Bacillus and Streptomyces were selected as broad-spectrum antagonists against soilborne pathogens from arid areas in Egypt
Bacillus and Streptomyces were selected as broad-spectrum antagonists against soilborne pathogens from arid areas in Egypt
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DOI：
10.1111/1574-6968.12089
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发表时间：
2013-05-01
影响因子：
2.1
通讯作者：
Berg, Gabriele
中科院分区：
文献类型：
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作者：
Koeberl, Martina;Ramadan, Elshahat M.;Berg, Gabriele
在沙漠农业中通过抑病细菌进行植物保护需要适应独特干旱条件的特定生物控制剂（BCA）。我们进行了生态学研究的地下社区在沙漠农场土壤和未经处理的沙漠土壤，并根据这些发现，选择拮抗剂进行了分级评价。与土壤和栽培药用植物中细菌群落的高度特异性的16 S rRNA指纹图谱相反，真菌群落的内部转录间隔区图谱的歧视性较小，主要特征是潜在的病原体。因此，我们集中在体外细菌拮抗剂对病原真菌。基于抗真菌潜力和基因组多样性，选择了45种独特的菌株并进行了详细的表征。芽孢杆菌/类芽孢杆菌最常见的农业土壤中，但拮抗剂从周围的沙漠土壤主要属于链霉菌。所有菌株产生的抗生素对线虫南方根结线虫，和三分之一的细菌病原体青枯雷尔氏菌表现出额外的活性。共筛选出13种具有抗菌、抗真菌和杀线虫活性的广谱拮抗菌，分别属于芽孢杆菌属和链霉菌属的7种不同的细菌。这些革兰氏阳性的孢子形成细菌是有希望的抗旱BCAs和抗生素的潜在来源。荧光原位杂交结合激光扫描显微镜观察了它们的根际竞争力。
Plant protection via disease-suppressive bacteria in desert farming requires specific biological control agents (BCAs) adapted to the unique arid conditions. We performed an ecological study of below-ground communities in desert farm soil and untreated desert soil, and based on these findings, selected antagonists were hierarchically evaluated. In contrast to the highly specific 16S rRNA fingerprints of bacterial communities in soil and cultivated medicinal plants, internal transcribed spacer profiles of fungal communities were less discriminative and mainly characterised by potential pathogens. Therefore, we focused on in vitro bacterial antagonists against pathogenic fungi. Based on the antifungal potential and genomic diversity, 45 unique strains were selected and characterised in detail. Bacillus/Paenibacillus were most frequently identified from agricultural soil, but antagonists from the surrounding desert soil mainly belonged to Streptomyces. All strains produced antibiotics against the nematode Meloidogyne incognita, and one-third showed additional activity against the bacterial pathogen Ralstonia solanacearum. Altogether, 13 broad-spectrum antagonists with antibacterial, antifungal and nematicidal activity were found. They belong to seven different bacterial species of the genera Bacillus and Streptomyces. These Gram-positive, spore-forming bacteria are promising drought-resistant BCAs and a potential source for antibiotics. Their rhizosphere competence was shown by fluorescence in situ hybridisation combined with laser scanning microscopy.