Data/hora: 12/06/2024 07:28:24

Provedor de dados: | 19
País: | Japan

Título:

Biological control of Verticillium black spot of Japanese radish using Bacillus spp. and genotypic differentiation of selected antifungal Bacillus strains with antibiotic marker

Bacillus属菌によるダイコン黒点病の生物防除と抗生物質耐性マーカーを付与した分離菌の遺伝的特徴

Autores: | Kawai, Ayako; Kusunoki, Kaori; Aiuchi, Daigo; Koike, Masanori; Tani, Masayuki; Kuramochi, Katsuhisa; 川井, 彩子; 楠木, 芳; 相内, 大吾; 小池, 正徳; 谷, 昌幸; 倉持, 勝久.
Data: | 2006-10
Ano: | 2006
Palavras-chave: | Bacillus spp.; Biological control; Verticillium black spot of Japanese radish; Verticillium dahliae.
Resumo: | Bacillus species can form endospores and have broad-spectrum activity of their antibiotics. For that reason, they offer several advantages over other bacteria for protection against root pathogens. This work was intended to determine the ability of Bacillus spp. to inhibit Verticillium dahliae. First, antagonistic activities of Bacillus spp. were studied in greenhouse trials. These results suggest that the bacterium can control soil-borne diseases. Secondly, to investigate the situation in a culture environment, Bacillus spp. were examined for their activity to control Verticillium black spot of Japanese radish and plant-growth promotion rhizobacteria (PGPR) effects in a field. After 2 months, these bacteria reduced Verticillium black spot of Japanese radish. The disease severity of those Biological Control Agent (BCA) treatments was less than in the pathogen control treatment. Furthermore, the plants treated with KB-3 showed the best PGPR effect. Field conditions show that Bacillus spp. isolate KB-2, KB-3 is a potential BCA against V. dahliae. Subsequently, to select bacteria that are able to more control disease and more colonize in the plants and which facilitate recovery from soil and plants, Bacillus spp. were isolated from roots and were made resistant to ampicillin using UV irradiation. In all, 17 ampicillin-resistant mutants were tested for inhibition V. dahliae and F. oxysporum in vitro. Five bacteria isolates displayed inhibitory effects on FOM. All bacteria isolates indicated high antibiotic activity on V. dahliae. Then, to investigate the molecular characterization of all isolated strains of Bacillus spp., PCR amplification of the 16S-23S rDNA intergenic transcribed spacer (ITS-PCR), restriction fragment length polymorphism of the ITS-PCR (ITS-PCR RFLP), and enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) were conducted. The ITS-PCR and ITS-PCR RFLP results suggest that KB-1 and strains of isolated from KB-1 were identical. Furthermore, those of the strains of KB-2 were also identical. However, KB-3 and all strains of isolates from KB-3 were different by ITS-PCR RFLP. Results suggest that the strains of isolates from KB-3 resembled those of KB-2. Using ERIC-PCR, 20 strains of Bacillus spp. could be distinguished. Bacillus属菌は芽胞を形成することで悪条件下でも生存することができ、また広い宿主範囲をもつ抗生物質を産生する。このことから生物防除資材として適しているとされており、その可能性を探って多様な研究が行われている。そこで本実験では、キヨモト・バイオ（株）より分譲されたBacillus属菌3菌株（KB-1, KB-2, KB-3）を用いてダイコン黒点病に対する生物防除資材としての可能性について検討した。二回のポット試験を行った後、圃場内で発病抑制効果をみた。その結果、すべての菌接種区において病原菌単独処理区と比較して病気を抑制している傾向がみられ、特にKB-2、KB-3接種区で優れた効果がみられた。さらに土壌や植物体内から菌を分離しやすくし、より正確なデータを得るために、Bacillus属菌3菌株にマーカーを付与した。すなわち、UV照射により突然変異を生じさせ、アンピシリンに対する抵抗性をもつBacillus系統を選抜した。以上の処理によって得られた合計17菌株を用いて対峙培養を行い、Verticillium dahliaeおよびFusarium oxysporumに対する拮抗作用を調査した。その結果、F. oxysporumに対しては6菌株で、V. dahliaeに対してはすべての菌株で優れた抑制効果がみられた。このことから変異株は病原菌の生育を抑制することが示唆された。また、ITS-PCR, ITS-PCR-RFLP, ERIC-PCRを用いてKB-1, KB-2, KB-3とアンピシリン耐性変異株の遺伝的特徴を調べた。これにより遺伝的にもこれらの菌を識別することが可能となり、今後のポット試験・圃場試験での有効的な活用が期待される。
Idioma: | Inglês

Identificador:

帯大研報

http://ir.obihiro.ac.jp/dspace/handle/10322/97

Editor: | 帯広畜産大学
Formato: | application/pdf
Fonte: | 帯広畜産大学