Sequencing the genomes of two critically-important biological control agents, the insect-killing nematodes Steinernema feltiae and Heterorhabditis bacteriophora
CSANR Project 125
Potatoes are a valuable Washington crop that is threatened by devastating insect pests. We have found (1) that insect-killing “entomopathogenic” nematodes (EPNs) are key natural enemies of these insects, and (2) that organic farming greatly increases EPN genetic diversity. Additionally, genetically-diverse mixes of EPN strains are more lethal to insects than any single worm strain. We would like to identify the specific genes that allow different EPN strains to “complement” one another in killing pests. Unfortunately, our efforts have been limited by the lack of well-constructed reference genomes for the two most common species of EPNs in Washington, Steinernema feltiae and Heterorhabditis bacteriophora. We propose to use the third-generation advanced sequencers now available at WSU and U Idaho (e.g., the PacBio RS and Illumina sequencers) to construct high-coverage genomes of these two species, and to compare gene-activity patterns within EPN pairs that complement one another in killing pest insects. Insect-killing nematodes can be used as bio-pesticides. Understanding the traits that make worms lethal to pests will allow us to design effective bio-pesticide blends, and to conserve and enhance beneficial nematode biodiversity on farms. Thus, our project will develop novel approaches to pest management that increase the sustainability of farming systems.
Jones, EI, Z Fu, DW Crowder, C Bates, R Jabbour, PA Hohenlohe, WE Snyder, and AA Elling. Manuscript. Emergent effects of intra- and inter-specific genetic diversity among natural enemies. To be submitted to Molecular Ecology.
Additional Funds Leveraged
Our ability to compete for federal funding was initially thwarted by our lack of a high-quality nematode genome, due to the difficulties described above that we have now overcome. An additional challenge in this past year was the decision by our key collaborator, Axel Elling, to move to an industry position and leave academics (and WSU). Nonetheless, we now have the necessary preliminary data in support of grant applications to one or more of the following funding sources: (1) USDA Foundational Program: Entomology and Nematology; (2) the USDA OREI and/or ORG programs; and (3) the NSF Ecology program.
Impacts and Outcomes
- Short-Term: We are producing detailed genomes for beneficial insect-killing nematodes, and identifying candidate genes that could explain why different strains of the same nematode species complement one another in killing hosts.
- Intermediate-Term: We will successfully compete for funding to further investigate these genetic differences; identify genes that correspond to important traits tied to a worm-strains ability to kill hosts and develop the means to search for these traits in nematodes in potato fields; and, design and test bio-pesticides that combine beneficial and complementary nematode traits.
- Long-Term: Provide new commercial bio-pesticides that effectively control potato beetles, while also providing a model approach for understanding why natural enemies complement one another that can be applied to other pests and/or cropping systems.