细菌JK JS3对松树线虫的杀线活性及菌种的分子鉴定

分离自马尾松的细菌JK JS3是对松材线虫(Bursaphelenchus xylophilus)具有较高杀线活性的拮抗细菌，为了解该菌株对松树体内其他植物线虫的杀线活性并验证经形态学和Biolog方法得到的菌种鉴定结果，笔者测定了该细菌培养滤液对大核滑刃线虫(Aphelenchoides macronucleatus)等7种松树体内植物线虫的杀线活性，并对该菌株的16SrDNA基因进行了扩增测序和比对分析。结果表明：该菌株培养液原滤液对测试线虫24h的杀线率均达到了100%，说明该细菌的杀线谱较广，但培养滤液的不同倍数稀释液对不同种线虫的杀线活性有显著差异，10倍稀释液对霍夫曼尼伞滑刃线虫(B.hofmanni)的杀线活性最高，杀死率为96.9%；其次对李氏长尾线虫(Seinura lii)，杀死率为73.7%；再次对松材线虫和拟松材线虫(B.mucronatus)，杀死率分别为48.7%和39.0%。而对大核滑刃线虫、吴氏长尾线虫(S.wuae)和外滑刃科线虫(Ektaphelenchidae sp.)的杀死率较低，分别为15%、1.5%和0；该菌株的16SrDNA基因序列BLAST比对结果表明，该菌株与菌株Bacillus amyloliquefaciens FZB42最为接近，相似性为99.86%，处于系统发育树的同一分支，进一步验证了其形态学和Biolog细菌鉴定仪的鉴定结果，确定该菌株的分类地位为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。

Nematicidal activities of the bacterium strain JK-JS3 on plant nematodes isolated from pine trees and its molecular identification

The bacterium strain JK-JS3 isolated from the leaves of Pinus massoniana has been screened for its high ne-maticidal activity on Bursaphelenchus xylophilus. The nematicidal activities of JK-JS3 on 7 plant nematodes isolated from different dead pine trees and its molecular identification have been studied in this paper. The bioassay result obtained from 24 hours treatment of JK-JS3 culture filtrate on different nematodes indicated that nematicidal activities not only effected on B. xylophilus, but also on other kinds of nematodes, the mortality of seven kinds of nematodes all attained 100% . The nematicidal activity of the ten times dilution of culture filtrate on B. hofmanni was the highest with mortality of 96.9% , the second was Seinura lii with 73. 7%. The mortality of B. xylophilus and B. mucronatus treated with ten times dilution of culture filtrate was 48. 7% and 39. 0% respectively, however, the mortality of Aphelenchoides macronu-cleatus, S. wuae and Ektaphelenchidae sp. were rather lower with 1.5%, 1.5% and 0 respectively. The result from 16SrDNA analysis of strain JK-JS3 indicated that the strain and Bacillus amyloliquefaciens FZB42 was at the same brand in the phylogenetic tree, their similarity was 99. 86% , and it confirmed the former identification by morphological characters and Biolog, which demonstrated the strain JK-JS3 belongs to Bacillus amyloliquefaciens.