Verma Vijay C, Gond Surendra K, Kumar Anuj, Mishra Ashish, Kharwar Ravindra N, Gange Alan C
Mycopathology and Microbial Technology Laboratory, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India.
Microb Ecol. 2009 May;57(4):749-56. doi: 10.1007/s00248-008-9450-3. Epub 2008 Oct 14.
Endophytic actinomycetes from Azadirachta indica A. Juss. were screened and evaluated for their anti-microbial activity against an array of pathogenic fungi and bacteria. A total of 55 separate isolates were obtained from 20 plants, and 60% of these showed inhibitory activity against one or more pathogenic fungi and bacteria. Actinomycetes were most commonly recovered from roots (54.5% of all isolates), followed by stems (23.6%), and leaves (21.8%). The dominant genus was Streptomyces (49.09% of all isolates), while Streptosporangium (14.5%), Microbispora (10.9%), Streptoverticillium (5.5%), Sacchromonospora sp. (5.5%), and Nocardia (3.6%) were also recovered. Streptomyces isolates AzR 006, 011, and 031 (all from roots) had acute activity against Pseudomonas fluorescens, while AzR027, 032, and 051 (also all from roots) showed activity against Escherichia coli. Meanwhile, an isolate of Nocardia sp. from leaves (AzL025) showed antagonism against Bacillus subtilis. Overall, 32 of the 55 were found to have broad spectrum significant antimicrobial activity, while about 4% of them showed strong and acute inhibition to pathogenic fungi and bacteria. Isolates of Streptomyces AzR031, 008, and 047, Nocardia sp. AzL025, and Streptosporangium sp. AzR 021 and 048 are of particular interest because they showed significant antagonistic activity against root pathogens, including Pythium and Phytophthora sp. Thus, many of the isolates recovered from A. indica in this study may be used in developing potential bio-control agents against a range of pathogenic fungi and bacteria and in the production of novel natural antimicrobial compounds. These results not only further our understanding of plant-microbe interactions but also indicate that there is an untapped resource of endophytic microorganisms that could be exploited in the biotechnological, medicinal, and agricultural industries.
对印楝（Azadirachta indica A. Juss.）中的内生放线菌进行了筛选，并评估了它们对一系列致病真菌和细菌的抗菌活性。从20株植物中总共获得了55个单独的分离株，其中60%对一种或多种致病真菌和细菌表现出抑制活性。放线菌最常从根部分离得到（占所有分离株的54.5%），其次是茎部（23.6%）和叶片（21.8%）。优势属是链霉菌属（占所有分离株的49.09%），同时也分离到了孢囊链霉菌属（14.5%）、小双孢菌属（10.9%）、轮生链霉菌属（5.5%）、糖单孢菌属（5.5%）和诺卡氏菌属（3.6%）。链霉菌分离株AzR 006、011和031（均来自根部）对荧光假单胞菌具有强效活性，而AzR027、032和051（也均来自根部）对大肠杆菌表现出活性。同时，一株来自叶片的诺卡氏菌属分离株（AzL025）对枯草芽孢杆菌表现出拮抗作用。总体而言，55个分离株中有32个被发现具有广谱显著抗菌活性，其中约4%对致病真菌和细菌表现出强烈且强效的抑制作用。链霉菌AzR031、008和047分离株、诺卡氏菌属AzL025分离株以及孢囊链霉菌属AzR 021和048分离株特别值得关注，因为它们对包括腐霉属和疫霉属在内的根部病原体表现出显著的拮抗活性。因此，本研究中从印楝分离得到的许多分离株可用于开发针对一系列致病真菌和细菌的潜在生物防治剂，以及生产新型天然抗菌化合物。这些结果不仅加深了我们对植物 - 微生物相互作用的理解，还表明存在尚未开发的内生微生物资源，可在生物技术、医药和农业产业中加以利用。
