Solving the world's food, feed and bioenergy challenges requires integration of multiple approaches and diverse skills, according to an announcement from the Donald Danforth Plant Science Center. Indeed, genomic studies have been augmenting many fields of study applicable to the agriculture and animal feeding industries.

For example, new research has identified genes that control vitamin E content in corn grain — a finding that could lead to improving the nutritional profile of this staple crop, according to an announcement from Cornell University.

Cornell scientists and colleagues from other institutions combined different types of genetic association analyses to identify 14 genes across the genome that were involved in the synthesis of vitamin E. Six genes were newly discovered to encode proteins that contribute to a class of antioxidant compounds called tocochromanols, collectively known as vitamin E.

Along with antioxidant properties, tocochromanols have been associated with good heart health in people and proper functioning in plants.

“We have established a near-complete foundation for the genetic improvement of vitamin E in grain of maize and other major cereals,” said Michael Gore, associate professor of plant breeding and genetics at Cornell and a co-corresponding author of the study published in the journal, The Plant Cell.

“There has been talk among breeders working to increase provitamin A in maize that we could increase vitamin E at the same time,” said first author of the paper Christine Diepenbrock, a graduate student in Gore’s lab. “They are related compounds biochemically, and tocochromanols are essential for seed viability in that they prevent seed oils from going rancid throughout seed storage, germination and early seedling development.”

The other co-corresponding authors are Dean DellaPenna, professor of biochemistry and molecular biology at Michigan State University, and Edward Buckler, research geneticist at the U.S. Department of Agriculture's Agricultural Research Service (ARS) and adjunct professor of plant breeding and genetics at the Institute for Genomic Diversity in Cornell’s Institute of Biotechnology.

Enhanced yield in cereal crops

Separately, Donald Danforth Plant Science Center assistant member Dr. Andrea Eveland and her team identified a genetic mechanism that controls developmental traits related to grain production in cereals. The work was performed in Setaria viridis, an emerging model system for grasses that is closely related to economically important cereal crops and bioenergy feed stocks such as corn, sorghum, switchgrass and sugarcane.

Her laboratory's research findings, "Brassinosteroids Modulate Meristem Fate & Differentiation of Unique Inflorescence Morphology in Setaria viridis," were recently published in the journal The Plant Cell.

In their study, Yang et al. mapped a genetic locus in the S. viridis genome that controls growth of sterile branches called bristles, which are produced on the grain-bearing inflorescences of some grass species. Their research revealed that these sterile bristles are initially programmed to be spikelets — grass-specific structures that produce flowers and grain. Eveland's work showed that conversion of a spikelet to a bristle is determined early in inflorescence development and is regulated by a class of plant hormones called brassinosteroids (BRs), which modulate a range of physiological processes in plant growth, development and immunity.

In addition to converting a sterile structure to a seed-bearing one, the research also showed that localized disruption of BR synthesis can lead to production of two flowers per spikelet rather than the single one that typically forms. Therefore, these BR-dependent phenotypes represent two potential avenues for enhancing grain production in millet, including subsistence crops in many developing countries that remain largely untapped for genetic improvement.

"This work is a great demonstration of how Setaria viridis can be leveraged to gain fundamental insights into the mechanisms that govern seed production in the grasses — our most important group of plants that includes corn, sorghum, rice, wheat and barley," said Dr. Thomas Brutnell, director of the Enterprise Institute for Renewable Fuels at the Danforth Center.

At the Danforth Center, Eveland's research focuses on the developmental mechanisms that control plant architecture traits in cereal crops. Specifically, she investigates how plant organs are formed from stem cells and how variation in the underlying gene regulatory networks can precisely modulate plant form.

"The genetics and genomics tools that are emerging for setaria enable more rapid dissection of molecular pathways such as this one and allow us to manipulate them directly in a system that is closely related to the food crops we aim to improve," Eveland said. "It means we are just that much closer to designing and deploying optimal architectures for cereal crops. The prospect of leveraging these findings for improvement of related grasses that are also orphan crop species, such as pearl and foxtail millets, is especially exciting."