Novel loci underlie natural variation in vitamin E levels in maize grain

Authors: DIEPENBROCK, CHRISTINE - Cornell University; KANDIANIS, CATHERINE - Cornell University; LIPKA, ALEXANDER - Cornell University; MAGALLANES-LUNDBACK, MARIA - Michigan State University; VAILLANCOURT, BRIEANNE - Michigan State University; GONGORA-CASTILLO, ELSA - Michigan State University; WALLACE, JASON - Cornell University; CEPELA, JASON - Michigan State University; MESBERG, ALEX - Michigan State University; Bradbury, Peter; ILUT, DANIEL - Cornell University; MATEOS-HERNANDEZ, MARIA - Purdue University; HAMILTON, JOHN - Michigan State University; OWENS, BRENDA - Purdue University; TIEDE, TYLER - Purdue University; Buckler, Edward - Ed; ROCHEFORD, TORBERT - Purdue University; BUELL, ROBIN - Michigan State University; GORE, MICHAEL - Cornell University; DELLAPENNA, DEAN - Michigan State University

Submitted to: The Plant Cell
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2017
Publication Date: 10/2/2017
Citation: Diepenbrock, C., Kandianis, C., Lipka, A., Magallanes-Lundback, M., Vaillancourt, B., Gongora-Castillo, E., Wallace, J., Cepela, J., Mesberg, A., Bradbury, P., Ilut, D., Mateos-Hernandez, M., Hamilton, J., Owens, B., Tiede, T., Buckler IV, E.S., Rocheford, T., Buell, R., Gore, M., Dellapenna, D. 2017. Novel loci underlie natural variation in vitamin E levels in maize grain. The Plant Cell. 29(10):2374-2392. DOI: https://doi.org/10.1105/tpc.17.00475
DOI: https://doi.org/10.1105/tpc.17.00475

Interpretive Summary: Tocochromanols are lipid-soluble antioxidants --made by all plants --that are also consumed by humans, primarily in the form of seed oils. Some of these compounds have vitamin E activity, among other benefits to plant fitness and human and animal health. This study analyzed how genetics influence the levels of vitamin E in maize grain, a major food staple. Through our research, we identified 14 genes that influence the level of ocochromanolsvin maize grain. Understanding how these genes affect tocochromanols provides a clear path forward for breeding for vitamin E levels in maize grain, and perhaps also in other major cereals.

Technical Abstract: Tocopherols, tocotrienols, and plastochromanols (collectively termed tocochromanols) are lipid-soluble antioxidants synthesized by all plants. Their dietary intake, primarily from seed oils, provides vitamin E and other health benefits. Tocochromanol biosynthesis has been dissected in the dicot Arabidopsis thaliana, which has green, photosynthetic seeds, but our understanding of tocochromanol accumulation in major crops, whose seeds are nonphotosynthetic, remains limited. To understand the genetic control of tocochromanols in grain, we conducted a joint linkage and genome-wide association study in the 5000-line U.S. maize (Zea mays) nested association mapping panel. Fifty-two quantitative trait loci for individual and total tocochromanols were identified, and of the 14 resolved to individual genes, six encode novel activities affecting tocochromanols in plants. These include two chlorophyll biosynthetic enzymes that explain the majority of tocopherol variation, which was not predicted given that, like most major cereal crops, maize grain is nonphotosynthetic. This comprehensive assessment of natural variation in vitamin E levels in maize establishes the foundation for improving tocochromanol and vitamin E content in seeds of maize and other major cereal crops.