2023 Fiscal Year Final Research Report
Characterization of tolerance to high aluminum concentrations in plant growth-promoting bacteria adapted to actual acid sulfate soils.
| Project/Area Number |
21K12298
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 64020:Environmental load reduction and remediation-related
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| Research Institution | Nihon University |
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Principal Investigator |
AIZAWA Tomoko 日本大学, 生物資源科学部, 講師 (60398849)
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| Co-Investigator(Kenkyū-buntansha) |
浦井 誠 東京農業大学, 生命科学部, 教授 (20398853)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 酸性土壌 / アルミニウム / 植物根圏微生物 / バイオフィルム |
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| Outline of Final Research Achievements |
A novel aluminum-tolerant bacterial strain CA42 was isolated from the aquatic plant Eleocharis dulcis, which grows in a highly acidic swamp in Vietnam. Inoculation with CA42 allowed Oryza sativa to grow in the presence of 300 μM AlCl3 at pH 3.5, and biofilms were observed around the roots. Using 16S rRNA gene sequencing analysis, the strain was identified as Pullulanibacillus sp. CA42. This strain secreted large amounts of an extracellular polysaccharide (CA42 EPS). Furthermore, the aluminum tolerance of CA42 cells was attenuated by pullulanase treatment directly on the live CA42 cells. These results suggest that CA42 EPS adsorbs aluminum ions and is involved in the aluminum tolerance mechanism of Pullulanibacillus sp. CA42. Thus, this strain may be a potential plant growth-promoting bacterium in acidic soils. In addition, this study is the first to report a glycogen-like polysaccharide that adsorbs aluminum ions.
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| Free Research Field |
微生物生態学
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| Academic Significance and Societal Importance of the Research Achievements |
酸性硫酸塩土壌とは、海成粘土層が開墾などにより地表に露出し、これが酸化して生じる硫酸が原因となって土壌および周辺水域がpH1～4という強酸性を呈する土壌である。東南アジアの酸性硫酸塩土壌の湿地に適応する植物を探索し、その根圏からイネの生育促進能をもつ有用微生物群を得てきた。その中で、酸性条件下で植物生育促進能があり、かつ細菌の中で最も高濃度のアルミニウム耐性を示すAL46株やイネの根圏でバイオフィルムを形成するCA42株を得た。本研究は、AL46株のプロテオーム解析およびCA42株のバイオフィルムの構造解析により、新たなアルミニウム耐性・酸性土壌適応機構の一端を明らかにすることができた。
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