P-289 - Identifying Arabidopsis candidate genes in response to beneficial microbes using image-based phenotyping

Pseudomonas simiae WCS417 is a plant-beneficial microbe known to promote growth and induce systemic resistance in Arabidopsis thaliana. It colonizes the roots of Arabidopsis, triggering morphological changes in both shoot and root architecture. Previous studies using in vitro systems have shown that the magnitude of these phenotypic responses varies significantly among natural Arabidopsis accessions,  suggesting that plant genetic factors influence this interaction. In this study, we investigate the genetic basis of Arabidopsis shoot responses to WCS417 in a soil-based system.  Using the non-destructive, image-based, high-throughput phenotypic platform HELIOS at the Netherlands Plant Eco-Phenotyping Center (NPEC), we quantified a range of  Arabidopsis shoot traits in response to WCS417 across a genetically diverse panel of natural Arabidopsis accessions. To identify the genetic loci underlying these responses, we are conducting a Genome-Wide Association Study (GWAS). Our preliminary results show that WCS417 promotes plant growth in soil-grown Arabidopsis. We observed distinct growth responses among accessions, varying in both the timing and magnitude of the beneficial effects, highlighting genotype-specific differences in response to WCS417. The ongoing GWAS aims to pinpoint genetic loci associated with these phenotypic variations, offering new insights into the molecular mechanisms governing the Arabidopsis-WCS417 interaction.