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Abstract

Plant health is known to be significantly influenced by the microbial structure of the rhizosphere. Despite no formal terminology, a “bloom” can refer to an event where an individual rhizosphere taxon substantially increases in relative abundance within a defined period. Studies of pathogenic or growth-promoting rhizobacteria often place blooms in the context of increased root colonization and a subsequent plant phenotype. Less is understood concerning non-pathogenic blooms, especially among competing strains within the same genus. A non-pathogenic bloom of the genus Pseudomonas was observed by our group during a field study of the maize rhizosphere. To investigate the cause of this phenomenon, rhizosphere Pseudomonas genomes were assembled via shotgun metagenomics to assess their relative abundance at strain level. We identified

blooming species as P. brassicacearum, P. chlororaphis, and P. fluorescens. We will match these strains to genomes within our collection of 500 Pseudomonas isolated from the same maize field soil. A comprehensive pan-genome analysis will compare phylogenies, gene content, SNP variation, and growth rates between blooming and static genomes. Through this approach, we aim to identify genetic and molecular mechanisms that underlie differences in competitive fitness between individual Pseudomonas strains when colonizing the rhizosphere of maize.