1株抗根结线虫红树林放线菌的筛选与鉴定

从红树林底泥中分离筛选具有抗线虫活性的放线菌,并对活性菌株进行分类鉴定。采用稀释平板法分离放线菌,采用24孔板液体筛选模型筛选具有抗线虫活性的菌株,并对活性菌株进行形态学和生理生化特征研究,测定其16S rDNA序列并进行系统发育分析。筛选得到1株具有杀线虫活性的菌株,编号为HA11090,该菌株发酵液在稀释20倍和40倍后,抗根结线虫校正死亡率分别为70.5%和65.0%。菌株HA11090的16S rDNA序列与Saccharopolyspora hirsuta subsp.kobensis和Saccharopolyspora jiangxiensis的相似性最高,分别为99.35%和99.27%,三者在系统发育树上聚为一个分支,形态和生理生化特征分析显示,菌株HA11090与Saccharopolyspora jiangxiensis基本一致,而与S.hirsuta subsp.kobensis差异较大。鉴定菌株HA11090为Saccharopolyspora jiangxiensis,其发酵液具有较强的抗根结线虫活性,值得进一步研究。

Screening and Characterization of Anti-Root-Knot Nematode Actinomycetes Strain from Mud under Mangrove(Rhizophora)Forest

An actinomycetes strain with anti-nematode activity was isolated from mud beneath mangrove （Rhizophora） forest and carried out its taxonomic classification. The strain was isolated with dilution-plate method and screened the strain with anti-nematode activities adopted 24-stomous plate fluid model. The active strain was studied by its morpho- logical and physiological and biochemical characteristics and phylogenetic analysis with 16S rDNA sequencing. The re- sults showed that a strain possessing nematode killing activity was screened and numbered as HA11090, and mortality rates of the fermentation of strain against root knot nematode were 70.5% and 65% on 20 times dilution and 40 times dilution. The highest 16S rDNA sequence similarity with Saccharopolyspora hirsuta subsp, kobensis was 99.35% , and S. fiangxiensis 99.27%. The phylogenetic tree showed that strain HA11090 formed a cluster in the branch with S. hirsuta subsp, kobensis and S. fiangxiensis. The characteristics of morphology and physiology of strain HAll090 basi- cally accorded with S. jiangxiensis, but had great difference with S. hirsuta subsp, kobensis. Therefore, strain HA11090 was identified as Saccharopolyspora fiangxiensis, and its fermentation broth possessed strong activity against root knot nematodes. And it was worthy to study further on.