Researchers discover genetic mechanism that may enhance yield in cereal crops

Researchers at the Donald Danforth Plant Science Center have identified a genetic mechanism that controls developmental traits related to grain production in cereals. Their findings are published in The Plant Cell journal. 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 maize, sorghum, switchgrass, and sugarcane.

In the study, the researchers 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. The new research showed that conversion of a spikelet to a bristle is determined early in inflorescence development and 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. These BR-dependent phenotypes therefore represent two potential avenues for enhancing grain production in millets, including subsistence crops in many developing countries that remain largely untapped for genetic improvement.

“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,” said lead researcher Andrea Eveland, assistant member at the Donald Danforth Plant Science Center. “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.”

The ultimate goal for Eveland’s team is to define targets for improving grain yield in cereals.

Study (pdf)