摘 要 为从海南野生阿宽蕉居群根际土壤中筛选出具有较高酶活的产纤维素酶的放线菌，并对其进行分子鉴定，从而探索阿宽蕉居群根际土壤产纤维素酶的潜力。从海南不同的野生阿宽蕉居群采集7份根际土壤，采用GA培养基和HV培养基进行选择性分离放线菌，采用刚果红染色法对分离得到菌株进行产纤维素酶活性筛选，并对具有活性的菌株进行16S rRNA鉴定，以确定其分类地位。结果表明：从7份野生阿宽蕉根际土壤中共分离得到210株放线菌。其中，55株菌具有纤维素酶活性，12株菌表现出强活性。16S rRNA基因序列分析结果表明，它们属于放线菌纲下5个亚目6个科8个属，分别为链霉菌属、小单孢菌属、野野村氏菌属、疣孢菌属、戈登氏菌属、假诺卡氏菌属、拟诺卡氏菌属和球孢囊菌属，其中链霉菌属、小单菌属和野野村氏菌属为优势菌属。菌株X2303、X2502和X2733与已知菌的序列相似率最高，分别为98.52%、98.79%和99.11%，可能分别为链霉菌属、戈登氏菌属和疣孢菌属潜在的新分类单元。具有最高纤维素酶活性的菌株X2407为链霉菌，其与Streptomyces iranensis的16S rRNA基因序列相似率最高，为99.64%，具有较高的开发价值和应用前景。所以，海南野生阿寬蕉根际土壤中存在产纤维素酶的放线菌资源，主要以链霉菌为主。阿宽蕉根际土壤中存在一些新的放线菌分类单元。
关键词 香蕉 ；放线菌 ；纤维素酶 ；多样性
中图分类号 S668.1 ；Q936 文献标识码 A Doi：10.12008/j.issn.1009-2196.2018.09.012
Abstract Actinobacteria producing cellulase in the rhizospheric soil of Musa itinerans in Hainan was isolated and identified by using 16S rRNA gene sequences to explore potential cellulase resources from those habitats. Seven rhizospheric soil samples were collected from M. itinerans populations in Hainan. GA and HV media were used to isolate actinobacteria selectively. The cellulase-producing activities of the isolated strains were screened and preliminarily identified by using 16S rRNA. The results showed that a total of 210 actinobacterial strains were isolated， of which 55 strains had cellulase activity and 12 strains showed strong activity. The results of 16S rRNA gene analysis showed that these strains belonged to 5 suborders， 6 families and 8 genera. These 8 genera included Streptomyces， Micromonospora， Nonomuraea， Verrucosispora， Gordonia， Pseudonocardia， Nocardiopsis and Sphaerisporangium， of which Streptomyces， Micromonospora and Nonomuraea were dominant cellulase-producing genera. Strains X2303， X2502 and X2733 were similar to the known bacteria in sequence， and their similarities were 98.52%， 98.79% and 99.11%， respectively. The Strains X2303， X2502 and X2733 are potential new taxonomic units for Streptomyces， Gordonia and Verrucosispora， respecitvely. The Strain X2407 belonged to Streptomyces which showed the highest cellulase activity， and it had the highest similarity （99.64%） of 16S rRNA gene sequence to Streptomyces iranensis. It had high value for development and application. Cellulase-producing actinobacteria resources in the rhizosphere soil of M. itinerans in Hainan were mainly under Streptomyces. Some new taxonomic units of actinobacteria were detected in the rhizosphere soil of M. itinerans.
Keywords banana ； actinobacteria ； cellulase ； diversity