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由于化学杀线剂给环境带来了污染问题,寄生线虫的生防真菌成为研究热点。为进一步鉴定和筛选高效食线虫真菌,从山东日照五莲烟草北方根结线虫卵中分离到1株较高应用潜力菌株WLE1。根据形态学和rDNA-ITS序列分析方法鉴定该菌为交枝顶孢Acremonium implicatum。该菌是1株能够产生几丁质酶的食线虫真菌,在第4天几丁质酶活性到达高峰,为18.49μmol·h-1·mL-1,直到第16天依然维持较高活性;活性电泳测定其几丁质酶分子量分别为98.0、82.9、70.2和35.9 kDa;交枝顶孢几丁质粗酶液处理南方根结线虫卵,第7天卵的孵化抑制率为80.17%。该菌能够寄生南方根结线虫卵、2龄幼虫和雌虫。第6天卵和2龄幼虫的寄生率分别为82.11%和73.97%。说明具有高效产生几丁质酶特性且能寄生南方根结线虫不同生活史阶段的交枝顶孢WLE1对南方根结线虫具有巨大生防潜力。
As the chemical nematicide brings pollution to the environment, parasitic nematodes biocontrol fungi become a research hotspot. To further identify and screen Echinochloa crusgalli, a higher potential strain WLE1 was isolated from the eggs of N. incognita in Wulian tobacco in Shandong province. The strain was identified as Acremonium implicatum according to morphology and rDNA-ITS sequence analysis. The strain is a nematophagous fungus capable of producing chitinase. The chitinase activity peaked at 18.49 μmol · h-1 · mL-1 on day 4, and maintained high activity on the 16th day. The molecular weight of chitinase was 98.0, 82.9, 70.2 and 35.9 kDa, respectively. The activity of chitinase was 80.17% on the seventh day. The bacteria can parasitize southern root knot nematode eggs, second instar larvae and females. The parasitism rates of eggs and 2nd instar larvae on the 6th day were 82.11% and 73.97% respectively. These results indicated that WLE1, which has the characteristics of efficiently producing chitinase and can parasitize different stages of life cycle of Meloidogyne incognita, has great potential of biocontrol against Meloidogyne incognita.