The <i>Arabidopsis</i> E3 Ubiquitin Ligase HOS1 Negatively Regulates CONSTANS Abundance in the Photoperiodic Control of Flowering

Lázaro, A. M.; Valverde, Federico; Piñeiro, Manuel; Jarillo, José A.

doi:10.1105/tpc.110.081885

Cited by 211 publications

(284 citation statements)

References 86 publications

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“…In addition to COP1 and FKF1 that were discussed above, HOS1 and TOE1 have also been implicated in regulating CO stability (Lazaro et al , 2012; Zhang et al , 2015). Although it is possible that HOS1 and TOE1 might also be regulated by PRRs, our genetic data with the cop1 toc1 prr5 prr7 prr9 quintuple mutant do not currently support this hypothesis, because the cop1 mutation is epistatic to the prr mutations with respect to CO protein abundance (Fig 4E and F).…”

Section: Discussionmentioning

confidence: 99%

PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length

et al. 2017

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Seasonal reproduction in many organisms requires detection of day length. This is achieved by integrating information on the light environment with an internal photoperiodic time‐keeping mechanism. Arabidopsis thaliana promotes flowering in response to long days (LDs), and CONSTANS (CO) transcription factor represents a photoperiodic timer whose stability is higher when plants are exposed to light under LDs. Here, we show that PSEUDO RESPONSE REGULATOR (PRR) proteins directly mediate this stabilization. PRRs interact with and stabilize CO at specific times during the day, thereby mediating its accumulation under LDs. PRR‐mediated stabilization increases binding of CO to the promoter of FLOWERING LOCUS T (FT), leading to enhanced FT transcription and early flowering under these conditions. PRRs were previously reported to contribute to timekeeping by regulating CO transcription through their roles in the circadian clock. We propose an additional role for PRRs in which they act upon CO protein to promote flowering, directly coupling information on light exposure to the timekeeper and allowing recognition of LDs.

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Section: Discussionmentioning

confidence: 99%

PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length

et al. 2017

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“…In this process, PHYTOCHROME-DEPENDENT LATE FLOWERING (PHL) interacts with both phyB and CO, and prevents phyB-mediated degradation of CO (Endo et al, 2013). HOS1, a ring domain-containing E3 ligase destabilizes during the day (Lazaro et al, 2012). ZTL and LKP2 promote degradation of CO in the morning, whereas FKF1 stabilizes CO by direct interaction (Song et al, 2014(Song et al, , 2012.…”

Section: Introductionmentioning

confidence: 99%

NO FLOWERING IN SHORT DAY (NFL) is a bHLH transcription factor that promotes flowering specifically under short-day in Arabidopsis

et al. 2016

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Flowering in plants is a dynamic and synchronized process where various cues including age, day length, temperature and endogenous hormones fine-tune the timing of flowering for reproductive success. Arabidopsis thaliana is a facultative long day (LD) plant where LD photoperiod promotes flowering. Arabidopsis still flowers under shortday (SD) conditions, albeit much later than in LD conditions. Although factors regulating the inductive LD pathway have been extensively investigated, the non-inductive SD pathway is much less understood. Here, we identified a key basic helix-loop-helix transcription factor called NFL (NO FLOWERING IN SHORT DAY) that is essential to induce flowering specifically under SD conditions in Arabidopsis. nfl mutants do not flower under SD conditions, but flower similar to the wild type under LD conditions. The no-flowering phenotype in SD is rescued either by exogenous application of gibberellin (GA) or by introducing della quadruple mutants in the nfl background, suggesting that NFL acts upstream of GA to promote flowering. NFL is expressed at the meristematic regions and NFL is localized to the nucleus. Quantitative RT-PCR assays using apical tissues showed that GA biosynthetic genes are downregulated and the GA catabolic and receptor genes are upregulated in the nfl mutant compared with the wild type, consistent with the perturbation of the endogenous GA biosynthetic and catabolic intermediates in the mutant. Taken together, these data suggest that NFL is a key transcription factor necessary for promotion of flowering under non-inductive SD conditions through the GA signaling pathway.

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“…For instance, HOS1 negatively regulates auxin biosynthesis in the control of hypocotyl elongation. 27 It has been previously reported that hos1 mutants show reduced leaf area, 28 although underlying molecular mechanism is elusive. Thus, we wanted to know how HOS1 regulates leaf expansion.…”

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confidence: 99%

The E3 ubiquitin ligase HOS1 is involved in ethylene regulation of leaf expansion inArabidopsis

Lee

Seo

2015

Plant Signaling & Behavior

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Ethylene regulates a variety of physiological processes, such as flowering, senescence, abscission, and fruit ripening. In particular, leaf expansion is also controlled by ethylene in Arabidopsis. Exogenous treatment with ethylene inhibits leaf expansion, and consistently, ethylene insensitive mutants show increased leaf area. Here, we report that the RING finger-containing E3 ubiquitin ligase HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1 (HOS1) regulates leaf expansion in an ethylene signaling pathway. The HOS1-deficient mutant showed reduced leaf area and was insensitive to ethylene perception inhibitor, silver thiosulfate (STS). Accordingly, genes encoding ethylene signaling components were significantly up-regulated in hos1-3. This study demonstrates that the HOS1 protein is involved in ethylene signal transduction for the proper regulation of leaf expansion possibly under environmentally stressful conditions.Leaf expansion is a crucial process that not only determines the shape and size of mature leaves but also ensures its photosynthetic capacity for plant growth and development. 1,2 It is influenced by multiplicity of environmental factors, such as water availability and day length. 3,4 In addition, endogenous hormone signaling is also intensively involved in the control of leaf expansion. Promotive roles of auxin, brassinosteroid, and gibberellin in leaf expansion have been demonstrated. [5][6][7] The simple hydrocarbon ethylene is a gaseous plant hormone that regulates a variety of developmental processes, such as seed germination, cell elongation, abscission, senescence, sex determination, and fruit ripening. [8][9][10][11][12][13] It has been also proposed that ethylene negatively regulates leaf expansion process. Exogenous ethylene treatment results in reduced leaf area. 14 Furthermore, ethylene insensitive mutants, such as ethylene receptor 1 (etr1) and ethylene response sensor 1 (ers1), show increased leaf size. 15,16 Five receptor isoforms are responsible for ethylene perception: ETR1, ETR2, ERS1, ERS2, and ETHYLENE INSENSITIVE 4 (EIN4). 17 Their ethylene perception is integrated into a negative regulator of ethylene signaling, CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1) Ser/Thr protein kinase, 18 which in turn regulates a series of transcriptional cascades in order to control ethylene-dependent physiological processes. EIN2 is a representative positive signaling regulator and subsequently activates genes encoding EIN3 and related EIN3-LIKE (EIL), which further regulate expression of ETHYLENE-RESPONSE FACTORs (ERFs). 19,20 In the presence of ethylene, ethylene receptors inactivate kinase activity of CTR1 so that subsequent transcriptional cascades are activated. 21 Although ethylene signaling pathways have been intensively investigated, its intricate networks with other signaling pathways remain to be unraveled.The RING-type E3 ligase HOS1 was originally reported as cold signaling attenuator. 22 The cold-activated HOS1 protein executes protein turnover of the INDUCER OF CBF EXPRESSION1 (ICE1) MYC-l...

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The Arabidopsis E3 Ubiquitin Ligase HOS1 Negatively Regulates CONSTANS Abundance in the Photoperiodic Control of Flowering

Cited by 211 publications

References 86 publications

PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length

PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length

NO FLOWERING IN SHORT DAY (NFL) is a bHLH transcription factor that promotes flowering specifically under short-day in Arabidopsis

The E3 ubiquitin ligase HOS1 is involved in ethylene regulation of leaf expansion inArabidopsis

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