Seed germination of Arabidopsis thaliana phyA/phyB double mutants is under phytochrome control.
AUTOR(ES)
Poppe, C
RESUMO
We examined the photocontrol of seed germination in the phyA/phyB double mutants of Arabidopsis thaliana seeds. Dormant phyA/phyB seeds showed a red/far-red light (R/FR)-reversible induction of seed germination. This suggests the involvement of at least one other phytochrome, phyC, D, and/or E, in controlling seed germination. We designated this spectrally active phytochrome in phyA/phyB as phyX. The full reversibility of the R-induced germination by subsequent FR pulses, and the observation that the response is reversible by FR, even after a 3-h R treatment, indicates that this phyX response belongs to the low-fluence-response type. Thus, this phyX response is functionally related to phyB-mediated responses. However, in contrast to phyB-controlled seed germination, this phyX-mediated response needs a prolonged imbibition period and exhibits reversibility kinetics different from that needed for phyB. Furthermore, this phyX response requires a prolonged irradiation time and shows a fluence rate response dependency, showing a similarity to the high irradiance response of photomorphogenesis. Thus, phyX, with regard to its control of seed germination, is a functionally new phytochrome that shares some characteristics of both phyA- and phyB-mediated responses.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=158442Documentos Relacionados
- The Induction of Seed Germination in Arabidopsis thaliana Is Regulated Principally by Phytochrome B and Secondarily by Phytochrome A.
- Action spectra for phytochrome A- and B-specific photoinduction of seed germination in Arabidopsis thaliana.
- Conditional Synergism between Cryptochrome 1 and Phytochrome B Is Shown by the Analysis of phyA, phyB, and hy4 Simple, Double, and Triple Mutants in Arabidopsis
- Mutants of Arabidopsis thaliana Capable of Germination under Saline Conditions.
- PIL5, a Phytochrome-Interacting Basic Helix-Loop-Helix Protein, Is a Key Negative Regulator of Seed Germination in Arabidopsis thalianaW⃞