Identifying Plant Genes Shaping Microbiota Composition in the Barley Rhizosphere

Abstract

AbstractA prerequisite to exploiting soil microbes for sustainable crop production is the identification of the plant genes shaping microbiota composition in the rhizosphere, the interface between roots and soil. Here we used metagenomics information as an external quantitative phenotype to map the host genetic determinants of the rhizosphere microbiota in wild and domesticated genotypes of barley, the fourth most cultivated cereal globally. We identified a small number of loci with a major effect on the composition of rhizosphere communities. One of those, designated the QRMC-3HS locus, emerged as a major determinant of microbiota composition. We then subjected soil-grown sibling lines harbouring contrasting alleles at QRMC-3HS and hosting contrasting microbiotas to comparative root RNA-seq profiling. This allowed us to identify three primary candidate genes, including a Nucleotide-Binding-Leucine-Rich-Repeat (NLR) gene in a region of structural variation of the barley genome. Our results provide novel insights into the footprint of crop improvement on the plant’s capacity of shaping rhizosphere microbes.