title: A Sweetpotato Geranylgeranyl Pyrophosphate Synthase Gene, IbGGPS, Increases Carotenoid Content and Enhances Osmotic Stress Tolerance in Arabidopsis thaliana.
abstract: Sweetpotato highly produces carotenoids in storage roots. In this study, a cDNA encoding geranylgeranyl phyrophosphate synthase (GGPS), named IbGGPS, was isolated from sweetpotato storage roots. Green fluorescent protein (GFP) was fused to the C-terminus of IbGGPS to obtain an IbGGPS-GFP fusion protein that was transiently expressed in both epidermal cells of onion and leaves of tobacco. Confocal microscopic analysis determined that the IbGGPS-GFP protein was localized to specific areas of the plasma membrane of onion and chloroplasts in tobacco leaves. The coding region of IbGGPS was cloned into a binary vector under the control of 35S promoter and then transformed into Arabidopsis thaliana to obtain transgenic plants. High performance liquid chromatography (HPLC) analysis showed a significant increase of total carotenoids in transgenic plants. The seeds of transgenic and wild-type plants were germinated on an agar medium supplemented with polyethylene glycol (PEG). Transgenic seedlings grew significantly longer roots than wild-type ones did. Further enzymatic analysis showed an increased activity of superoxide dismutase (SOD) in transgenic seedlings. In addition, the level of malondialdehyde (MDA) was reduced in transgenics. qRT-PCR analysis showed altered expressions of several genes involved in the carotenoid biosynthesis in transgenic plants. These data results indicate that IbGGPS is involved in the biosynthesis of carotenoids in sweetpotato storage roots and likely associated with tolerance to osmotic stress.
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China.
authors.forename: Shaozhen
authors.initials: S
authors.lastname: He
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China.
authors.forename: Degao
authors.initials: D
authors.lastname: Liu
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri, United States of America.
authors.forename: Gunvant B
authors.initials: GB
authors.lastname: Patil
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhai
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China.
authors.forename: Feibing
authors.initials: F
authors.lastname: Wang
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri, United States of America.
authors.forename: Troy J
authors.initials: TJ
authors.lastname: Stephenson
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China.
authors.forename: Yannan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri, United States of America.
authors.forename: Babu
authors.initials: B
authors.lastname: Valliyodan
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri, United States of America.
authors.forename: Henry T
authors.initials: HT
authors.lastname: Nguyen
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis and Utilization, Ministry of Education, China Agricultural University, Beijing, China.
authors.forename: Qingchang
authors.initials: Q
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000502:physiology*; D002338:Carotenoids / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018506:Gene Expression Regulation, Plant; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase / Q000235:genetics / Q000378:metabolism*; D027723:Ipomoea batatas / Q000201:enzymology*; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D018517:Plant Roots / Q000502:physiology; D030821:Plants, Genetically Modified / Q000502:physiology*; D055049:Salt Tolerance; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological
chemical_list: D018076:DNA, Complementary; D002338:Carotenoids; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase