title: Impact of the plastidial stringent response in plant growth and stress responses.
abstract: The regulatory nucleotide guanosine 5'-diphosphate 3'-diphosphate (ppGpp), which was originally identified in Escherichia coli, controls the expression of a large gene set and many enzyme activities. The ppGpp-dependent control of cell activities is referred to as the stringent response. Recently, genes responsible for the synthesis and degradation of ppGpp have been identified not only in bacteria, but also in eukaryotes, including plants and animals, indicating that the stringent response is, unexpectedly, widely conserved. However, the exact function of the eukaryotic stringent response remains elusive. Here, we isolated an Arabidopsis mutant that overproduces ppGpp in chloroplasts. This mutant shows metabolite reduction, dwarf chloroplasts and significantly suppressed plastidial transcription and translation. Under nutrient-deficient conditions, the mutant shows more robust growth than the wild type. These results indicate that the ppGpp-dependent control of the organelle function is crucial for the systematic growth of host organisms.
authors.affiliation: Graduate School of Bioscience &Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors.forename: Mikika
authors.initials: M
authors.lastname: Maekawa
authors.affiliation: Graduate School of Bioscience &Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors.forename: Rina
authors.initials: R
authors.lastname: Honoki
authors.affiliation: Graduate School of Bioscience &Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Ihara
authors.affiliation: Graduate School of Bioscience &Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Sato
authors.affiliation: Faculty of Agriculture, Yamagata University, Tsuruoka 997-8555, Japan.|RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Oikawa
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Kanno
authors.affiliation: Graduate School of Bioscience &Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.|Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8551, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohta
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Seo
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan.|Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Saito
authors.affiliation: Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8551, Japan.|Center for Biological Resources &Informatics, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Masuda