title: Plant growth promotion abilities and microscale bacterial dynamics in the rhizosphere of Lupin analysed by phytate utilization ability.
abstract: In the rhizosphere, phosphorus (P) levels are low because of P uptake into the roots. Rhizobacteria live on carbon (C) exuded from roots, and may contribute to plant nutrition by liberating P from organic compounds such as phytates. We isolated over 300 phytate (Na-inositol hexa-phosphate; Na-IHP)-utilizing bacterial strains from the rhizosheath and the rhizoplane of Lupinus albus (L.). Almost all of the isolates were classified as Burkholderia based on 16S rDNA sequence analysis. Rhizosheath isolates cultured with Na-IHP as the only source of C and P showed lower P uptake at the same extracellular phytase activity than rhizoplane strains, suggesting that bacteria from the rhizosheath utilized phytate as a C source. Many isolates also utilized insoluble phytate (Al-IHP and/or Fe-IHP). In co-culture with Lotus japonicus seedlings, some isolates promoted plant growth significantly.
authors.affiliation: Graduate School of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo 060-8589, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Unno
authors.forename: Kenzo
authors.initials: K
authors.lastname: Okubo
authors.forename: Jun
authors.initials: J
authors.lastname: Wasaki
authors.forename: Takuro
authors.initials: T
authors.lastname: Shinano
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Osaki
mesh_terms: D019117:Burkholderia / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D007295:Inositol Phosphates / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D010833:Phytic Acid / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000382:microbiology* / Q000502:physiology; D012336:RNA, Ribosomal, 16S / Q000032:analysis / Q000235:genetics; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D007295:Inositol Phosphates; D012336:RNA, Ribosomal, 16S; D010758:Phosphorus; D002244:Carbon; D010833:Phytic Acid