title: Construction of signature-tagged mutant library in Mesorhizobium loti as a powerful tool for functional genomics.
abstract: Rhizobia are nitrogen-fixing soil bacteria that establish endosymbiosis with some leguminous plants. The completion of several rhizobial genome sequences provides opportunities for genome-wide functional studies of the physiological roles of many rhizobial genes. In order to carry out genome-wide phenotypic screenings, we have constructed a large mutant library of the nitrogen-fixing symbiotic bacterium, Mesorhizobium loti, by transposon mutagenesis. Transposon insertion mutants were generated using the signature-tagged mutagenesis (STM) technique and a total of 29,330 independent mutants were obtained. Along with the collection of transposon mutants, we have determined the transposon insertion sites for 7892 clones, and confirmed insertions in 3680 non-redundant M. loti genes (50.5% of the total number of M. loti genes). Transposon insertions were randomly distributed throughout the M. loti genome without any bias toward G+C contents of insertion target sites and transposon plasmids used for the mutagenesis. We also show the utility of STM mutants by examining the specificity of signature tags and test screenings for growth- and nodulation-deficient mutants. This defined mutant library allows for genome-wide forward- and reverse-genetic functional studies of M. loti and will serve as an invaluable resource for researchers to further our understanding of rhizobial biology.
authors.affiliation: Kazusa DNA Research Institute, 2-6-7 Kazusa-kamatari, Kisarazu, Chiba 292-0818, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Shimoda
authors.forename: Hisayuki
authors.initials: H
authors.lastname: Mitsui
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kamimatsuse
authors.forename: Kiwamu
authors.initials: K
authors.lastname: Minamisawa
authors.forename: Eri
authors.initials: E
authors.lastname: Nishiyama
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ohtsubo
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nagata
authors.forename: Masataka
authors.initials: M
authors.lastname: Tsuda
authors.forename: Sayaka
authors.initials: S
authors.lastname: Shinpo
authors.forename: Akiko
authors.initials: A
authors.lastname: Watanabe
authors.forename: Mitsuyo
authors.initials: M
authors.lastname: Kohara
authors.forename: Manabu
authors.initials: M
authors.lastname: Yamada
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tabata
authors.forename: Shusei
authors.initials: S
authors.lastname: Sato
mesh_terms: D020561:Alphaproteobacteria / Q000235:genetics*; D004251:DNA Transposable Elements; D015723:Gene Library; D016680:Genome, Bacterial; D023281:Genomics; D016254:Mutagenesis, Insertional; D010957:Plasmids / Q000235:genetics; D012230:Rhizobiaceae / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements