罗布泊地区沙生植物根际放线菌多样性及生物活性的研究

Studies on diversity and bioactivity of rhizosphere actinomycetes from psammophyte in Lop Nor Region

目的研究罗布泊地区沙生植物根际放线菌多样性及其生物活性,以期发现新药用微生物资源。方法采用2种分离方法,6种分离培养基,从两种沙生植物24份根际土样中分离放线菌;对其中131株放线菌发酵液及乙酸乙酯提取液采用抗菌、杀线虫模型进行活性筛选,并根据活性测定结果结合菌株形态特征对其中66株进行16S rRNA基因序列分析。结果共分离到放线菌154株,53株在其中一个或两个活性筛选模型中都显示为阳性,总阳性率为40.46%,16S rRNA基因序列分析表明这66株放线菌分布在12个属,除了优势菌链霉菌(Streptomyces)外,还发现了拟诺卡氏菌属(Nocardiopsis),拟无枝酸菌属(Amycolatopsis),疣孢菌属(Verrucosispore),喜冷杆菌属(Cryobacterium),异壁放线菌属(Actinoalloteichus),假诺卡氏菌属(Pseudonocardia),普氏菌属(Prauserella),链单孢菌属(Streptomonospora),贫养杆菌属(Modestobacter),放线产孢菌属(Actinomycetospora),芽生球菌属(Blastococcus)等稀有放线菌属,菌株CA15-2与GenBank数据库中最近种Nocardiopsis nikkonensis YU1183-22T(GenBank登录号:AB491226)的相似性约为94%,可能为潜在的新属或新种。结论罗布泊地区沙生植物根际存在较为丰富的放线菌资源并能产生多种活性次级代谢产物,值得进一步的研究。

Objective To study the diversity and bioactivity of rhizosphere actinomycetes from psammophytes in Lop Nor region, Xinjiang, China. Methods Using two isolation methods, six different kinds of cultural media, 154 isolates were purfified from twenty four rhizosphere soil samples. 131 among 154 strains were cultured and both of their cultural broths and its organic extracts were assayed by antibacterial and nematicide model. Based on the morphological characteristics and biological activity, 66 strains were selected to carry out the 16S rRNA sequences test. Results 154 isolates were purified, 53 strains exhibited positive results in one or two screening model, the total positive rate was 40.46%. the 16S rRNA sequences test showed that the 66 strains belong to 12 different genera, including Streptomyces, Nocardiopsis, Amycolatopsis, Verrucosispore, Cryobacterium, Actinoalloteichus, Pseudonocardia, Prauserella, Streptomonospora, Blastococcus, Modestobacter and Actinomycetospora. The sequence similarity of strain CA15-2 with the described species of the nearest strain（YU1183-22T）in GenBank database was about 94%, which indicated strain CA15-2 may be a potential new species or new genus. Conclusion The studies demonstrated there are untapped actinomycetal resources at rhizosphere of psammophyte in Lop Nor region and its bioactive secondary metabolites deserved further exploration for microbial drugs.