Faculty Opinions recommendation of Stem-piped light activates phytochrome B to trigger light responses in Arabidopsis thaliana roots.

Abstract Ambient light controls the development and physiology of plants. The Arabidopsis thaliana photoreceptor phytochrome B (PHYB) regulates developmental light responses at both seedling and adult stages. To identify genes that mediate control of development by light, we screened for suppressors of the long hypocotyl phenotype caused by a phyB mutation. Genetic analyses show that the shy (short hypocotyl) mutations we have isolated fall in several loci. Phenotypes of the mutants suggest that some of the genes identified have functions in control of light responses. Other loci specifically affect cell elongation or expansion.

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Stem-piped light activates phytochrome B to trigger light responses in Arabidopsis thaliana roots

Science Signaling ◽

10.1126/scisignal.aaf6530 ◽

2016 ◽

Vol 9 (452) ◽

pp. ra106-ra106 ◽

Cited By ~ 66

Author(s):

H.-J. Lee ◽

J.-H. Ha ◽

S.-G. Kim ◽

H.-K. Choi ◽

Z. H. Kim ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Phytochrome B ◽

Light Responses

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Analysis of the Function of the Photoreceptors Phytochrome B and Phytochrome D in Nicotiana plumbaginifolia and Arabidopsis thaliana

Plant and Cell Physiology ◽

10.1093/pcp/pci073 ◽

2005 ◽

Vol 46 (5) ◽

pp. 790-796 ◽

Cited By ~ 8

Author(s):

Aurora Piñas Fernández ◽

Patricia Gil ◽

Ildiko Valkai ◽

Ferenc Nagy ◽

Eberhard Schäfer

Keyword(s):

Arabidopsis Thaliana ◽

Nicotiana Plumbaginifolia ◽

Phytochrome B

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Direct photoresponsive inhibition of a p53-like transcription activation domain in PIF3 by Arabidopsis phytochrome B

10.1101/2021.05.11.443493 ◽

2021 ◽

Author(s):

Chan Yul Yoo ◽

Qing Sang ◽

Jiangman He ◽

Yongjian Qiu ◽

Lingyun Long ◽

...

Keyword(s):

Transcription Factors ◽

Target Genes ◽

Transcription Activation ◽

Phytochrome B ◽

Activation Domain ◽

Light Responses ◽

Dark Light ◽

Transactivation Activity ◽

Transcription Activation Domain

Phytochrome B (PHYB) triggers diverse light responses in Arabidopsis by binding to a group of antagonistically acting PHYTOCHROME-INTERACTING transcription FACTORs (PIFs) to promote PIF degradation, consequently downregulating PIF target genes. However, whether PHYB directly controls the transactivation activity of PIFs remains ambiguous. Here we show that the prototypic PIF, PIF3, possesses a p53-like transcription activation domain (TAD) consisting of a sequence-specific, hydrophobic activator motif surrounded by acidic residues. A PIF3mTAD mutant in which the activator motif is replaced with alanines fails to activate PIF3 target genes in Arabidopsis in dark, light, and shade conditions, validating the in vivo functions of the PIF3 TAD. Intriguingly, binding of the N-terminal photosensory module of PHYB to the PHYB-binding site adjacent to the TAD inhibits its transactivation activity. These results unveil a photoresponsive transcriptional switching mechanism in which photoactivated PHYB directly masks the transactivation activity of PIF3. Our study also suggests the unexpected conservation of sequence-specific TADs between the animal and plant kingdoms.

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Phytochrome A and phytochrome B regulate the biosynthesis of chlorophyll during cytokinin-dependent de-etiolation of Arabidopsis thaliana

Plant Genetics, Genomics, Bioinformatics, and Biotechnology (PlantGen2021) ◽

10.18699/plantgen2021-129 ◽

2021 ◽

Keyword(s):

Arabidopsis Thaliana ◽

Phytochrome B ◽

Phytochrome A

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Light Gradient-Based Screening of Arabidopsis thaliana on a 384-Well Type Plant Array Chip

Micromachines ◽

10.3390/mi11020191 ◽

2020 ◽

Vol 11 (2) ◽

pp. 191

Author(s):

Youn-Hee Park ◽

Je-Kyun Park

Keyword(s):

Arabidopsis Thaliana ◽

White Light ◽

Solid Medium ◽

Red Light ◽

Phytochrome B ◽

Wild Type ◽

Light Gradient ◽

Gradient Based ◽

Light Effects ◽

Germination And Growth

Arabidopsis thaliana (Arabidopsis), as a model for plant research, is widely used for various aspects of plant science. To provide a more sophisticated and microscopic environment for the germination and growth of Arabidopsis, we report a 384-well type plant array chip in which each Arabidopsis seed is independently seeded in a solid medium. The plant array chip is made of a poly(methyl methacrylate) (PMMA) acrylic material and is assembled with a home-made light gradient module to investigate the light effects that significantly affect the germination and growth of Arabidopsis. The light gradient module was used to observe the growth pattern of seedlings according to the intensity of the white light and to efficiently screen for the influence of the white light. To investigate the response to red light (600 nm), which stimulates seed germination, the light gradient module was also applied to the germination test. As a result, the germination results showed that the plant array chip can be used to simultaneously screen wild type seeds and phytochrome B mutant seeds on a single array chip according to the eight red light intensities.

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Arabidopsis chloroplast J protein DJC75/CRRJ mediates nitrate-promoted seed germination in the dark

Annals of Botany ◽

10.1093/aob/mcaa040 ◽

2020 ◽

Vol 125 (7) ◽

pp. 1091-1099

Author(s):

Huai-Syuan Ciou ◽

Yu-Lun Tsai ◽

Chi-Chou Chiu

Keyword(s):

Arabidopsis Thaliana ◽

Seed Germination ◽

Germination Rate ◽

Red Light ◽

Phytochrome B ◽

Biosynthetic Gene ◽

Unknown Mechanism ◽

J Domain ◽

Domain Protein ◽

J Protein

Abstract Background and Aims Nitrate can stimulate seed germination of many plant species in the absence of light; however, the molecular mechanism of nitrate-promoted seed germination in the dark remains largely unclear and no component of this pathway has been identified yet. Here, we show that a plastid J-domain protein, DJC75/CRRJ, in arabidopsis (Arabidopsis thaliana) is important for nitrate-promoted seed germination in the dark. Methods The expression of DJC75 during imbibition in the dark was investigated. The seed germination rate of mutants defective in DJC75 was determined in the presence of nitrate when light cues for seed germination were eliminated by the treatment of imbibed seeds with a pulse of far-red light to inactivate phytochrome B (phyB), or by assaying germination in the dark with seeds harbouring the phyB mutation. The germination rates of mutants defective in CRRL, a J-like protein related to DJC75, and in two chloroplast Hsp70s were also measured in the presence of nitrate in darkness. Key Results DJC75 was expressed during seed imbibition in the absence of light. Mutants defective in DJC75 showed seed germination defects in the presence of nitrate when light cues for seed germination were eliminated. Mutants defective in CRRL and in two chloroplast Hsp70s also exhibited similar seed germination defects. Upregulation of gibberellin biosynthetic gene GA3ox1 expression by nitrate in imbibed phyB mutant seeds was diminished when DJC75 was knocked out. Conclusions Our data suggest that plastid J-domain protein DJC75 regulates nitrate-promoted seed germination in the dark by upregulation of expression of the gibberellin biosynthetic gene GA3ox1 through an unknown mechanism and that DJC75 may work in concert with chloroplast Hsp70s to regulate nitrate-promoted seed germination. DJC75 is the first pathway component identified for nitrate-promoted seed germination in the dark.

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