鄂尔多斯高原地区的黏细菌资源及其拮抗致病疫霉活性

Myxobacterium resources in Ordos Plateau: distribution and antagonistic activity against Phytophthora infestans

摘要:

【背景】黏细菌是一类可以产生丰富且结构新颖代谢产物的原核生物类群，在抗菌和抗肿瘤等方面存在应用价值。致病疫霉(Phytophthora infestans)是马铃薯晚疫病的致病菌，对马铃薯生产具有强大的破坏力。鄂尔多斯高原地区地理环境条件特殊，但该地区的黏细菌资源分布及其对马铃薯晚疫病菌的拮抗活性尚不清楚。【目的】探明鄂尔多斯高原地区可培养黏细菌资源的分布情况及其拮抗致病疫霉的活性，为黏细菌用于马铃薯晚疫病的防治奠定基础。【方法】采集内蒙古鄂尔多斯高原地区的46份土壤样品，分离、鉴定该地区的黏细菌资源，探究黏细菌分布与土壤类型、植被类型和环境因子之间的相关性，以及黏细菌拮抗致病疫霉的活性。【结果】该地区土壤干旱且肥力较差。从样品中共富集培养得到191个菌株，纯化102株，最终鉴定到65株黏细菌，分属于橙色黏球菌(Myxococcus fulvus)、变绿黏球菌(M. virescens)、弱小珊瑚球菌(Corallococcus exiguus)、Corallococcus interemptor、珊瑚状珊瑚球菌(C. coralloides)、匣状黏球菌(Pyxidicoccus fallax)、小原囊菌(Archangium minus)、过渡原囊菌(Ar. gephyra)和深褐色囊杆菌(Cystobacter fuscus) 5个属9个种，优势菌属为黏球菌属(Myxococcus)，优势菌种为M. fulvus和M. virescens。黏细菌较多分布于潮土和风沙土中，稀有黏细菌较多分布于灰钙土和栗褐土中。黏细菌的分布呈现出林地>耕地>草地>荒地的规律。89.40%的黏细菌菌株对致病疫霉有拮抗作用，拮抗菌株遍布所分离黏细菌的所有种，M. fulvus是高抗优势黏细菌菌种。【结论】鄂尔多斯高原地区具有丰富的黏细菌资源，该地区大部分黏细菌菌株具有拮抗致病疫霉的活性。本研究为开发基于黏细菌的新型拮抗马铃薯晚疫病的生物农药奠定了基础。

Abstract:

[Background] Myxobacteria are a group of prokaryotes producing abundant metabolites with novel structures, which endow myxobacteria with antimicrobial and antitumor activities.Phytophthora infestans is the pathogen causing potato late blight and has a destructive effect on potato production. The distribution of myxobacteria in Ordos Plateau as a special habitat and the antagonistic activity of these myxobacteria against P. infestans remain unclear. [Objective] To investigate the distribution of culturable myxobacteria and their antagonistic activity against P. infestans in the Ordos Plateau area, so as to lay a foundation for the use of myxobacteria in the prevention and control of potato late blight. [Methods] In this study, 46 soil samples were collected from Ordos Plateau of Inner Mongolia, from which myxobacteria were isolated and identified. The correlations of the distribution of myxobacteria with soil types, vegetation types, and environmental factors were determined, and the antagonistic activities of myxobacterial strains against P. infestans were examined. [Results] The soil in this area was dry and had poor fertility. Among the 191 strains cultured, 102 strains were purified, of which 65 strains were identified, belonging to 9 species of 5 genera, including Myxococcus fulvus, M. virescens, Corallococcus exiguus, C. interemptor, C. coralloides, Pyxidicoccus fallax, Archangium minus, Ar. gephyra, and Cystobacter fuscus. The dominant genus was Myxococcus, and the dominant species were M. fulvus and M. virescens. Myxobacteria were mainly distributed in fluvo-aquic soils and aeolian soils, while abundant rare species of myxobacteria were mainly distributed in sierozems and castano-cinnamon soils. Myxobacteria were the most common in woodland, which was followed by cultivated land, grassland, and wasteland. Among the isolated myxobacterial strains, 89.40% showed antagonistic effects on P. infestans. All the identified species had antagonistic strains, and M. fulvus was the dominant species with high resistance to P. infestans. [Conclusion] There are abundant myxobacterium resources in Ordos Plateau, and most myxobacterial strains in this area have antagonistic activity against P. infestans. This study lays a foundation for the development of novel agents from myxobacteria for the biocontrol of potato late blight.