产生几丁质酶的交枝顶孢(Acremonium implicatum)对南方根结线虫生防潜力

 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18.49 μmol·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。

Biocontrol potential of chitinase-producing nematophagous fungus Acremonium implicatum against Meloidogyne incognita

Due to the recent environmental concerns of the nematicides, increasing amounts of research have been diverted to investigating natural fungi for the control of nematodes. To screen and identify fungi with chitinolytic and nematophagous activity, WLE1 fungal isolate was isolated from eggs of Meloidogyne hapla on tobacco of Wulian, Shandong, China. Based on the morphological and phylogenetic analysis, it was designated as Acremonium implicatum. The fungus was a chitinolytic-nematophagous microorganism. WLE1 chitinase activity reached the highest level of 18.49 μmol·h^-1·mL^-1 on the fourth day and then plateared until 16th day. The molecular weights of chitinase were estimated as 98.0 kDa, 82.9 kDa, 70.2 kDa, 35.9 kDa on SDS-PAGE analysis with 0.01 glycol chitin. Crude chitinase from A. implicatum caused lysis of the eggshell of M. incognita, and the inhibitory rate of eggs hatching achieved 80.17% on the 7th day following treatment. The fungus parasized in different life stages of M. incognita including eggs, the second juveniles and females. The rate of parasitism on eggs and the second juveniles of M. incognita were 82.11% and 73.97% on the 6th day after treatment,respectively. These results demonstrated that A. implicatum WLE1 with the strong chitinolytic and nematophagous activity had a great biocontrol potential against M. incognita.