The root microbiome and plant health

Date

Tuesday 14th June 2016

Time

12:30-13:30

Venue

CSIRO Black Mountain B1 Lecture Theatre

Speaker

Dr. Corné Pieterse (Faculty of Science, Utrecht University, the Netherlands).

Synopsis

Plants nurture a large community of plant growth-promoting rhizobacteria (PGPR) that provide them with essential services, such as enhanced mineral uptake, nitrogen fixation, growth promotion, and protection from pathogens. These plant microbiota are predominantly hosted by the root and can be selected for by the plant, e.g. via root exudates. Selected PGPR promote plant health by stimulating plant’s immune system, a phenomenon called induced systemic resistance (ISR). The molecular mechanisms underpinning ISR have been intensively studied in our lab using the interaction between the model plant Arabidopsis thaliana and the PGPR strain Pseudomonas fluorescens WCS417. ISR requires action of the plant hormones jasmonic acid and ethylene and is effective against a broad variety of pathogens and even insect herbivores. ISR is not associated with major changes in gene expression in foliar tissues. Instead, ISR-expressing leaves are primed for accelerated defence gene expression, which only becomes apparent after pathogen attack, providing a cost-effective mechanism of protection. In contrast to leaves, many defence-related genes become specifically suppressed locally in the roots, possibly to accommodate the mutualists. A gene regulatory module controlled by the root-specific transcription factor MYB72 is essential for both the onset of ISR and the production of phenolic compounds excreted in the rhizosphere to mobilize iron.

Speaker bio

Corné Pieterse studied Plant Breeding and Plant Molecular Biology at the Wageningen University where he graduated cum laude in 1988. He performed his PhD research in Wageningen on the molecular basis of pathogenicity of the potato late blight pathogen Phytophthora infestans. After obtaining his PhD degree in 1993, he moved to Utrecht University to join the lab of Prof. Kees van Loon. First as a post-doctoral fellow, and between 1998 and 2004 as an assistant professor in molecular phytopathology at the department of Biology. His research group pioneered research on unravelling the rhizobacteria-induced systemic resistance signalling pathway and the role of phytohormone crosstalk in the regulation of plant immunity. In 2013 he was elected as a member of the Royal Netherlands Academy of Arts and Sciences (KNAW). Since 2014 he is a Thomson Reuters Highly Cited Researcher (World’s top 1% in the field). Corné is Scientific Director of the Institute of Environmental Biology and Distinguished Professor of Plant-Microbe Interactions, the Faculty of Science, Utrecht University, the Netherlands and currently CSIRO Distinguished Visitor.