title: Effects of Light-Emitting Diode Irradiation on Growth Characteristics and Regulation of Porphyrin Biosynthesis in Rice Seedlings.
abstract: We examined the effects of light quality on growth characteristics and porphyrin biosynthesis of rice seedlings grown under different wavelengths from light emitting diodes (LEDs). After 10 days of exposure to various wavelengths of LEDs, leaf area and shoot biomass were greater in seedlings grown under white and blue LEDs than those of green and red LEDs. Both green and red LED treatments drastically decreased levels of protoporphyrin IX (Proto IX) and Mg-porphyrins compared to those of white LED, while levels of Mg-Proto IX monomethyl ester and protochlorophyllide under blue LED were decreased by 21% and 49%, respectively. Transcript levels ofPPO1were greatly upregulated in seedlings grown under red LED compared to white LED, whereas transcript levels ofHO2andCHLDwere upregulated under blue LED. Overall, most porphyrin biosynthetic genes in the Fe-porphyrin branch remained almost constant or upregulated, while most genes in the Mg-porphyrin branch were downregulated. Expression levels of nuclear-encoded photosynthetic genesLhcbandRbcSnoticeably decreased after exposure to blue and red LEDs, compared to white LED. Our study suggests that specific wavelengths of LED greatly influence characteristics of growth in plants partly through altering the metabolic regulation of the porphyrin biosynthetic pathway, and possibly contribute to affect retrograde signaling.
authors.affiliation: School of Life Sciences and Biotechnology, BK21 Plus KNU Creative Bioresearch Group, Kyungpook National University, Daegu 41566, Korea. thlien91@yahoo.com.
authors.forename: Lien Hong
authors.initials: LH
authors.lastname: Tran
authors.affiliation: School of Life Sciences and Biotechnology, BK21 Plus KNU Creative Bioresearch Group, Kyungpook National University, Daegu 41566, Korea. sjung@knu.ac.kr.
authors.forename: Sunyo
authors.initials: S
authors.lastname: Jung
mesh_terms: D018506:Gene Expression Regulation, Plant; D008027:Light; D012275:Oryza / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011166:Porphyrins / Q000096:biosynthesis*; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects
chemical_list: D010940:Plant Proteins; D011166:Porphyrins
keywords: LED (light emitting diode); growth; nuclear-encoded photosynthetic gene; photosynthetic pigment; porphyrin biosynthesis