Possible involvement of a tetrahydrobiopterin in photoreception for UV-B-induced anthocyanin synthesis in carrot

Photochem Photobiol. 2014 Sep-Oct;90(5):1043-9. doi: 10.1111/php.12302. Epub 2014 Jul 16.

Abstract

Our previous studies of action spectra for UV-B-induced anthocyanin accumulation in cultured carrot cells indicated that a reduced form of pterin, possibly tetrahydrobiopterin, contributes to UV-B photoreception. In this report, we provide additional evidence for the involvement of pterin in UV-B light sensing. UV-B-induced phenylalanine ammonia-lyase (PAL) activity was considerably suppressed by N-acetylserotonin (an inhibitor of tetrahydrobiopterin biosynthesis), and this suppression was partially recovered by adding biopterin or tetrahydrobiobiopterin. In addition, protein(s) specifically bound to biopterin were detected by radiolabeling experiments in N-acetylserotonin-treated cells. Furthermore, diphenyleneiodonium, a potent inhibitor of electron transfer, completely suppressed UV-B-induced PAL activity. These results suggest the occurrence of an unidentified UV-B photoreceptor (other than UVR8, the tryptophan-based UV-B sensor originally identified in Arabidopsis) with reduced pterin in carrot cells. After reexamining published action spectra, we suggest that anthocyanin synthesis is coordinately regulated by these two UV-B sensors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anthocyanins / antagonists & inhibitors
  • Anthocyanins / biosynthesis*
  • Biopterins / analogs & derivatives*
  • Biopterins / antagonists & inhibitors
  • Biopterins / biosynthesis
  • Biopterins / metabolism
  • Biopterins / pharmacology
  • Daucus carota / drug effects
  • Daucus carota / metabolism
  • Daucus carota / radiation effects*
  • Electron Transport / drug effects
  • Electron Transport / radiation effects
  • Electrons*
  • Onium Compounds / pharmacology
  • Oxidation-Reduction
  • Phenylalanine Ammonia-Lyase / antagonists & inhibitors
  • Phenylalanine Ammonia-Lyase / metabolism
  • Photochemical Processes
  • Plant Proteins / antagonists & inhibitors
  • Plant Proteins / metabolism*
  • Serotonin / analogs & derivatives
  • Serotonin / pharmacology
  • Ultraviolet Rays

Substances

  • Anthocyanins
  • Onium Compounds
  • Plant Proteins
  • Biopterins
  • Serotonin
  • diphenyleneiodonium
  • Phenylalanine Ammonia-Lyase
  • sapropterin
  • N-acetylserotonin