Genome wide association analysis of a stemborer egg induced “call-for-help” defence trait in maize

• Published in: Scientific reports 2020-07, Vol.10 (1), p.11205-11205, Article 11205
• Main Authors: Tamiru, Amanuel, Paliwal, Rajneesh, Manthi, Samuel J., Odeny, Damaris A., Midega, Charles A. O., Khan, Zeyaur R., Pickett, John A., Bruce, Toby J. A.
• Format: Article
• Language: English
• Subjects: 631/114; 631/158; 631/181; 631/208; 631/337; 631/449; 631/45; 631/601; 631/61; 631/92; 639/638; 704/158; Allelochemicals; Animals; Association analysis; Bioassays; Biosynthesis; Chilo partellus; Corn; Cotesia sesamiae; Cyclopentanes - metabolism; Egg laying; Eggs; Genetic variability; Genome-wide association studies; Genome-Wide Association Study; Genomes; Genotypes; Genotyping; Germplasm; Herbivory; Herbivory - physiology; Humanities and Social Sciences; Hybrids; Inbreeding; Kinases; Moths - anatomy & histology; Moths - parasitology; Moths - physiology; multidisciplinary; Natural enemies; Oviposition; Oxylipins - metabolism; Pest resistance; Plant breeding; Plant Defense Against Herbivory - genetics; Protein kinase; Science; Science (multidisciplinary); Seeds - genetics; Seeds - metabolism; Signal transduction; Single-nucleotide polymorphism; Tri-trophic interactions; Volatile Organic Compounds - metabolism; Volatiles; Wasps - physiology; Zea mays; Zea mays - parasitology; Zea mays - physiology
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-68075-2

Tritrophic interactions allow plants to recruit natural enemies for protection against herbivory. Here we investigated genetic variability in induced responses to stemborer egg-laying in maize Zea mays (L.) (Poaceae). We conducted a genome wide association study (GWAS) of 146 maize genotypes comprising of landraces, inbred lines and commercial hybrids. Plants were phenotyped in bioassays measuring parasitic wasp Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) attraction to volatiles collected from plants exposed to stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) eggs. Genotyping-by-sequencing was used to generate maize germplasm SNP data for GWAS. The egg-induced parasitoid attraction trait was more common in landraces than in improved inbred lines and hybrids. GWAS identified 101 marker-trait associations (MTAs), some of which were adjacent to genes involved in the JA-defence pathway ( opr7, aos1, 2, 3 ), terpene biosynthesis ( fps3, tps2, 3, 4, 5, 7, 9, 10 ), benzoxazinone synthesis ( bx7, 9 ) and known resistance genes (e.g. maize insect resistance 1, mir1 ). Intriguingly, there was also association with a transmembrane protein kinase that may function as a receptor for the egg elicitor and other genes implicated in early plant defence signalling. We report maize genomic regions associated with indirect defence and provide a valuable resource for future studies of tritrophic interactions in maize. The markers identified may facilitate selection of indirect defence by maize breeders.