The writeup for this research is in progress. It has not yet been submitted for peer review, or published as a preprint.
We investigated the genetic complexity of fungal pathogen resistance in a major crop pest and compared the genetic architecture of resistance to two distinct species of fungal pathogen. We also examined whether the underlying genetic differences that contribute to resistance were sensitive to host resource availability.
Summary
Helicoverpa armigera (Lepidoptera: Noctuidae) 2nd instar larvae from 103 outbred families were raised on a natural diet of either maize or soy, and exposed to either entomopathogenic fungi Beauveria bassiana (Bb1363), Metarhizium anisopliae (Ma425), or a control exposure in a factorial experiment design.
Larvae from each pathogen treatment replicate were put in rank order of susceptibility, and DNA from the most and least susceptible larvae, as well as randomly selected controls, was pooled for whole-genome sequencing. Single-nucleotide polymorphisms (SNPs) were tested for association with low pathogen susceptibility.
Comparison of the locations of candidate SNPs across all four host plant and pathogen treatments revealed the complex nature of fungal pathogen resistance and the importance of genotype by environment interactions (GxE) - SNPs associated with resistance to a given fungal pathogen on one host plant were not the same as those associated with resistance to either pathogen on the other plant.