Miss Emily Marr

PhD student
01223 342612

Research title:

The genetic dissection of root system architecture in wheat

Climate change models project increases in drought incidence while soil nutrient losses contribute to environmental damage and lost profits (for example, N fertilisers represent ~30% of cereal production costs). It is estimated that global fertiliser production releases 575 million tonnes of greenhouse gases each year, and P fertilisers are made from finite reserves that may be exhausted in the next 50-100 years. Nutrient losses can be reduced and water capture increased by developing more resilient and efficient crop cultivars with improved root systems. However, root system architecture (RSA), the spatial configuration of roots in the soil, has often been overlooked in crop breeding due to the challenge of phenotyping organs below ground. Emily is exploring the genetic control of RSA with a particular focus on rooting angle, a trait that is associated with enhanced foraging. Using forward genetic screens, she is locating quantitative trait loci (QTL) in the doubled haploid Avalon x Cadenza wheat mapping population. She will determine the correlation between the traits of mature plants in the field and those of seedlings grown in pots.

Emily is investigating the potential interaction of the rhizosheath with RSA. The rhizosheath is the soil-polysaccharide complex that adheres to roots and is implicated in drought tolerance. Root exudates play a role in rhizosheath formation and certain polysaccharides are especially key for its formation. Through enzyme-linked immunosorbent assays (ELISA), she is characterising the exudate profile in lines of the Avalon x Cadenza population.

Soil microbes depend in part on the C and N supplied by root exudates and exert a significant effect on certain aspects of plant health, growth and development. There is a genotypic effect from the plant on rhizosheath formation and the rhizosphere microbial population, through root exudate deposition. She is sequencing the microbial profile of the rhizosphere of lines from the Avalon x Cadenza population as well as soil supplemented with purified plant polysaccharides. The work undertaken is pivotal for the characterisation of root pathway QTLs in wheat and will enhance the ability to harness the potential of roots for crop breeding.

Duration: October 2016-2020

Partners: NIAB, University of Cambridge

Funding: BBSRC (BBSRC DTP Programme)

Research projects:

Title: IWYP2: Rooty-A root ideotype toolbox to support improved wheat yields

Duration: November 2018 - October 2021

Partners: NIAB (lead), CIMMYT, Forschungszentrum Jülich, John Innes Centre, Justus Liebig University Giessen, University of Bologna, University of Queensland

Funding: BBSRC/IWYP/DFID (BB/S012826/1)


Fradgley, N., Evans, G., Biernaskie, J.M., Cockram, J.S., Marr, E.C., Oliver, A.G., Ober, E. and Jones, H., Effects of breeding history and crop management on the root architecture of wheat (2020), Plant and Soil 452: 587–600

Barlow, S.E., Wright, G.A., Ma, C., Barberis, M., Farrell, I.W., Marr, E.C., Brankin, A., Pavlik, B.M. and Stevenson, P.C., Distasteful nectar deters floral robbery (2017), Current Biology 27(16): 2552-2558