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

Tamiru, A and Paliwal, R and Manthi, S J and Odeny, D A and Midega, C A O and Khan, Z R and Pickett, J A and Bruce, T J A (2020) Genome wide association analysis of a stemborer egg induced “call-for-help” defence trait in maize. Scientific Reports (TSI), 10 (1). ISSN 2045-2322

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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.

Item Type: Article
Divisions: Research Program : East & Southern Africa
Research Program : Genetic Gains
Uncontrolled Keywords: Genomics, Maize
Subjects: Others > Genetics and Genomics
Others > Maize
Depositing User: Mr Arun S
Date Deposited: 09 Aug 2020 14:22
Last Modified: 03 Sep 2020 03:38
Official URL:
Acknowledgement: This Research was supported by BBSRC grant BB/J011371/1. We gratefully acknowledge the financial support for icipe research by European Union, UK’s Department for International Development (DFID); Swedish International Development Cooperation Agency (Sida); the Swiss Agency for Development and Cooperation (SDC); Federal Democratic Republic of Ethiopia and the Kenyan Government. We thank CIMMYT and Prof Mathews Dida of Maseno University for supplying seed. We thank Amos Gadi and Silas Ouko for assistance with insect rearing and screen house operations.
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