The Negatively Acting Factors EID1 and SPA1 Have Distinct Functions in Phytochrome A-Specific Light Signaling

Zhou, Yingqiu; Dieterle, Monika; Büche, Claudia; Kretsch, Thomas

doi:10.1104/pp.010811

Cited by 35 publications

(42 citation statements)

References 36 publications

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“…The phenotypic effects of spa1 mutations are dependent on a functional PHYA gene, suggesting that SPA1 is important for normal phyA signaling (Hoecker et al, 1998). Moreover, spa1 mutations enhance both modes of phyA action, the response to FRc and the very low fluence response (Baumgardt et al, 2002;Zhou et al, 2002). It was also suggested that growth promotion by SPA1 counteracts phytochromemediated growth inhibition in hypocotyls (Parks et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

The SPA Quartet: A Family of WD-Repeat Proteins with a Central Role in Suppression of Photomorphogenesis in Arabidopsis

Laubinger¹,

Fittinghoff²,

Hoecker³

2004

Plant Cell

207

326

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The Arabidopsis thaliana proteins suppressor of phytochrome A-105 1 (SPA1), SPA3, and SPA4 of the four-member SPA1 protein family have been shown to repress photomorphogenesis in light-grown seedlings. Here, we demonstrate that spa quadruple mutant seedlings with defects in SPA1, SPA2, SPA3, and SPA4 undergo strong constitutive photomorphogenesis in the dark. Consistent with this finding, adult spa quadruple mutants are extremely small and dwarfed. These extreme phenotypes are only observed when all SPA genes are mutated, indicating functional redundancy among SPA genes. Differential contributions of individual SPA genes were revealed by analysis of spa double and triple mutant genotypes. SPA1 and SPA2 predominate in dark-grown seedlings, whereas SPA3 and SPA4 prevalently regulate the elongation growth in adult plants. Further analysis of SPA2 function indicated that SPA2 is a potent repressor of photomorphogenesis only in the dark but not in the light. The SPA2 protein is constitutively nuclear localized in planta and can physically interact with the repressor COP1. Epistasis analysis between spa2 and cop1 mutations provides strong genetic support for a biological significance of a COP1-SPA2 interaction in the plant. Taken together, our results have identified a new family of proteins that is essential for suppression of photomorphogenesis in darkness.

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Section: Introductionmentioning

confidence: 99%

The SPA Quartet: A Family of WD-Repeat Proteins with a Central Role in Suppression of Photomorphogenesis in Arabidopsis

Laubinger¹,

Fittinghoff²,

Hoecker³

2004

Plant Cell

207

326

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“…Several of our observations clearly indicate that the mutation in the HA subdomain has very severe influences on light signal transduction events related to EID1, which functions as an important negative regulator in phyA-dependent HIR signaling (Bü che et al, 2000;Dieterle et al, 2001;Zhou et al, 2002;Marrocco et al, 2006). First, the phyA-402 mutation robustly suppresses the effects of the strong allele eid1-3 under continuous far-red and weak red light, even though it does not severely affect light sensitivity in the wild type under the same light conditions (Figs.…”

Section: Discussionmentioning

confidence: 99%

“…The phyA-402 Mutation Causes a Shift in Spectral Sensitivity and Persistence of HIR Because EID1 functions as an important negative regulator in far-red HIR (Bü che et al, 2000;Dieterle et al, 2001, Zhou et al, 2002Marrocco et al, 2006), it was quite astonishing that the wild type and phyA-402 exhibited nearly identical fluence rate dependencies for inhibition of hypocotyl elongation and for anthocyanin accumulation. To search for more subtle influences of phyA-402 on far-red HIR, additional fluence rate response curves were measured for seedlings irradiated with narrow-banded interference filters in order to construct an action spectrum for hypocotyl elongation (Supplemental Fig.…”

Section: Physiological Characterization Of Phya-402mentioning

confidence: 99%

“…The action spectra of HIRs show a maximum at approximately 720 nm, a wavelength that establishes high levels of Pr and inhibits responses of lightstable phytochrome. Furthermore, the magnitude of HIRs depends not only on the duration and fluence rate of far-red light irradiation but can be halted by short dark periods (Mancinelli, 1994;Bü che et al, 2000;Dieterle et al, 2001Dieterle et al, , 2005Zhou et al, 2002).…”

mentioning

confidence: 99%

“…EID1 (for EMPFINDLICHER IM DUNKELROTEN LICHT1) is an F-box protein that functions as a negative regulator in phyA-specific light signaling (Bü che et al, 2000;Dieterle et al, 2001;Zhou et al, 2002;Marrocco et al, 2006). The protein most probably functions as a component of a ubiquitin ligase complex that degrades positively acting phyA signaling factors.…”

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confidence: 99%

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The Histidine Kinase-Related Domain of Arabidopsis Phytochrome A Controls the Spectral Sensitivity and the Subcellular Distribution of the Photoreceptor

et al. 2009

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Phytochrome A (phyA) is the primary photoreceptor for sensing extremely low amounts of light and for mediating various farred light-induced responses in higher plants. Translocation from the cytosol to the nucleus is an essential step in phyA signal transduction. EID1 (for EMPFINDLICHER IM DUNKELROTEN LICHT1) is an F-box protein that functions as a negative regulator in far-red light signaling downstream of the phyA in Arabidopsis (Arabidopsis thaliana). To identify factors involved in EID1-dependent light signal transduction, pools of ethylmethylsulfonate-treated eid1-3 seeds were screened for seedlings that suppress the hypersensitive phenotype of the mutant. The phenotype of the suppressor mutant presented here is caused by a missense mutation in the PHYA gene that leads to an amino acid transition in its histidine kinase-related domain. The novel phyA-402 allele alters the spectral sensitivity and the persistence of far-red light-induced high-irradiance responses. The strong eid1-3 suppressor phenotype of phyA-402 contrasts with the moderate phenotype observed when phyA-402 is introgressed into the wild-type background, which indicates that the mutation mainly alters functions in an EID1-dependent signaling cascade. The mutation specifically inhibits nuclear accumulation of the photoreceptor molecule upon red light irradiation, even though it still interacts with FHY1 (for far-red long hypocotyl 1) and FHL (for FHY1-like protein), two factors that are essential for nuclear accumulation of phyA. Degradation of the mutated phyA is unaltered even under light conditions that inhibit its nuclear accumulation, indicating that phyA degradation may occur mostly in the cytoplasm.

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Phenotypic Characterization of Photomorphogenic Responses During Plant Development

Kretsch

2010

Plant Developmental Biology

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Light is one of the most important exogenous factors regulating plant development throughout the entire life cycle. Light is involved in the breaking of seed dormancy, the regulation of photomorphogenic seedling development, the adaptation of plant morphology toward spectral composition of incident light, and the transition to flowering. Plants have evolved with several photoreceptor families that sense UV-A, blue, red, and far-red light. Here, basal methods to measure light-regulated changes in plant morphology and pigment accumulation will be described. The methods include the determination of apical hook angle and cotyledon opening, the measurement of stem elongation, the determination of leaf surface area, the measurements that characterize light-controlled transition to flowering, and the determination of anthocyanin and chlorophyll accumulation. Furthermore, different light programs are listed that can be used to test for the functional involvement of separate light response modes controlling photomorphogenic plant development.

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The Negatively Acting Factors EID1 and SPA1 Have Distinct Functions in Phytochrome A-Specific Light Signaling

Cited by 35 publications

References 36 publications

The SPA Quartet: A Family of WD-Repeat Proteins with a Central Role in Suppression of Photomorphogenesis in Arabidopsis

The SPA Quartet: A Family of WD-Repeat Proteins with a Central Role in Suppression of Photomorphogenesis in Arabidopsis

The Histidine Kinase-Related Domain of Arabidopsis Phytochrome A Controls the Spectral Sensitivity and the Subcellular Distribution of the Photoreceptor

Phenotypic Characterization of Photomorphogenic Responses During Plant Development

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