title: Bending of protonema cells in a plastid glycolate/glycerate transporter knockout line of Physcomitrella patens.
abstract: Arabidopsis LrgB (synonym PLGG1) is a plastid glycolate/glycerate transporter associated with recycling of 2-phosphoglycolate generated via the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). We isolated two homologous genes (PpLrgB1 and B2) from the moss Physcomitrella patens. Phylogenetic tree analysis showed that PpLrgB1 was monophyletic with LrgB proteins of land plants, whereas PpLrgB2 was divergent from the green plant lineage. Experiments with PpLrgB-GFP fusion proteins suggested that both PpLrgB1 and B2 proteins were located in chloroplasts. We generated PpLrgB single (∆B1 and ∆B2) and double (∆B1/∆B2)-knockout lines using gene targeting of P. patens. The ∆B1 plants showed decreases in growth and photosynthetic activity, and their protonema cells were bent and accumulated glycolate. However, because ∆B2 and ∆B1/∆B2 plants showed no obvious phenotypic change relative to the wild-type or ∆B1 plants, respectively, the function of PpLrgB2 remains unclear. Arabidopsis LrgB could complement the ∆B1 phenotype, suggesting that the function of PpLrgB1 is the same as that of AtLrgB. When ∆B1 was grown under high-CO2 conditions, all novel phenotypes were suppressed. Moreover, protonema cells of wild-type plants exhibited a bending phenotype when cultured on media containing glycolate or glycerate, suggesting that accumulation of photorespiratory metabolites caused P. patens cells to bend.
authors: Graduate School of Science and Technology, Kumamoto University, Kurokami, Kumamoto 860-8555, Japan.
authors: Jin
authors: J
authors: Nakahara
authors: Graduate School of Science and Technology, Kumamoto University, Kurokami, Kumamoto 860-8555, Japan.
authors: Katsuaki
authors: K
authors: Takechi
authors: Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science (CSRS), Yokohama, Kanagawa 230-0045, Japan.
authors: Fumiyoshi
authors: F
authors: Myouga
authors: Graduate School of Science and Technology, Kumamoto University, Kurokami, Kumamoto 860-8555, Japan.
authors: Yasuko
authors: Y
authors: Moriyama
authors: Faculty of Science, Kumamoto University, Kurokami, Kumamoto 860-8555, Japan.
authors: Hiroshi
authors: H
authors: Sato
authors: Graduate School of Science and Technology, Kumamoto University, Kurokami, Kumamoto 860-8555, Japan; Center for Marine Environment Studies, Kumamoto University, Kurokami, Kumamoto 860-8555, Japan.
authors: Susumu
authors: S
authors: Takio
authors: Graduate School of Science and Technology, Kumamoto University, Kurokami, Kumamoto 860-8555, Japan; Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555, Japan.
authors: Hiroyoshi
authors: H
authors: Takano
mesh_terms: D029681:Arabidopsis Proteins / Q000378:metabolism; D001696:Biomechanical Phenomena / Q000187:drug effects; D019068:Bryopsida / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D055786:Gene Knockout Techniques; D017343:Genes, Plant; D005816:Genetic Complementation Test; D005988:Glyceric Acids / Q000494:pharmacology; D006016:Glycolates / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D010641:Phenotype; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D018087:Plastids / Q000378:metabolism* / Q000648:ultrastructure; D012689:Sequence Homology, Nucleic Acid; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014170:Transformation, Genetic / Q000187:drug effects
chemical_list: D029681:Arabidopsis Proteins; D005988:Glyceric Acids; D006016:Glycolates; C571061:LrgB protein, Arabidopsis; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010940:Plant Proteins; C031149:glycolic acid; D049452:Green Fluorescent Proteins; C042971:glyceric acid