title: Orange protein has a role in phytoene synthase stabilization in sweetpotato.
abstract: Carotenoids have essential roles in light-harvesting processes and protecting the photosynthetic machinery from photo-oxidative damage. Phytoene synthase (PSY) and Orange (Or) are key plant proteins for carotenoid biosynthesis and accumulation. We previously isolated the sweetpotato (Ipomoea batatas) Or gene (IbOr), which is involved in carotenoid accumulation and salt stress tolerance. The molecular mechanism underlying IbOr regulation of carotenoid accumulation was unknown. Here, we show that IbOr has an essential role in regulating IbPSY stability via its holdase chaperone activity both in vitro and in vivo. This protection results in carotenoid accumulation and abiotic stress tolerance. IbOr transcript levels increase in sweetpotato stem, root, and calli after exposure to heat stress. IbOr is localized in the nucleus and chloroplasts, but interacts with IbPSY only in chloroplasts. After exposure to heat stress, IbOr predominantly localizes in chloroplasts. IbOr overexpression in transgenic sweetpotato and Arabidopsis conferred enhanced tolerance to heat and oxidative stress. These results indicate that IbOr holdase chaperone activity protects IbPSY stability, which leads to carotenoid accumulation, and confers enhanced heat and oxidative stress tolerance in plants. This study provides evidence that IbOr functions as a molecular chaperone, and suggests a novel mechanism regulating carotenoid accumulation and stress tolerance in plants.
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Daejeon 34141, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), 217 Gajeong-ro, Daejeon 34113, Korea.
authors.forename: Seyeon
authors.initials: S
authors.lastname: Park
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Daejeon 34141, Korea.
authors.forename: Ho Soo
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Division of Applied Life Science (BK21 Plus program), Gyeongsang National University, 501 Jinjudae-ro, Jinju 52828, Korea.|National Institute of Ecology, 1210 Geumgang-ro, Maseo-myeon, Seocheon-gun 33657, Korea.
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Jung
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Daejeon 34141, Korea.
authors.forename: Sun Ha
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Daejeon 34141, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), 217 Gajeong-ro, Daejeon 34113, Korea.
authors.forename: Chang Yoon
authors.initials: CY
authors.lastname: Ji
authors.affiliation: Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources, Northwest A &F University, Shaanxi 712100, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Daejeon 34141, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), 217 Gajeong-ro, Daejeon 34113, Korea.
authors.forename: Jae Cheol
authors.initials: JC
authors.lastname: Jeong
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Daejeon 34141, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), 217 Gajeong-ro, Daejeon 34113, Korea.
authors.forename: Haeng-Soon
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Division of Applied Life Science (BK21 Plus program), Gyeongsang National University, 501 Jinjudae-ro, Jinju 52828, Korea.
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Daejeon 34141, Korea.|Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), 217 Gajeong-ro, Daejeon 34113, Korea.
authors.forename: Sang-Soo
authors.initials: SS
authors.lastname: Kwak
mesh_terms: D000222:Adaptation, Physiological; D004795:Enzyme Stability; D018506:Gene Expression Regulation, Plant; D018869:Heat-Shock Response; D027723:Ipomoea batatas / Q000201:enzymology* / Q000235:genetics; D008954:Models, Biological; D018832:Molecular Chaperones / Q000378:metabolism; D008970:Molecular Weight; D064251:Multifunctional Enzymes / Q000378:metabolism*; D018384:Oxidative Stress; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011485:Protein Binding; D055503:Protein Multimerization; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013312:Stress, Physiological
chemical_list: D018832:Molecular Chaperones; D064251:Multifunctional Enzymes; D010940:Plant Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins