Complete: Discovering the source of sugar beet infection and re-infection by rust and powdery mildew

Timescale: 2016 - 2017
Project Lead: Dr Matt Clark & Dr Mark McMullan
Project Sponsor: Earlham Institute and BBRO

Project Summary

Powdery mildew and rust can cause sugar yield losses of up to 20% and 14% respectively. Little is known about (1) the level of diversity of E. betae races, (2) the source of annual infection and (3) the races that re-infect after fungicidal treatment. Wild Beta could act as pathogen reservoirs, causing subsequent infection (and re-infection). In addition, these wild infections could be a source of novel virulence genes that overcome cultivar resistance. Therefore, it is important that a clearer understanding of mildew and rust population diversity to identify the causes of infection dynamics and improve future control strategies or resistance management.

Main Objectives

The ultimate aim of this project is to identify the source of fungal foliar infection of the sugar beet crop.  We hypothesize that wild sea beet could harbour pathogens which invade the agricultural system and provide a nursery for the evolution of novel effectors (as well as wild host resistant genes). Finding sugar beet pathogens on wild sea beet will also drive resistance gene research in future proposals.  To that end we set out to sequence the genome and conduct population genetics analyses of a mildew, Erysiphe betae and also sequence the genome of the rust, Uromyces beticola. This is because the genome of Erysiphe betae is expected to be smaller and less complex, making both assembly and analysis of more individuals feasible.

Outcomes / Key Message For Growers And Industry

  • New DNA extraction protocol applicable to many plant pathogens developed.

  • Preliminary data show that rust diversity in the UK appears to be low.

  • Preliminary data show differences between wild and agricultural beet rust pathogens is also low, suggesting that a single isolate could survive on both hosts.

  • Preliminary data show that we cannot rule out the potential for rust on wild hosts to invade the agricultural crop.

  • Preliminary results show us that wild beets may harbour pathogens that are important to consider when trying to understand how crop pathogens evolve.

  • We are still not clear about how wild and agricultural pathogens interact with each other but they appear to be closely related to one another.

  • Of fundamental importance to continued reduction of pathogen levels on crops, is to better define the interaction between wild and agricultural pathogens.

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BBRO is a not for profit making company.
We are set up jointly by British Sugar plc and the National Farmers' Union.

British Sugar
National Farmers' Union