Dr Sarah McKim
Plant Sciences, School of Life Sciences
+44 (0)1382 385398
James Hutton Institute
Genetic Mechanisms underlying Cereal Architecture
Cereal grain provides more calories to the human diet than any other source. Grain yield is especially influenced by a cereal’s architecture or body plan. In fact, fundamental changes in body plan were hallmark events in cereal domestication. Modern plant breeding continues to select for better yielding crop architectures; however, we still know relatively little about how different genes work together at a molecular level to control cereal body plans, especially in the Triticeae, such as wheat, barley and rye.
See figure 1 below
Barley as a Model System
I am a plant developmental biologist with extensive experience in Arabidopsis thaliana and its close relatives. I am translating these approaches into crops by using barley as a model. Barley, the fourth largest grown crop worldwide, is a diploid, self-pollinating plant. Recent generation of sophisticated genomic resources enables us to combine the genetic utility of barley with molecular approaches to learn about developmental mechanisms underlying architecture in the Triticeae. This is an exciting time to work in molecular crop genetics!
See figure 2 below
In contrast to animals, plant architecture is determined after embryogenesis as plants grow, develop and transition through vegetative and reproductive stages. Vegetative phases involve leaf and shoot production while the reproductive phase promotes development of a flower-bearing inflorescence often borne on an elongated stalk. In barley, the inflorescence develops as a terminal spike. Nodes along the central spike stem (rachis) initiate rows of reproductive units called spikelets, each of which can develop into a single kernel of grain.
Developmental phase transitions are controlled by antagonistic activities between two microRNA (miRNA) families that negatively regulate the activity of specific transcription factors. These miRNAs and transcription factors appear deeply conserved across plants and are conspicuously represented in factors regulating agronomically important traits. We are keen to learn how these transcription factors control stage-specific morphologies and architectures in barley and Arabidopsis and the role of miRNA regulation in this process. Given its intimate association with grain production, we are especially interested in growth, development and presentation of the spike.
See figure 3 below
By deciphering gene function we will learn more about the genetic networks influencing plant architecture and apply this knowledge to molecularly-inform crop breeding.
Professor Hari Hundal and Dr Sarah McKim were named winners in their respective categories.
Dr Sarah McKim from the Division of Plant Sciences has been awarded tenure.
The productivity of cereal crops could get a boost in the future thanks to the discovery of new roles for a master gene regulator that influences the development of barley florets.