scholarly journals Genetic Interactions between Phytochrome A, Phytochrome B, and Cryptochrome 1 during Arabidopsis Development

1998 ◽  
Vol 118 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Michael M. Neff ◽  
Joanne Chory
Keyword(s):  
Genetic Interactions ◽  
Phytochrome B ◽  
Phytochrome A ◽  
Cryptochrome 1

Hierarchical coupling of phytochromes and cryptochromes reconciles stability and light modulation of Arabidopsis development

Development ◽  
2001 ◽  
Vol 128 (12) ◽  
pp. 2291-2299
Author(s):  
María Agustina Mazzella ◽  
Pablo D. Cerdán ◽  
Roberto J. Staneloni ◽  
Jorge J. Casal
Keyword(s):  
Phytochrome B ◽  
Light Modulation ◽  
Phytochrome A ◽  
Hypocotyl Growth ◽  
Triple Mutant ◽  
Leaf Production ◽  
Developmental Processes ◽  
Cryptochrome 2 ◽  
Delayed Flowering ◽  
Cryptochrome 1

In plants, development is a continuing process that takes place under strong fluctuations of the light environment. Here we show that in Arabidopsis thaliana plants grown under intense white light, coupling of the photoreceptor cryptochrome 2 to developmental processes is broader than previously appreciated. Compared to the wild type, the cry2 mutant showed reduced activity of a Lhcb1*2 promoter fused to a reporter, and delayed flowering. The cry2 mutation also reduced the inhibition of hypocotyl growth, the unfolding of the cotyledons, the rate of leaf production during the vegetative phase, and the pace of development after transition to the reproductive stage; but these effects were obvious only in the absence of cryptochrome 1 and in some cases phytochrome A and/or phytochrome B. Complementary, the cry2 mutation uncovered novel roles for cryptochrome 1 and phytochrome A. The activity of the Lhcb1*2 promoter was higher in the cry1 cry2 mutant than in the cry2 mutant, suggesting that cry1 could be involved in blue-light repression of photosynthetic genes. Surprisingly, the phyA cry1 cry2 triple mutant flowered earlier and showed better response to photoperiod than the cry1 cry2 double mutant, indicating that phyA is involved in light repression of flowering. Growth and development were severely impaired in the quadruple phyA phyB cry1 cry2 mutant. We propose that stability and light modulation of development are achieved by simultaneous coupling of phytochrome A, phytochrome B, cryptochrome 1 and cryptochrome 2 to developmental processes, in combination with context-dependent hierarchy of their relative activities.

Cryptochrome 1, Cryptochrome 2, and Phytochrome A Co-Activate the Chloroplast psbD Blue Light-Responsive Promoter

2001 ◽  
Vol 13 (12) ◽  
pp. 2747
Author(s):  
Karen E. Thum ◽  
Minkyun Kim ◽  
David A. Christopher ◽  
John E. Mullet
Keyword(s):  
Blue Light ◽  
Phytochrome A ◽  
Cryptochrome 2 ◽  
Cryptochrome 1

scholarly journals Cryptochrome 1, Cryptochrome 2, and Phytochrome A Co-Activate the Chloroplast psbD Blue Light–Responsive Promoter

2001 ◽  
Vol 13 (12) ◽  
pp. 2747-2760
Author(s):  
Karen E. Thum ◽  
Minkyun Kim ◽  
David A. Christopher ◽  
John E. Mullet
Keyword(s):  
Blue Light ◽  
Phytochrome A ◽  
Cryptochrome 2 ◽  
Cryptochrome 1

Phytochromes and seed germination

1998 ◽  
Vol 8 (3) ◽  
pp. 317-329 ◽  
Author(s):  
Jorge J. Casal ◽  
Rodolfo A. Sánchez
Keyword(s):  
Seed Germination ◽  
Red Light ◽  
High Irradiance ◽  
Phytochrome B ◽  
Phytochrome A ◽  
Germination Inhibition ◽  
Growth Capacity ◽  
Small Family ◽  
Recent Advances ◽  
Signalling Process

AbstractThe control of seed germination by red and far-red light is one of the earliest documented phytochrome-mediated processes Phytochrome is now known to be a small family of photoreceptors whose apoproteins are encoded by different genes Phytochrome B (phyB) is present in dry seeds and affects germination of dark imbibed seeds but other phytochromes could also be involved Phytochrome A (phyA) appears after several hours of imbibition and mediates very-low-fluence responses PhyB and other phytochromes different from phyA mediate the classical low-fluence responses The phytochrome involved in high-irradiance responses of seed germination (inhibition of germination under continuous far-red) has not been unequivocally established, although phyA is the most likely candidate Phytochrome can affect embryo growth capacity and/or the constraint imposed by the tissues surrounding the embryo At least in some species, gibberellins participate in the signalling process In the field, phyA has been implicated in the perception of light during soil cultivations, and phyB would be involved in the perception of red/far-red ratios associated with the presence of gaps in the canopy This review describes recent advances in phytochrome research, particularly those derived from the analysis of germination in specific mutants, and their connection with traditional observations on phytochrome control of seed germination

scholarly journals Sustained but Not Transient Phytochrome A Signaling Targets a Region of an Lhcb1*2 Promoter Not Necessary for Phytochrome B Action

2000 ◽  
Vol 12 (7) ◽  
pp. 1203-1211 ◽  
Author(s):  
Pablo D. Cerdán ◽  
Roberto J. Staneloni ◽  
Jimena Ortega ◽  
Matilde M. Bunge ◽  
María J. Rodriguez-Batiller ◽  
...  
Keyword(s):  
Phytochrome B ◽  
Phytochrome A
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