Plant growth promotion abilities and microscale bacterial dynamics in the rhizosphere of Lupin analysed by phytate utilization ability.
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.
Unno
Yusuke
Y
Graduate School of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo 060-8589, Japan.
Okubo
Kenzo
K
Wasaki
Jun
J
Shinano
Takuro
T
Osaki
Mitsuru
M
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
D004269:DNA, Bacterial; D007295:Inositol Phosphates; D012336:RNA, Ribosomal, 16S; D010758:Phosphorus; D002244:Carbon; D010833:Phytic Acid