Analyzing the Leaf Microbiome across 270 Diverse Maize Lines

 A largely unexplored area in global food security research is the interaction between crop plants and the microbial communities around them. The exceptions usually involve either diseases (e.g., rusts and blights) or a few specific symbioses (especially rhizobia and mycorrhiza). The general microbial community—the crop “microbiome”—nonetheless plays an important role in crop health. To better understand interactions between maize and its microbiome, we collected leaf samples from across ~270 diverse maize inbred lines to identify the genetic mechanisms that shape its microbial community. Community makeup was determined by targeted 16S amplification and deep sequencing. Several bacterial taxa show high heritabilities. Genome-wide association (GWAS) of these taxa identifies the major genetic loci influencing their abundance, and we identify recurring patterns across multiple associations. This is the most diverse maize microbiome study to date, and these results will direct future analyses to identify ways to manipulate the leaf microbiome to improve crop performance.