White mold disease, caused by Sclerotinia sclerotiorum the devastating pathogen, attacks green beans (Phaseolus vulgaris L.) and several crops worldwide. The present investigation was carried out to introduce some antagonistic microorganisms as novel antifungal substances to be an alternative and secure method to effectively control the disease. Three Streptomyces species, i.e., S. griseus (MT210913 “DG5”), S. rochei (MN700192 “DG4”), and S. sampsonii (MN700191 “DG1”) were isolated, biologically, molecularly characterized, and evaluated in vitro and in vivo. Molecularly, polymerase chain reaction (PCR) amplification and nucleotide sequencing were used to characterize the pathogen and bio-agents. PCR amplification of the pathogen and Streptomyces species (bioagents) exhibited amplicons of around 535 bp and 1300 bp, respectively. The nucleotide sequence analysis of the three Streptomyces spp. indicated that S. rochei was closely related to S. griseus, and both had a distance relationship with S. sampsonii. The evaluation of bioagents was carried out against S. sclerotiorum. Reduction percentages in the mycelial growth of the pathogen ranged between 60.17 and 52.30%, indicating that S. rochie gave the highest inhibition percent. Incorporations of Streptomyces spp. culture filtrate components into culture media proved that S. sampsonii was more efficient as a bioagent in reducing mycelial growth pathogen by 84.50%. The effectiveness of the bioagent volatile compounds inhibited the pathogen growth at a rate of 54.50-72.54%, respectively, revealing that S. rochei was the highest inhibitor followed by S. griseus. The parasitic activity of Streptomyces spp. upon S. sclerotiorum showed deformation, contraction, and collapse when observed by light and scanning electron microscopy. Molecular characterization of the 3 Streptomyces spp. revealed that S. griseus was closely related to S. sampsonii (96%), secondly ranked by S. rochei (93.1%). Viability and germination of pathogen sclerotia were reduced when they dipped into the Streptomyces spore suspensions for 10, 20, and 30 days. Application of the 3 Streptomyces spp. in the field proved a great potential to control the disease. The results suggested that the 3 Streptomyces strains and their secondary metabolites can be potential biocontrol agents and biofertilizers for controlling S. sclerotiorum, the causative agent of bean white mold disease.

中文翻译：

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三个链霉菌的特性和潜在的抗真菌活性。作为抗菌核病菌（Sclerotiorum sclerotiorum）的生防剂

由霉菌核盘菌（Sclerotiorum sclerotiorum）这种毁灭性病原体引起的白霉病侵袭了四季豆（菜豆），并在全球范围内侵害了几种农作物。进行本研究以引入一些拮抗性微生物作为新型抗真菌物质，作为有效控制该疾病的替代性且安全的方法。分离了三种链霉菌种，即灰链霉菌（MT210913“ DG5”），罗氏链球菌（MN700192“ DG4”）和桑普森菌（MN700191“ DG1”），对其进行了生物学，分子表征并在体外和体内进行了评估。体内。在分子上，使用聚合酶链反应（PCR）扩增和核苷酸测序来表征病原体和生物制剂。病原体和链霉菌种（生物制剂）的PCR扩增分别显示出约535 bp和1300 bp的扩增子。三个链霉菌属的核苷酸序列分析。表明罗氏沙门氏菌与灰链霉菌密切相关，并且都与桑普森氏菌有距离关系。针对菌核链球菌进行了生物试剂的评估。病原菌菌丝生长的减少百分比在60.17和52.30％之间，这表明罗氏链球菌具有最高的抑制百分比。链霉菌属菌种的掺入。将培养液中的滤液成分培养到培养基中证明，桑普森酵母作为一种生物试剂可以将菌丝生长病原菌减少84.50％。生物制剂挥发性化合物的有效性分别以54.50-72.54％的速率抑制病原体的生长，这表明罗氏酵母是最高的抑制剂，其次是灰霉菌。链霉菌的寄生活性。在S. 当通过光和扫描电子显微镜观察时，菌核菌显示出变形，收缩和塌陷。3种链霉菌的分子表征。揭示出灰葡萄链球菌与桑普森链球菌（S. sampsonii，96％）密切相关，其次是罗氏链球菌（S. rochei，93.1％）。当将其浸入链霉菌孢子悬液中10天，20天和30天时，病原菌的活力和发芽力降低。3个链霉菌的应用。在现场证明了控制该病的巨大潜力。结果表明3株链霉菌及其次生代谢产物可能是潜在的生物防治剂和生物肥料，可防治豆腐霉菌的病原菌。3种链霉菌的分子表征。揭示出灰葡萄链球菌与桑普森链球菌（S. sampsonii，96％）密切相关，其次是罗氏葡萄球菌（S. rochei）（93.1％）。当将其浸入链霉菌孢子悬液中10天，20天和30天时，病原菌的活力和发芽力降低。3个链霉菌的应用。在现场证明了控制该病的巨大潜力。结果表明3株链霉菌及其次生代谢产物可能是潜在的生物防治剂和生物肥料，可防治豆腐霉菌的病原菌。3种链霉菌的分子表征。揭示出灰葡萄链球菌与桑普森链球菌（S. sampsonii，96％）密切相关，其次是罗氏链球菌（S. rochei，93.1％）。当将其浸入链霉菌孢子悬液中10天，20天和30天时，病原菌的活力和发芽力降低。3个链霉菌的应用。在该领域被证明具有控制该疾病的巨大潜力。结果表明3株链霉菌及其次生代谢产物可能是潜在的生物防治剂和生物肥料，可防治豆腐霉菌的病原菌。当将其浸入链霉菌孢子悬液中10天，20天和30天时，病原菌的活力和发芽力降低。3个链霉菌的应用。在现场证明了控制该病的巨大潜力。结果表明3株链霉菌及其次生代谢产物可能是潜在的生物防治剂和生物肥料，可防治豆腐霉菌的病原菌。当将其浸入链霉菌孢子悬液中10天，20天和30天时，病原菌的活力和发芽力降低。3个链霉菌的应用。在现场证明了控制该病的巨大潜力。结果表明3株链霉菌及其次生代谢产物可能是潜在的生物防治剂和生物肥料，可防治豆腐霉菌的病原菌。