GWAS analysis of maize host plant resistance to western corn rootworm (Coleoptera: Chrysomelidae) reveals candidate small effect loci for resistance breeding

Authors: Washburn, Jacob; Lafond, Harper; LAPADATESCU, MARTIAN - University Of Missouri; PEREIRA, ADRIANO - University Of Missouri; ERB, MATTHIAS - University Of Bern; Hibbard, Bruce

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2023
Publication Date: 12/15/2023
Citation: Washburn, J.D., LaFond, H.F., Lapadatescu, M.C., Pereira, A.E., Erb, M., Hibbard, B.E. 2023. GWAS analysis of maize host plant resistance to western corn rootworm (Coleoptera: Chrysomelidae) reveals candidate small effect loci for resistance breeding. Journal of Economic Entomology. 116(6):2184–2192. https://doi.org/10.1093/jee/toad181.
DOI: https://doi.org/10.1093/jee/toad181

Interpretive Summary: Western corn rootworm (WCR) is the most serious North American insect pest of corn. It results in yield losses and management expenses of approximately 1-2 billion U.S. dollars annually. This study examined genetically diverse corn cultivars and used statistical methods to discover genes that confer native resistance to WCR. At least 16 genes with potential for use in future plant breeding efforts were discovered. These genes may be useful for breeders wanting to incorporate these traits into high yielding maize lines.

Technical Abstract: Western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is the most serious economic pest of maize, Zea mays, in the U.S. Corn Belt and threatens maize production in Europe. Traditional management options have repeatedly failed over time as WCR rapidly develops resistance to insecticides, transgenic maize and even crop rotation. Traits that improve host plant resistance and tolerance to pests are highly sought after by plant breeders to improve crop protection and pest management. However, maize resistance to WCR appears to be highly complex and despite over 75 years of breeding efforts, there are no naturally resistant hybrids available commercially. Using phenotypic data from field and greenhouse experiments planted with a highly diverse collection of 282 inbred lines, we screened and genetically mapped WCR-related traits to identify lines and genetic loci which may be useful for future breeding or genetic engineering efforts. Our results confirmed that WCR resistance is complex with relatively low heritability due in part to strong genotype by environment impacts and the inherent difficulties of phenotyping below ground root traits. The results of the Genome Wide Associated Study (GWAS) identified 29 loci that are potentially associated with resistance to WCR. Of these loci, 16 overlap with those found in previous transcription or mapping studies indicating a higher likelihood they are truly involved in corn WCR resistance. Taken together with previous studies, these results indicate that breeding for natural WCR resistance will likely require the stacking of multiple small effect loci.