1株间座壳属真菌抗松材线虫的活性

Nematocidal Activity of Diaporthe sp. against Bursaphelenchus xylophilus

筛选对松材线虫(Bursaphelenchus xylophilus)有致死作用的内生真菌。从苦楝(Melia azedarach)健康组织(茎、叶、果实)中分离纯化内生真菌,菌株采用摇瓶培养,发酵液和菌丝体分别用乙酸乙酯萃取制备胞外和胞内代谢产物,采用浸渍法进行杀线虫活性筛选。共计分离纯化31株内生真菌,其中菌株J352-03的发酵液对松材线虫有显著的毒杀活性,在2 mg·mL^(-1)质量浓度下处理48 h,菌株J352-03胞内、胞外的次生代谢产物对松材线虫校正死亡率均达到100%,LC50值分别为0.46 mg·mL^(-1)、0.42 mg·mL^(-1);对松材线虫卵的孵化抑制率分别为66.54%、76.04%,松材线虫体内三磷酸腺苷酶(ATP酶)、过氧化氢酶(CAT)、乙酰胆碱酯酶(AChE)、超氧化物歧化酶(SOD)的活性显著低于对照组。菌株J352-03经形态学与rDNA-ITS序列分析鉴定为间座壳属一未知种Diaporthe sp.。综上所述,菌株J352-03对松材线虫有良好的生防潜力,具有进一步深入研究和开发利用的前景。

The endophytic fungi with lethal effect on Bursaphelenchus xylophilus was screened.The endophytes were isolated and purified from healthy tissues(twigs,leaves and fruits)of Melia azedarach.The strains were cultured in shake flask,the cultural broth and mycelium were extracted with ethyl acetate to prepare extracellular and intracellular products,respectively,and the screening of the nematocidal activity was conducted by immersion method.A total of 31 strains of endophytic fungi were isolated and purified from M.azedarach,in which one strain(J352-03)was found to exhibit significant nematocidal activity against B.xylophilus,intracellular and extracellular products caused 100%corrected mortality of B.xylophilus after 48 h exposure time at the concentration of 2 mg·mL^(-1),and the LC 50 values were 0.46 mg·mL^(-1) and 0.42 mg·mL^(-1) to B.xylophilus,respectively,the inhibition rate of eggs-hatching was 66.54%and 76.04%,the activities of adenosine triphosphatase(ATPase),catalase(CAT),acetylcholinesterase(AChE)and superoxide dismutase(SOD)in B.xylophilus were significantly lower than those in the control group.The strain J352-03 was identified as Diaporthe sp.by morphological observation and rDNA-ITS sequence analysis.In conclusion,the strain J352-03 has good biocontrol potential against B.xylophilus and has the prospect for further research,development and utilization.