Understanding the coordination of epidermal features in barley and wheat

Linsan Liu, Chiara Campoli, Alasdair Iredale, Runxuan Zhang, Alistair M. Hetherington, Verity C. Bonnell, Tracy Lawson, Tansy Chia, James Cockram, Sarah M. McKim
Division of Plant Sciences, University of Dundee, Nethergate, Dundee, DD1 4HN, Scotland, UK

To succeed on land, plants evolved an adaptive outer epidermis which secretes a protective, lipid-rich cuticle to prevent water loss and reflect radiation. The epidermis also contains cells with specialised functions, including stomatal complexes controlling photosynthetic gas exchange and transpiration. In this way, epidermal specialisations finely balance protection from and exchange with the atmosphere. Engineering epidermal features helps optimise crop performance under changing climates. Since epidermal development and cuticle deposition are intertwined, we need to understand how these epidermal features are coordinated. We recently discovered that several barley eceriferum (Cer) genes control both epidermal patterning and cuticle properties, shedding light on a shared upstream network(s) controlling multiple epidermal features linked to cereal performance. In this project, we investigate the dynamics and control of these features in both wheat and barley. Our approach includes defining cuticular composition and structural changes during epidermal lineage progression, as well as tissue- and cell-scale transcriptomic changes, and how Cer genes modulate these events. We will explore how modifying cuticular deposition influences epidermal development and expand our epidermal network through reverse and forward genetic approaches. Overall, we will provide critical insights into the genetic, molecular and developmental basis underlying the coordination of epidermal features in grasses.