Two Distinct Blue-Light Responses Regulate Epicotyl Elongation in Pea

Warpeha, Katherine M.; Kaufman, Lon S.

doi:10.1104/pp.92.2.495

Cited by 25 publications

(14 citation statements)

References 13 publications

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“…Fluence levels used have been confirmed to be within reciprocity limits (Warpeha & Kaufman 1990a). Aerial portions were subsequently harvested to conduct experiments as described.…”

Section: Plant Growth and Preparation Of Tissuementioning

confidence: 99%

Adequate phenylalanine synthesis mediated by G protein is critical for protection from UV radiation damage in young etiolated Arabidopsis thaliana seedlings

Warpeha

Gibbons

Carol

et al. 2008

Plant Cell & Environment

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Etiolated Arabidopsis thaliana seedlings, lacking a functional prephenate dehydratase1 gene (PD1), also lack the ability to synthesize phenylalanine (Phe) and, as a consequence, phenylpropanoid pigments. We find that low doses of ultraviolet (UV)-C (254 nm) are lethal and low doses of UV-B cause severe damage to etiolated pd1 mutants, but not to wild-type (wt) seedlings. Furthermore, exposure to UV-C is lethal to etiolated gcr1 (encoding a putative G proteincoupled receptor in Arabidopsis) mutants and gpa1 (encoding the sole G protein a subunit in Arabidopsis) mutants. Addition of Phe to growth media restores wt levels of UV resistance to pd1 mutants. The data indicate that the Arabidopsis G protein-signalling pathway is critical to providing protection from UV, and does so via the activation of PD1, resulting in the synthesis of Phe. Cotyledons of etiolated pd1 mutants have proplastids (compared with etioplasts in wt), less cuticular wax and fewer long-chain fatty acids. Phederived pigments do not collect in the epidermal cells of pd1 mutants when seedlings are treated with UV, particularly at the cotyledon tip. Addition of Phe to the growth media restores a wt phenotype to pd1 mutants.

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“…Fluence levels used have been confirmed to be within reciprocity limits (Warpeha & Kaufman 1990a). Aerial portions were subsequently harvested to conduct experiments as described.…”

Section: Plant Growth and Preparation Of Tissuementioning

confidence: 99%

Adequate phenylalanine synthesis mediated by G protein is critical for protection from UV radiation damage in young etiolated Arabidopsis thaliana seedlings

Warpeha

Gibbons

Carol

et al. 2008

Plant Cell & Environment

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“…BL irradiation materials have been described in full (Warpeha and Kaufman, 1990a). Anthocyanins were extracted and quantified according to Noh and Spalding (1998).…”

Section: Amino Acid Analysismentioning

confidence: 99%

G-Protein-Coupled Receptor 1, G-Protein Gα-Subunit 1, and Prephenate Dehydratase 1 Are Required for Blue Light-Induced Production of Phenylalanine in Etiolated Arabidopsis

et al. 2006

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Different classes of plant hormones and different wavelengths of light act through specific signal transduction mechanisms to coordinate higher plant development. A specific prephenate dehydratase protein (PD1) was discovered to have a strong interaction with the sole canonical G-protein Gα-subunit (GPA1) in Arabidopsis (Arabidopsis thaliana). PD1 is a protein located in the cytosol, present in etiolated seedlings, with a specific role in blue light-mediated synthesis of phenylpyruvate and subsequently of phenylalanine (Phe). Insertion mutagenesis confirms that GPA1 and the sole canonical G-protein-coupled receptor (GCR1) in Arabidopsis also have a role in this blue light-mediated event. In vitro analyses indicate that the increase in PD1 activity is the direct and specific consequence of its interaction with activated GPA1. Because of their shared role in the light-mediated synthesis of phenylpyruvate and Phe, because they are iteratively interactive, and because activated GPA1 is directly responsible for the activation of PD1; GCR1, GPA1, and PD1 form all of or part of a signal transduction mechanism responsible for the light-mediated synthesis of phenylpyruvate, Phe, and those metabolites that derive from that Phe. Data are also presented to confirm that abscisic acid can act through the same pathway. An additional outcome of the work is the confirmation that phenylpyruvate acts as the intermediate in the synthesis of Phe in etiolated plants, as it commonly does in bacteria and fungi.

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“…In light of such results they hypothesized that the mechanism allowing the protoplast shrinking response mediates the blue lightinduced growth inhibition. The growth of pea stems is inhibited by blue light (Laskowski and Briggs, 1989;Warpeha and Kaufman, 1990). Laskowski and Briggs (1989) could resolve a rapid blue lightinduced growth inhibition in R-grown pea seedlings.…”

Section: ؉ Uptake As a Step Of Phytochrome Signal Transductionmentioning

confidence: 99%

Light-Dependent Osmoregulation in Pea Stem Protoplasts. Photoreceptors, Tissue Specificity, Ion Relationships, and Physiological Implications

Ling

Iino

2001

Plant Physiology

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Light-induced changes in the volume of protoplasts bathed in a medium of constant osmolarity are useful indications of light-dependent cellular osmoregulation. With this in mind, we investigated the effect of light on the volume of protoplasts isolated from the elongating stems of pea (Pisum sativum) seedlings raised under red light. The protoplasts were isolated separately from epidermal peels and the remaining peeled stems. Under continuous red light, the protoplasts of peeled stems swelled steadily, but those of epidermal peels maintained a constant volume. Experiments employing far-red light and phytochrome-deficient mutants revealed that the observed swelling is a light-induced response mediated mainly by phytochromes A and B with a little greater contribution by phytochrome A. Protoplasts of epidermal peels and peeled stems shrank transiently in response to a pulse of blue light. The blue light responsiveness in this shrinking response, which itself is probably mediated by cryptochrome, is under the strict control of phytochromes A and B with equal contributions by these phytochromes. We suggest that the swelling response participates in the maintenance of high tissue tension of elongating stems and that the shrinking response is involved in stem growth inhibition. Other findings include the following: The swelling is caused by uptake of K+ and Cl−. The presence of Ca2+in the bathing medium is required for phytochrome signaling in the swelling response, but not in the response establishing blue light responsiveness. Phytochrome A mediates the two responses in a totally red/far-red light reversible manner, as does phytochrome B.

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Two Distinct Blue-Light Responses Regulate Epicotyl Elongation in Pea

Cited by 25 publications

References 13 publications

Adequate phenylalanine synthesis mediated by G protein is critical for protection from UV radiation damage in young etiolated Arabidopsis thaliana seedlings

Adequate phenylalanine synthesis mediated by G protein is critical for protection from UV radiation damage in young etiolated Arabidopsis thaliana seedlings

G-Protein-Coupled Receptor 1, G-Protein Gα-Subunit 1, and Prephenate Dehydratase 1 Are Required for Blue Light-Induced Production of Phenylalanine in Etiolated Arabidopsis

Light-Dependent Osmoregulation in Pea Stem Protoplasts. Photoreceptors, Tissue Specificity, Ion Relationships, and Physiological Implications

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