Photosensory Adaptation in Aneural Organisms*

Galland, Paul

doi:10.1111/j.1751-1097.1991.tb02135.x

Cited by 29 publications

(17 citation statements)

References 128 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This phenomenon enables photoreceptor signaling networks to maintain a response over a broad range of light intensities (Galland, 1991;Wang and Montell, 2007). Mammalian optic organs adapt to dark and bright light conditions using rod cells that show high photosensitivity and cone cells that show low photosensitivity, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…Other members of the photoreceptor family, such as phyB, cry1, and phot2, are expressed at constant levels under bright light conditions. In addition to photoreceptors, some signal transducers functioning downstream of the photoreceptors are required for establishing light adaptation systems (Galland, 1991;Wang and Montell, 2007;Hersch et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Arabidopsis ROOT PHOTOTROPISM2 Contributes to the Adaptation to High-Intensity Light in Phototropic Responses

et al. 2015

View full text Add to dashboard Cite

Living organisms adapt to changing light environments via mechanisms that enhance photosensitivity under darkness and attenuate photosensitivity under bright light conditions. In hypocotyl phototropism, phototropin1 (phot1) blue light photoreceptors mediate both the pulse light-induced, first positive phototropism and the continuous light-induced, second positive phototropism, suggesting the existence of a mechanism that alters their photosensitivity. Here, we show that light induction of ROOT PHOTOTROPISM2 (RPT2) underlies photosensory adaptation in hypocotyl phototropism of Arabidopsis thaliana. rpt2 loss-offunction mutants exhibited increased photosensitivity to very low fluence blue light but were insensitive to low fluence blue light. Expression of RPT2 prior to phototropic stimulation in etiolated seedlings reduced photosensitivity during first positive phototropism and accelerated second positive phototropism. Our microscopy and biochemical analyses indicated that blue light irradiation causes dephosphorylation of NONPHOTOTROPIC HYPOCOTYL3 (NPH3) proteins and mediates their release from the plasma membrane. These phenomena correlate closely with the desensitization of phot1 signaling during the transition period from first positive phototropism to second positive phototropism. RPT2 modulated the phosphorylation of NPH3 and promoted reconstruction of the phot1-NPH3 complex on the plasma membrane. We conclude that photosensitivity is increased in the absence of RPT2 and that this results in the desensitization of phot1. Light-mediated induction of RPT2 then reduces the photosensitivity of phot1, which is required for second positive phototropism under bright light conditions.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Arabidopsis ROOT PHOTOTROPISM2 Contributes to the Adaptation to High-Intensity Light in Phototropic Responses

et al. 2015

View full text Add to dashboard Cite

show abstract

“…From these results, the activity of the RPT2-independent pathway seemed to be inhibited by NPH1 at a higher fluence rate than 1 mol m Ϫ2 sec Ϫ1 ( Figure 8). The effector adaptation already known in photobiology is one possibility for the inhibitory mechanism (Galland, 1991;Poff et al, 1994). Thus, the ability of the RPT2-independent pathway to transduce the signal might be saturated under the high fluence rates of blue light; therefore, the signal level between the irradiated side of the hypocotyl and the shadow side would become similar, and thus, the degree of curvature of the rpt2 mutant would decrease as the fluence rate increased.…”

Section: Adaptation Of the Phototropic Responsementioning

confidence: 99%

“…The investigation of photosensory adaptation is very important, because it reveals the light recognition mechanisms not only in Arabidopsis but also in all light-sensing organisms (Galland, 1991). In this study, we observed the limits of the fluence rate of the blue light to induce the phototropic curvature in the hypocotyls of wild-type etiolated seedlings; thus, the hypocotyl curvatures in the wild type at the fluence rate of 10 mol m Ϫ2 sec Ϫ1 decreased at the rate of 100 mol m Ϫ2 sec Ϫ1 .…”

Section: Adaptation Of the Phototropic Responsementioning

confidence: 99%

RPT2: A signal transducer of the phototropic response in Arabidopsis

Sakai¹,

Okada²

2000

Current Opinion in Plant Biology

View full text Add to dashboard Cite

The blue light receptor NPH1 (for nonphototropic hypocotyl) has been considered to be the only UV-A/blue light receptor that induces a phototropic response by the hypocotyl and root of Arabidopsis. By analysis of root phototropism ( rpt ) mutants, we show, however, the involvement of another blue light receptor as well as the existence of two separate signaling pathways working downstream of these receptors in the phototropic response. A newly isolated gene, RPT2 , controls one of these pathways. The RPT2 gene is light inducible; encodes a novel protein with putative phosphorylation sites, a nuclear localization signal, a BTB/POZ domain, and a coiled-coil domain; and belongs to a large gene family that includes the recently isolated NPH3 gene. From genetic, physiological, and biochemical evidence, we propose a genetic model of the signaling pathways that induce the phototropic response in Arabidopsis.

show abstract

“…Organisms that sense a wide range of light intensities require mechanisms of range adjustment that allow them to adapt to the changing light intensities in their environment (Galland 1991). Light activation of transcription of some genes of N. crassa is transient, transcription of these responding genes ceases after the illumination time has been extended, and further incubation in the dark is required before they are again transcribed in response to light (Lauter and Yanofsky 1993;Arpaia et al 1999;Linden 2001, 2003).…”

mentioning

confidence: 99%

A Genetic Selection For Neurospora crassa Mutants Altered in Their Light Regulation of Transcription

2008

View full text Add to dashboard Cite

Transcription of the Neurospora crassa gene con-10 is induced during conidiation and following exposure of vegetative mycelia to light, but light activation is transient due to photoadaptation. We describe mutational analyses of photoadaptation using a N. crassa strain bearing a translational fusion of con-10, including its regulatory region, to a selectable bacterial gene conferring hygromycin resistance (hph). Growth of this strain was sensitive to hygromycin, upon continuous culture in the light. Five mutants were isolated that were resistant to hygromycin when cultured under constant light. Three mutant strains displayed elevated, sustained accumulation of con-10∷hph mRNA during continued light exposure, suggesting that they bear mutations that reduce or eliminate the presumed light-dependent repression mechanism that blocks con-10 transcription upon prolonged illumination. These mutations altered photoadaptation for only a specific group of genes (con-10 and con-6), suggesting that regulation of photoadaptation is relatively gene specific. The mutations increased light-dependent mRNA accumulation for genes al-1, al-2, and al-3, each required for carotenoid biosynthesis, resulting in a threefold increase in carotenoid accumulation following continuous light exposure. Identification of the altered gene or genes in these mutants may reveal novel proteins that participate in light regulation of gene transcription in fungi.

show abstract

Photosensory Adaptation in Aneural Organisms*

Cited by 29 publications

References 128 publications

Arabidopsis ROOT PHOTOTROPISM2 Contributes to the Adaptation to High-Intensity Light in Phototropic Responses

Arabidopsis ROOT PHOTOTROPISM2 Contributes to the Adaptation to High-Intensity Light in Phototropic Responses

RPT2: A signal transducer of the phototropic response in Arabidopsis

A Genetic Selection For Neurospora crassa Mutants Altered in Their Light Regulation of Transcription

Contact Info

Product

Resources

About