Modulation of gene expression of carotene biosynthesis-related protein by photosynthetic electron transport for the acclimation of intertidal macroalga Ulva fasciata to hypersalinity and excess light

• Published in: Physiologia plantarum Vol. 144; no. 3; pp. 225 - 237
• Main Authors: Hsu, Yuan-Ting, Lee, Tse-Min
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.03.2012; Blackwell
• Subjects: Acclimation; Acclimatization; Biological and medical sciences; Carotenoids - biosynthesis; Carotenoids - genetics; CBR protein; Cytochrome b6f Complex - genetics; Cytochrome b6f Complex - metabolism; Cytochromes; Dibromothymoquinone - pharmacology; Diuron - pharmacology; Electron transfer; Electron Transport; Energy; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant; Genes, Plant; Hydrogen peroxide; Hydrogen Peroxide - metabolism; Hydrogen Peroxide - pharmacology; iron-sulfur proteins; Light; Light effects; Oxidative stress; Oxygen; Oxygen - metabolism; Photochemical Processes; Photosynthesis; Photosystem II Protein Complex - genetics; Photosystem II Protein Complex - metabolism; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - metabolism; Polyenes - pharmacology; quinol oxidase; Reactive Oxygen Species - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Plant - genetics; RNA, Plant - metabolism; Salinity; Salinity effects; Sodium Chloride - pharmacology; Thiourea - analogs & derivatives; Thiourea - pharmacology; Ulva - genetics; Ulva - metabolism; Ulva - radiation effects; Ulva fasciata; Carotene; Algae; Electron transfer; Marine alga; Biosynthesis; Ulva; Gene expression; Protein; Chlorophyta; Plant physiology; Ulvophyceae; Light; Modulation; Photosynthesis; Adaptation
• ISSN: 0031-9317; 1399-3054
• DOI: 10.1111/j.1399-3054.2011.01547.x

A gene (UfCBR) encoding carotene biosynthesis‐related (CBR) protein that potentially functions for the dissipation of excessive energy has been cloned from the intertidal green macroalga Ulva fasciata Delile. Hypersalinity and high light ≥300 µmol m−2 s−1 increased both UfCBR mRNA level and non‐photochemical quenching (NPQ). The increase of UfCBR mRNA level and NPQ by high light was inhibited by treatment of photosynthetic electron transport inhibitor, 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea or 2,5‐dibromo‐3‐methyl‐6‐isopropyl‐p‐benzoquinone, but not by stigmatellin, an inhibitor that blocks electron transfer from quinol oxidase to iron–sulfur protein in cytochrome b6f complex. Treatment of dimethylthiourea, an H2O2 scavenger, under 1200 µmol m−2 s−1 condition inhibited H2O2 accumulation but did not affect UfCBR mRNA level, while treatment of H2O2 in 150 µmol m−2 s−1 condition decreased UfCBR mRNA level. Thus, an reactive oxygen species‐independent redox control via a more reduced state downstream the cytochrome b6f complex is involved in high light up‐regulation of UfCBR expression in U. fasciata. The expression of UfCBR in U. fasciata against oxidative stress occurring in high light or high salinity in relation to NPQ is discussed.