parts of the plant. Expression of ZmCO was found to be rhythmic and to be much higher in young leaf primordia than in mature leaf blades. Striking coincidence was observed with expression of ID1. [less ▲]

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See detailVernalization-induced repression of FLOWERING LOCUS C stimulates flowering in Sinapis alba and enhances plant responsiveness to photoperiod.
D'Aloia, Maria ULg; Tocquin, Pierre ULg; Périlleux, Claire ULg

in New Phytologist (2008), 178(4), 755-65

Of the Brassicaceae, Sinapis alba has been intensively studied as a physiological model of induction of flowering by a single long day (LD), while molecular-genetic analyses of Arabidopsis thaliana have ... [more ▼]

Of the Brassicaceae, Sinapis alba has been intensively studied as a physiological model of induction of flowering by a single long day (LD), while molecular-genetic analyses of Arabidopsis thaliana have disclosed complex interactions between pathways controlling flowering in response to different environmental cues, such as photoperiod and vernalization. The vernalization process in S. alba was therefore analysed here. The coding sequence of S. alba SaFLC, which is orthologous to the A. thaliana floral repressor FLOWERING LOCUS C, was isolated and the transcript levels quantified in different conditions. Two-week-old seedlings grown in noninductive short days (SDs) were vernalized for 1-6 wk. Down-regulation of SaFLC was already marked after 1 wk of cold but 2 wk was needed for a significant acceleration of flowering. Flower buds were initiated during vernalization. When vernalization was stopped after 1 wk, repression of SaFLC was not stable but a significant increase in plant responsiveness to 16-h LDs was observed when LDs followed immediately after the cold treatment. These results suggest that vernalization does not only work when plants experience long exposure to cold during the winter: shorter cold periods might stimulate flowering of LD plants if they occur when photoperiod is increasing, such as in spring. [less ▲]

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See detailStability of SaFLC repression in Sinapis alba. A link with quantitative effect of vernalization
D'Aloia, Maria ULg; Périlleux, Claire ULg

in Plant Signaling & Behavior (2008), 3(11), 1002-1004

In Arabidopsis thaliana, vernalization promotes flowering by repressing the floral inhibitor FLOWERING LOCUS C (AtFLC). This repression is mediated through epigenetic modifications at the AtFLC locus ... [more ▼]

In Arabidopsis thaliana, vernalization promotes flowering by repressing the floral inhibitor FLOWERING LOCUS C (AtFLC). This repression is mediated through epigenetic modifications at the AtFLC locus, leading to gene silencing. Whether the well-known quantitative effect of vernalization is due to the degree of AtFLC repression and/or its stability after return to normal temperature conditions has not been clarified. Here, we examine this question in white mustard, Sinapis alba, taking advantage of our recent cloning of the AtFLC ortholog SaFLC. [less ▲]

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See detailCloning of CONSTANS and FLOWERING LOCUS T in Sinapis alba.
Tamseddak, Karim; D'Aloia, Maria ULg; Périlleux, Claire ULg

in Comparative Biochemistry & Physiology Part A : Molecular & Integrative Physiology (2006), 143A

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See detailThe FLC-dependent vernalization pathway in Sinapis alba.
D'Aloia, Maria ULg; Tocquin, Pierre ULg; Périlleux, Claire ULg

in Comparative Biochemistry and Physiology. Part A, Physiology (2006), 143A

In many plants, flowering is promoted by a long exposure to cold, a process known as ‘vernalisation’. In Arabidopsis, the vernalisation pathway was shown to promote flowering via the repression of the ... [more ▼]

In many plants, flowering is promoted by a long exposure to cold, a process known as ‘vernalisation’. In Arabidopsis, the vernalisation pathway was shown to promote flowering via the repression of the FLOWERING LOCUS C (FLC) gene, which encodes a repressor of flowering. As far as we know, the genetical control of flowering is conserved among Brassicaceae, and we reported elsewhere cloning of flowering times genes of the photoperiodic pathway in Sinapis alba, based on sequence similarity with Arabidopsis. However, little is known about vernalisation in Sinapis. We therefore undertook a physiological and molecular study of this process. Plants of Sinapis were grown in non inductive short days and vernalised at 7°C, at the seedling stage. Vernalisation was found to accelerate flowering and an increasing effect was observed for vernalisation treatments longer than 2 weeks. We cloned an FLC-like sequence (SaFLC) by screening a cDNA library, and used it as a probe to perform expression analyses. We observed that SaFLC was almost completely repressed after 1 week of vernalisation, but repression was stable only after 2 weeks, which is consistent with the fact that 2-week is the minimal duration of vernalisation that promotes flowering. Hence the molecular mechanisms of vernalisation seem to be conserved in Sinapis and Arabidopsis. [less ▲]

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