Jos M. Raaijmakers, Netherlands Institute of Ecology (NIOO-KNAW), Netherlands
Hosted by Nick Bouskill and Eoin Brodie
Jos Raaijmakers is head of the Microbial Ecology department of the Netherlands Institute of Ecology (NIOO-KNAW) and Professor at Leiden University, the Netherlands. The research program of his department aims to understand the diversity of microbial communities and microbial activities in terrestrial and aquatic ecosystems. Both systems ecology and reductionists’ approaches are adopted to identify biotic and abiotic factors involved in microbiome assembly and activity. Over the past decade, his research group has focused on how plant-associated microorganisms impact on plant root architecture, plant chemistry and tolerance to soil-borne pathogens.
Plants are colonized by an astounding number of microorganisms that can reach cell densities much greater than the number of plant cells. Various studies have shown that specific members of the plant microbiome can have profound effects on plant growth and development, nutrition and tolerance to diseases and abiotic stress. For the vast majority of plant-associated microbes, however, there is limited knowledge on the mechanisms involved in modulation of plant growth and health. Novel ‘omics technologies have provided more in-depth understanding of the diversity and functioning of the plant microbiome and significant advances are being made to uncover the multitrophic interactions on plant surfaces. To better understand this intriguing complexity, both systems ecology and reductionists’ approaches are needed to identify biotic and abiotic factors involved in microbiome assembly and activity. Here, new results are presented on how soil and rhizosphere bacteria impact on plant root architecture, plant chemistry and tolerance to soil-borne pathogens. We show that members of the y-Proteobacteria protect plants from pathogen infection by the production of chlorinated peptides and alter root architecture and plant growth via modulation of sulfur assimilation. For the β-Proteobacteria, comparative genomics, genetics, and chemical analyses revealed that specific volatile organic compounds (VOCs) affect plant growth and health. An overview will be given on the wealth of yet unknown functions of the plant microbiome and the striking similarities with the human microbiome.