PT  - JOURNAL ARTICLE
AU  - Matheus Baseggio
AU  - Matthew Murray
AU  - Di Wu
AU  - Gregory Ziegler
AU  - Nicholas Kaczmar
AU  - James Chamness
AU  - John P. Hamilton
AU  - C. Robin Buell
AU  - Olena K. Vatamaniuk
AU  - Edward S. Buckler
AU  - Margaret E. Smith
AU  - Ivan Baxter
AU  - William F. Tracy
AU  - Michael A. Gore
TI  - Genome-wide association study reveals an independent genetic basis of zinc and cadmium concentrations in fresh sweet corn kernels
AID  - 10.1101/2021.02.19.432009
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.02.19.432009
4099  - http://biorxiv.org/content/early/2021/02/20/2021.02.19.432009.short
4100  - http://biorxiv.org/content/early/2021/02/20/2021.02.19.432009.full
AB  - Despite being one of the most consumed vegetables in the United States, the elemental profile of sweet corn (Zea mays L.) is limited in its dietary contributions. To address this through genetic improvement, a genome-wide association study was conducted for the concentrations of 15 elements in fresh kernels of a sweet corn association panel. In concordance with mapping results from mature maize kernels, we detected a probable pleiotropic association of zinc and iron concentrations with nicotianamine synthase5 (nas5), which purportedly encodes an enzyme involved in synthesis of the metal chelator nicotianamine. Additionally, a pervasive association signal was identified for cadmium concentration within a recombination suppressed region on chromosome 2. The likely causal gene underlying this signal was heavy metal ATPase 3 (hma3), whose counterpart in rice, OsHMA3, mediates vacuolar sequestration of cadmium and zinc in roots, whereby regulating zinc homeostasis and cadmium accumulation in grains. Consistent with transgenic studies in rice, we detected an association of hma3 with cadmium but not zinc accumulation in fresh kernels. This finding implies that selection for low cadmium will not affect zinc levels in fresh kernels. Although less resolved association signals were detected for boron, nickel, and calcium, all 15 elements were shown to have moderate predictive abilities via whole- genome prediction. Collectively, these results help improve our genomics-assisted breeding efforts centered on improving the elemental profile of fresh sweet corn kernels.Competing Interest StatementThe authors have declared no competing interest.