Passari Ajit K, Mishra Vineet K, Gupta Vijai K, Saikia Ratul, Singh Bhim P
Molecular Microbiology and Systematics Laboratory, Department of Biotechnology, Aizawl, Mizoram University, Mizoram, India.
Molecular Glyco-biotechnology Group, Department of Biochemistry, National University of Ireland Galway, Galway, Ireland.
Pol J Microbiol. 2016 Aug 26;65(3):319-329. doi: 10.5604/17331331.1215611.
The prospective of endophytic microorganisms allied with medicinal plants is disproportionally large compared to those in other biomes. The use of antagonistic microorganisms to control devastating fungal pathogens is an attractive and eco-friendly substitute for chemical pesticides. Many species of actinomycetes, especially the genus Streptomyces, are well known as biocontrol agents. We investigated the culturable community composition and biological control ability of endophytic Streptomyces sp. associated with an ethanobotanical plant Schima wallichi. A total of 22 actinobacterial strains were isolated from different organs of selected medicinal plants and screened for their biocontrol ability against seven fungal phytopathogens. Seven isolates showed significant inhibition activity against most of the selected pathogens. Their identification based on 16S rRNA gene sequence analysis, strongly indicated that all strains belonged to the genus Streptomyces. An endophytic strain BPSAC70 isolated from root tissues showed highest percentage of inhibition (98.3 %) against Fusarium culmorum with significant activity against other tested fungal pathogens. Phylogenetic analysis based on 16S rRNA gene sequences revealed that all seven strains shared 100 % similarity with the genus Streptomyces. In addition, the isolates were subjected to the amplification of antimicrobial genes encoding polyketide synthase type I (PKS-I) and nonribosomal peptide synthetase (NRPS) and found to be present in most of the potent strains. Our results identified some potential endophytic Streptomyces species having antagonistic activity against multiple fungal phytopathogens that could be used as an effective biocontrol agent against pathogenic fungi.
与药用植物相关的内生微生物的前景相较于其他生物群落中的微生物而言极为广阔。利用拮抗性微生物来控制具有毁灭性的真菌病原体是一种有吸引力且环保的化学农药替代品。许多放线菌物种，尤其是链霉菌属，作为生物防治剂广为人知。我们研究了与乙醇植物锡兰青梅相关的内生链霉菌的可培养群落组成和生物防治能力。从选定药用植物的不同器官中总共分离出22株放线菌菌株，并筛选它们对七种真菌植物病原体的生物防治能力。七株分离物对大多数选定病原体表现出显著的抑制活性。基于16S rRNA基因序列分析对它们进行鉴定，强烈表明所有菌株都属于链霉菌属。从根组织中分离出的内生菌株BPSAC70对禾谷镰刀菌表现出最高的抑制率（98.3%），对其他测试真菌病原体也有显著活性。基于16S rRNA基因序列的系统发育分析表明，所有七株菌株与链霉菌属具有100%的相似性。此外，对分离物进行编码I型聚酮合酶（PKS-I）和非核糖体肽合成酶（NRPS）的抗菌基因扩增，发现大多数强效菌株中都存在这些基因。我们的结果鉴定出一些对多种真菌植物病原体具有拮抗活性的潜在内生链霉菌物种，它们可作为对抗致病真菌的有效生物防治剂。
