Blue light regulates the accumulation of two psbD-psbC transcripts in barley chloroplasts.
Synthesis of D2, a Photosystem II reaction center protein encoded by psbD, is differentially maintained during light-induced chloroplast maturation. The continued synthesis of D2 is paralleled by selective light-induced accumulation of two psbD-psbC transcripts which share a common 5' terminus. In the present study, we examine the nature of the photoreceptor and the fluence requirement for psbD-psbC transcript induction. The light-induced change in psbD-psbC RNA population can be detected between 1 and 2 h after 4.5 day old dark-grown barley seedlings are transferred to the light. Light-induced transcript accumulation occurs normally in the chlorophyll-deficient barley mutant, xan-f10, indicating that light-activated chlorophyll formation and photosynthesis are not required for RNA induction. High fluence blue light fully induces psbD-psbC transcript accumulation; low or high fluence red or far-red light do not. However, psbD-psbC transcript accumulation elicited by blue light pulses can be partially attenuated if far-red light is given immediately following the blue light treatment. Thus, although blue light is needed to initiate transcript accumulation, phytochrome modulates the amplitude of the response. Pretreatment of dark-grown plants with cycloheximide blocks light-induced psbD-psbC transcript accumulation. This could implicate a blue-light responsive nuclear gene in the light-induced accumulation of the two psbD-psbC transcripts.
Gamble
P E
PE
Department of Biochemistry and Biophysics, Texas A&M University, College Station 77843-2128.
Mullet
J E
JE
D000612:4-Aminobutyrate Transaminase / Q000037:antagonists & inhibitors; D000596:Amino Acids / Q000494:pharmacology; D002701:Chloramphenicol / Q000494:pharmacology; D002734:Chlorophyll / Q000235:genetics*; D002736:Chloroplasts / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D002523:Edible Grain / Q000235:genetics*; D005786:Gene Expression Regulation; D005796:Genes; D001467:Hordeum / Q000235:genetics*; D008027:Light; D045342:Light-Harvesting Protein Complexes; D009154:Mutation; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010834:Phytochrome / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics*; D014176:Protein Biosynthesis; D012313:RNA / Q000032:analysis; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects
D000596:Amino Acids; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D010834:Phytochrome; D002734:Chlorophyll; D012313:RNA; D002701:Chloramphenicol; C050326:4-amino-5-fluoropent-2-enoic acid; D003513:Cycloheximide; D000612:4-Aminobutyrate Transaminase