Uncovering microbial colonisation mechanisms of barley using Phytophthora palmivora
R. LE FEVRE (1), B. O'Boyle (1), M. Moscou (2), S. Schornack (1) (1) The Sainsbury Laboratory, Cambridge, United Kingdom; (2) The Sainsbury Laboratory, Norwich, United Kingdom

Filamentous plant pathogens apply different strategies to infect plant tissues. In some cases products of plant genes are essential for microbial colonisation. Identification of these genes is important for durable resistance breeding in crops - exemplified by mutations in barley Mlo, which confer robust resistance to Blumeria graminis f. sp. hordei.  It is unclear if overlapping or distinct mechanisms affect root infection. We use the oomycete pathogen Phytophthora palmivora to study microbial colonisation mechanisms in different plant tissues. P. palmivora is an aggressive, hemibiotrophic pathogen with a broad host range. It colonises leaves and roots of barley and in both tissues infection is characterized by transient biotrophy, with formation of haustoria, preceding a switch to necrotrophy. Barley accessions vary greatly in degree of susceptibility to P. palmivora and notably, there was no overall correlation between degree of root versus shoot susceptibility. This suggests variation in different genes influences host susceptibility above- and belowground. Additionally, we found that a leaf developmental gradient influences P. palmivora colonisation, with more extensive colonisation observed in mature leaf sectors. The mlo5 mutation attenuates P. palmivora infection, but in young leaf sectors. The barley - P. palmivora interaction represents a simple system to identify and compare genetic components governing quantitative colonisation in diverse barley tissues.

Abstract Number: P19-704
Session Type: Poster