title: Molecular characterization of the Lotus japonicus NRT1(PTR) and NRT2 families.
abstract: Nitrate is an essential element for plant growth, both as a primary nutrient in the nitrogen assimilation pathway and as an important signal for plant development. Low- and high-affinity transport systems are involved in the nitrate uptake from the soil and its distribution between different plant tissues. By an in silico search, we identified putative members of both systems in the model legume Lotus japonicus. We investigated, by a time course analysis, the transcripts abundance in root tissues of nine and four genes encoding putative low-affinity (NRT1) and high-affinity (NRT2) nitrate transporters, respectively. The genes were sub-classified as inducible, repressible and constitutive on the basis of their responses to provision of nitrate, auxin or cytokinin. Furthermore, the analysis of the pattern of expression in root and nodule tissues after Mesorhizobium loti inoculation permitted the identification of sequences significantly regulated during the symbiotic interaction. The interpretation of the global regulative networks obtained allowed to postulate roles for nitrate transporters as possible actors in the cross-talks between different signalling pathways triggered by biotic and abiotic factors.
authors.affiliation: Institute of Genetics and Biophysics A. Buzzati Traverso, Via P. Castellino 111, 80131, Napoli, Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Criscuolo
authors.forename: Vladimir Totev
authors.initials: VT
authors.lastname: Valkov
authors.forename: Aurora
authors.initials: A
authors.lastname: Parlati
authors.forename: Ludovico Martin
authors.initials: LM
authors.lastname: Alves
authors.forename: Maurizio
authors.initials: M
authors.lastname: Chiurazzi
mesh_terms: D027321:Anion Transport Proteins / Q000235:genetics* / Q000378:metabolism; D003583:Cytokinins / Q000494:pharmacology; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D053263:Gene Regulatory Networks / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D007210:Indoleacetic Acids / Q000494:pharmacology; D000070116:Lotus / Q000187:drug effects / Q000235:genetics* / Q000382:microbiology; D059128:Mesorhizobium / Q000187:drug effects / Q000502:physiology; D005810:Multigene Family / Q000235:genetics*; D000091285:Nitrate Transporters; D009566:Nitrates / Q000494:pharmacology; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D053204:Root Nodules, Plant / Q000166:cytology / Q000187:drug effects / Q000382:microbiology; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D027321:Anion Transport Proteins; D003583:Cytokinins; D007210:Indoleacetic Acids; D000091285:Nitrate Transporters; D009566:Nitrates; D010940:Plant Proteins; D012333:RNA, Messenger