title: Overexpression of RelA/SpoT homologs, PpRSH2a and PpRSH2b, induces the growth suppression of the moss Physcomitrella patens.
abstract: Two genes encoding RelA/SpoT homologs, PpRSH2a and PpRSH2b, which are involved in the synthesis of bacterial alarmone guanosine 5'-diphosphate 3'-diphosphate (ppGpp) for the stringent response, were isolated from the moss, Physcomitrella patens. A complementary analysis of PpRSH2a and PpRSH2b in Escherichia coli showed that these genes had ppGpp biosynthetic activity. The recombinant PpRSH2a and PpRSH2b were also shown to synthesize ppGpp in vitro. Both proteins were localized to the chloroplasts of P. patens. Expression of the PpRSH genes was induced upon treatment with abscisic acid or abiotic stresses, such as dehydration and UV irradiation. Overexpression of PpRSH2a and PpRSH2b caused suppression of the growth in response to 1% (w/v) of glucose. The present study suggests the existence of a mechanism to regulate the growth of P. patens, which is governed by plant RSH in chloroplasts.
authors.affiliation: a Research Faculty of Agriculture, Division of Applied Bioscience , Hokkaido University , Sapporo , Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Sato
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Takahashi
authors.forename: Kozo
authors.initials: K
authors.lastname: Ochi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Matsuura
authors.forename: Kensuke
authors.initials: K
authors.lastname: Nabeta
authors.forename: Kosaku
authors.initials: K
authors.lastname: Takahashi
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D019068:Bryopsida / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000528:radiation effects; D002736:Chloroplasts / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects; D003890:Desiccation; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005947:Glucose / Q000378:metabolism; D006159:Guanosine Tetraphosphate / Q000096:biosynthesis*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008025:Ligases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological; D014466:Ultraviolet Rays
chemical_list: D007527:Isoenzymes; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011994:Recombinant Proteins; D006159:Guanosine Tetraphosphate; D000040:Abscisic Acid; D008025:Ligases; C028812:guanosine 3',5'-polyphosphate synthetases; D005947:Glucose
keywords: abscisic acid; chloroplast; environmental stress; ppGpp; stringent response