title: Nitric oxide production induced in roots of Lotus japonicus by lipopolysaccharide from Mesorhizobium loti.
abstract: Lipopolysaccharide (LPS) is a bacterial molecule that induces nitric oxide (NO) production and triggers defense systems in plant-pathogen interactions. NO production is induced in the roots of Lotus japonicus after inoculation of the roots with its microsymbiont Mesorhizobium loti. However, the rhizobial molecule that induces NO production has not yet been identified. We investigated NO production in the roots of L. japonicus by treatment with LPS of M. loti. LPS was prepared by phenol-hot water extraction and separated into several fractions: polysaccharide, lipooligosaccharide, oligosaccharide and lipid A. In the roots of L. japonicus, NO production was observed with an NO-specific fluorescent dye 4, 10 and 24 h after treatment with each fraction of LPS. NO production was detected 4 h after treatment with all fractions. NO production was also detectable 24 h after treatment, except after treatment with the polysaccharide and oligosaccharide fractions. Expression of a class 1 hemoglobin gene and application of an NO scavenger showed that the treatment with LPS and LOS induced a similar response to inoculation with M. loti. These data suggest that LPS of M. loti induces NO production after inoculation with M. loti.
authors.affiliation: Graduate School of Science and Engineering, Kagoshima University, Kagoshima 890-0065, Japan.
authors.forename: Ei-ichi
authors.initials: E
authors.lastname: Murakami
authors.forename: Maki
authors.initials: M
authors.lastname: Nagata
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Shimoda
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Kucho
authors.forename: Shiro
authors.initials: S
authors.lastname: Higashi
authors.forename: Mikiko
authors.initials: M
authors.lastname: Abe
authors.forename: Masahito
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Toshiki
authors.initials: T
authors.lastname: Uchiumi
mesh_terms: D001565:Benzoates / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D006454:Hemoglobins / Q000235:genetics / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000302:isolation & purification / Q000378:metabolism*; D000070116:Lotus / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D059128:Mesorhizobium / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013559:Symbiosis; D013997:Time Factors
chemical_list: D001565:Benzoates; D016166:Free Radical Scavengers; D006454:Hemoglobins; D007093:Imidazoles; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides; C079393:1,3-dihydroxy-4,4,5,5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole; D009569:Nitric Oxide