Isolation of nematophagous fungus Arthrobotrys musiformis and observation of nematode predating process

Objective To isolate nematophagous fungus Arthrobotrys musiformis from substances associated with cattle and sheep, and observe the process of the fungus predating third-stage larvae of Haemonchus contortus and free-living nematode Caenorhabditis elegans.

Method A. musiformis was isolated using baited plate technique, and the dynamic processes of A. musiformis predating H. contortus and C. elegans were observed under scanning electron microscopy (SEM). A. musiformis isolate NPS045 was inoculated onto 20 g·L^-1 water agar plate covered with cellulose membrane on agar surface, incubated for four days, and then the nematodes were added to the plates. The samples containing nematodes and fungi were collected and observed at different time points after the two nematode species were captured.

Result SEM analysis showed that 5 hours after the two nematode species were added, A. musiformis produced predating structures and started to capture the nematodes. The third-stage larvae of H. contortus were penetrated by A. musiformis 22 hours after being caught, invasive hyphae grew out of the larval body after 56 hours, and the larvae were completely digested by 68 hours. C. elegans were penetrated by A. musiformis and clearly shrunk 14 h after being caught, seriously collapsed after 19 hours, and were completely digested by the 24th hour.

Conclusion Seventeen A. musiformis strains were isolated from 1 502 samples associated with cattle and sheep, and the prevalence of A. musiformis in total samples was 1.13%.