Dr Sarah McKim

How do different genes control crop performance?

Cereal grain provides more calories to the human diet than any other source. Grain yield is especially influenced by cereal growth and development as well as responses to the environment. Many of these traits were extensively modified during domestication and remain an important target of modern plant breeding. With the advent of molecular selection technologies and gene editing, defining the identity, mechanisms and interactions of the genes regulating cereal growth and development and environmental responses is vital to accelerate crop improvement.

Barley as a Model System

Barley is the fourth largest grown crop worldwide, and 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 plant development in the Triticeae. This is an exciting time to work in molecular crop genetics!

Barley Growth and Development

In contrast to animals, plant architecture is determined after embryogenesis as plants grow, develop and transition through vegetative and reproductive stages, defined by different architectures and surface features. For instance, 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.

In my research group, we examine several aspects of barley growth and development, focusing on gene function and mechanism, and how these regulatory pathways interact with the environment.

Our current work focuses on three topics:

1. How cereals regulate their epidermal surfaces to survive on land and the impact on agricultural productivity
2. How cereals control grain development and grain quality through an interplay between maternal tissue differentiation, endosperm growth and embryo maturation.
3. Resiliency mechanisms used by cereals to adjust their growth and development under extreme temperature and water limitation.

Impact

By deciphering gene function we will learn more about the genetic networks influencing plant architecture and apply this knowledge to molecularly-inform crop breeding.

Publications

Conserved signalling components coordinate epidermal patterning and cuticle deposition in barley. Liu, L., Jose, S. B., Campoli, C., Bayer, M. M., Sánchez-Diaz, M. A., Mcallister, T., Zhou, Y., Eskan, M., Milne, L., Schreiber, M., Batstone, T., Bull, I. D., Ramsay, L., von Wettstein-Knowles, P., Waugh, R., Hetherington, A. M. & McKim, S. M 2022

A gene encoding a SHINE1/WAX INDUCER1 transcription factor controls cuticular wax in barley Mcallister, T., Campoli, C., Eskan, M., Liu, L. & McKim, S. M. 2022. 

Cereal architecture and its manipulation. Annual Plant Reviews Dixon LE, van Esse W, Hirsz D, Willemsen V, McKim SM. 2022.