A chitinolytic bacterium Chitinophaga sp. S167 producing extracellular chitinases was isolated from a soil sample in India. The extracellular chitinases produced by S167 were concentrated by ammonium sulphate precipitation (AS70) and seven bands corresponding to chitinases were observed by zymography. Optimum temperature and pH of AS70 were between 40 and 45 °C and pH 6.0 respectively with high stability at 20-40 °C and pH 5-7. AS70 inhibited the growth of Fusarium oxysporum, Alternaria alternata and Cladosporium sp. in vitro. The culture conditions for the high level production of extracellular chitinases were optimized resulting in 48-folds higher chitinase production. As the combination of chitinases could be more potent in biocontrol of plant diseases, it was checked if AS70 could control postharvest fungal infection caused by Fusarium oxysporum on tomatoes. AS70 treated tomatoes showed significant lower incidence of infection (11%) by F. oxysporum as compared with 100% in the control at 5 days post inoculation. Further, AS70 caused significant mortality in second stage juveniles of root knot nematode, Meloidogyne incognita, a major agriculture pest responsible for economic losses in agriculture. This study highlights the antifungal and nematicidal activity of chitinases produced by Chitinophaga sp. S167. To the best of our knowledge, this is the first report of the biocontrol potential of the chitinases produced by Chitinophaga sp.

中文翻译：

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由新分离的 Chitinophaga sp. 产生的几丁质酶的生物防治潜力。S167

几丁质分解细菌 Chitinophaga sp. 从印度的土壤样品中分离出产生胞外几丁质酶的 S167。S167产生的胞外几丁质酶经硫酸铵沉淀法(AS70)浓缩，酶谱法观察到与几丁质酶相对应的7条带。AS70的最适温度和pH分别在40-45°C和pH 6.0之间，在20-40°C和pH 5-7下具有高稳定性。AS70 抑制尖孢镰刀菌、链格孢菌和枝孢菌的生长。体外。优化了细胞外几丁质酶高水平生产的培养条件，使几丁质酶产量提高了 48 倍。由于几丁质酶的组合在植物病害的生物防治中可能更有效，检验AS70是否能控制番茄上由尖孢镰刀菌引起的采后真菌感染。在接种后 5 天，AS70 处理的西红柿显示出显着较低的尖孢镰刀菌感染发生率 (11%)，而对照组中的感染发生率则为 100%。此外，AS70 导致根结线虫 (Meloidogyne incognita) 的第二阶段幼虫大量死亡，根结线虫是造成农业经济损失的主要农业害虫。这项研究强调了几丁质酶产生的几丁质酶的抗真菌和杀线虫活性。S167。据我们所知，这是关于 Chitinophaga sp. 产生的几丁质酶的生物防治潜力的第一份报告。在接种后 5 天，尖孢菌与对照中的 100% 相比。此外，AS70 导致根结线虫 (Meloidogyne incognita) 的第二阶段幼虫大量死亡，根结线虫是造成农业经济损失的主要农业害虫。这项研究强调了几丁质酶产生的几丁质酶的抗真菌和杀线虫活性。S167。据我们所知，这是关于 Chitinophaga sp. 产生的几丁质酶的生物防治潜力的第一份报告。在接种后 5 天，尖孢菌与对照中的 100% 相比。此外，AS70 导致根结线虫 (Meloidogyne incognita) 的第二阶段幼虫大量死亡，根结线虫是造成农业经济损失的主要农业害虫。这项研究强调了几丁质酶产生的几丁质酶的抗真菌和杀线虫活性。S167。据我们所知，这是关于 Chitinophaga sp. 产生的几丁质酶的生物防治潜力的第一份报告。