Abstract: A strain 18-A-5 produced blue diffusible pigment was isolated from a tropical rainforest soil sample. Morphological observation showed that on Gause's synthetic agar medium the strain produced large quantities of blue diffusible pigment, blue substrate mycelium, grey-white aerial mycelium, grey spore, long spore chains straight or flexuous, spores were cylindrical and smooth. The genomic DNA G+C content of the strain was 62.4%. Analysis of the 16S rDNA gene sequence(GenBank accession no. EU054353) of strain 18-A-5 revealed that the highest similarity (100%) was to Streptomyces indigoferus ATCC23924^T and Streptomyces herbaricolor ATCC23924^T. Phylogenetic tree of Streptomyces 16S rDNA gene sequences showed that 18-A-5 strain was clustered with Streptomyces indigoferus and Streptomyces herbaricolor, the confidence branch was 74%.On the basis of its physiological and molecular properties, it is evident that the strain 18-A-5 belongs to Streptomyces herbaricolor. The physicochemical characterization of pigment was studied.

Key words: blue pigment, streptomycete, 16S rDNA, phylogenesis

摘要： 从原始热带雨林土壤中,分离到一株产蓝色色素菌株18-A-5,对其进行了系统分类学研究。形态学特征观察表明,在高氏合成一号培养基上初产蓝绿色色素,日久为深蓝色,基内菌丝蓝色,气生菌丝灰白色,产灰色孢子,孢子丝直或柔曲,形成长孢子链,孢子圆柱形。其DNA的G＋C摩尔分数为62.4%,16S rDNA序列分析结果(GenBank登陆号为EU054353),18-A-5与生靛链霉菌Streptomyces indigoferus ATCC23924^T 、草绿色链霉菌Streptomyces herbaricolor ATCC23924^T具有极高的同源性,达100％,聚类分析表明,18-A-5与生靛链霉菌Streptomyces indigoferus、草绿色链霉菌Streptomyces herbaricolor两株菌聚类在一起,分支置信度为74%。结合生理生化特性、细胞壁化学组成分析、脂肪酸分析等将菌株18-A-5定名为草绿色链霉菌Streptomyces herbaricolor。并对该蓝绿色可溶性色素性质进行了耐酸碱性、热稳定性、抗菌谱等初步分析。

关键词: 蓝色素, 链霉菌, 16S rDNA, 系统发育