University of Brasília (UnB), Postgraduate Program in Agronomy, Faculty of Agronomy and Veterinary Medicine, Brasília 70910-900, Brazil.
University of Brasília (UnB), Postgraduate Program in Agronomy, Faculty of Agronomy and Veterinary Medicine, Brasília 70910-900, Brazil.
Microbiol Res. 2023 Oct;275:127465. doi: 10.1016/j.micres.2023.127465. Epub 2023 Jul 29.
The identification of antifungal compounds produced by microorganisms is crucial in the context of sustainable agriculture. Bacteria of the genus Bacillus have a broad spectrum of action that can influence plant growth and control pests, vectors of public health relevance and phytopathogens. Lipopeptides are the main compounds related to the biological control of several pathogen species. Strains with biotechnological potential are identified by means of in vitro bioassays and molecular tests. In this study, strains from the Bacillus Bank of Brazilian Agricultural Research Corporation (EMBRAPA/DF/Brazil) were selected to control the fungal pathogens Sclerotinia sclerotiorum and Fusarium oxysporum by pairing assays. The detection of genes for biosynthesis of antifungal compounds from strains with high pathogen-inhibition capacity was correlated with peptide synthesis, such as bacillomycin D, fengycin d, bacilysin and surfactin. Their gene expression in contact with the pathogen was analyzed by Real-Time PCR. The volatile organic compounds produced by selected Bacillus strains were identified and quantified. In co-culture assays, the inhibition zone between Bacillus strains and Sclerotinia sclerotiorum was evaluated by scanning electron microscopy. Thirteen potentially anti-pathogenic strains were selected. Genes related to the synthesis of antifungal peptides were detected in 11 of them. In five strains, all tested genes were detected. Bacillomycin was the most frequently found lipopeptide gene. The fungus-bacteria interaction potentiated the production of volatiles. Several ketones and other volatile compounds with antifungal activity were identified. Relevant morphological changes in the fungus were observed when paired with bacteria. The study demonstrated the efficacy of the selected strains with regard to the biological control of phytopathogens and their biotechnological potential.
在可持续农业的背景下，鉴定微生物产生的抗真菌化合物是至关重要的。芽孢杆菌属的细菌具有广泛的作用，可以影响植物生长和控制害虫、公共卫生相关的媒介和植物病原体。脂肽是与几种病原菌生物防治相关的主要化合物。具有生物技术潜力的菌株通过体外生物测定和分子试验来鉴定。在这项研究中，从巴西农业研究公司（EMBRAPA/DF/Brazil）的芽孢杆菌库中选择了一些菌株，通过配对试验来控制真菌病原体核盘菌和尖孢镰刀菌。具有高病原体抑制能力的菌株中合成抗真菌化合物的基因的检测与肽合成相关，如杆菌霉素 D、丰原素 D、杆菌肽和表面活性剂。通过实时 PCR 分析它们与病原体接触时的基因表达。对选定的芽孢杆菌菌株产生的挥发性有机化合物进行了鉴定和定量。在共培养试验中，通过扫描电子显微镜评估了芽孢杆菌菌株和核盘菌之间的抑菌带。筛选出了 13 株具有潜在抗病原性的菌株。在其中 11 株菌中检测到与合成抗真菌肽相关的基因。在 5 株菌中，所有测试的基因都被检测到。杆菌霉素是最常见的脂肽基因。真菌-细菌相互作用促进了挥发性物质的产生。鉴定出几种具有抗真菌活性的酮类和其他挥发性化合物。当与细菌配对时，观察到真菌的相关形态变化。该研究证明了所选菌株在防治植物病原体方面的功效及其生物技术潜力。
