High-and low-intensity photosystems in Phycomyces phototropism: Effects of mutations in genes madA, madB, and madC

A. Palit, P. Galland, E. D. Lipson

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Sporangiophores of Phycomyces blakesleeanus Burgeff that have been grown in darkness and are then suddenly exposed to unilateral light show a two-step bending response rather than a smooth, monotonic response found in light-adapted specimens (Galland and Lipson, 1987, Proc. Natl. Acad. Sci. USA 84, 104-108). The stepwise bending is controlled by two photosystems optimized for the low-and high-intensity ranges. These two photosystems have now been studied in phototropism mutants with defects in genes madA, madB, and madC. All three mutations raise the threshold of the low-intensity (low-fluence) photosystem by about 106-fold and that of the high-intensity (high-fluence) system by about 103-fold. Estimates for the light-adaptation time constants of the low-and high-intensity photosystems show that the mutants are affected in adaptation. In the mutants, the light-adaptation kinetics are only slightly affected in the low-intensity photosystem but, for the high-intensity photosystem, the kinetics are considerably slower than in the wild type.

Original languageEnglish (US)
Pages (from-to)547-553
Number of pages7
JournalPlanta
Volume177
Issue number4
DOIs
StatePublished - Apr 1989

Fingerprint

Phototropism
Phycomyces
Ocular Adaptation
phototropism
mutation
Light
Mutation
Darkness
mutants
Genes
genes
Phycomyces blakesleeanus
kinetics

Keywords

  • Mutant, behavioral (Phycomyces)
  • Photoreceptor (phototropism)
  • Phototropism (Phycomyces)
  • Phycomyces

ASJC Scopus subject areas

  • Plant Science

Cite this

High-and low-intensity photosystems in Phycomyces phototropism : Effects of mutations in genes madA, madB, and madC. / Palit, A.; Galland, P.; Lipson, E. D.

In: Planta, Vol. 177, No. 4, 04.1989, p. 547-553.

Research output: Contribution to journalArticle

Palit, A. ; Galland, P. ; Lipson, E. D. / High-and low-intensity photosystems in Phycomyces phototropism : Effects of mutations in genes madA, madB, and madC. In: Planta. 1989 ; Vol. 177, No. 4. pp. 547-553.
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