The fungal parasitoid, Hirsutella minnesotensis, is a dominant parasitoid of the soybean cyst nematode, which is a destruction pest of soybean crops. We investigated population structure and parasitism pattern in samples of H. minnesotensis in China to reveal the spreading pattern of this fungal species and the underlying mechanism generating the parasitization-related ability variability in Chinese population. In cross-inoculation experiments using different combinations of H. minnesotensis and soybean cyst nematode samples from China, most H. minnesotensis isolates fitted the criterion for "local versus foreign" parasitism profile, exhibiting local adaptation pattern to the SCN host. However, the genetic analysis of the single nucleotide polymorphisms with clone-corrected samples based on ten DNA fragments in 56 isolates of H. minnesotensis from China revealed that the Chinese H. minnesotensis population was a clonal lineage that underwent a founder event. The results demonstrated that the Chinese H. minnesotensis population had generated parasitization-related ability diversity after a founder event through individual variation or phenotypic plasticity other than local adaptation. The rapid divergence of parasitization-related abilities with simple genetic structure in Chinese H. minnesotensis population indicates a fundamental potential for the establishment of invasive fungal species, which is a prerequisite for biological control agents.
Bibliographical noteFunding Information:
This study was supported by the National Key Basic Research Program of China (program no. 973, Grant No. 2013CB127506 ), the National Natural Science Foundation of China (Grant No. 30800732 ), and the National Public Benefit Research Foundation of China (Grant No. 200903040 ). The authors thank Bruce Jaffee at the University of California, Davis, USA, for his constructive comments and International Science Editing for the editing, and Dr. Qiming Wang for his instructions on population genetics analyses.
- Ecological adaptation
- Invasive species
- Population bottleneck
- Soybean cyst nematode