Predicting Lifestyle and Host From Positive Selection Data and Genome Properties in Oomycetes

Abstract

Background: Host and niche shifts are a source of genomic and phenotypic diversi_cation as evidenced in parasitism. Most characteristic is core metabolism reduction as parasites adapt to a particular host, while the accessory genome often maintains a high degree of diversi_cation. However, selective pressures acting on the genome of such organisms are not fully understood. Results: Here, we developed a comparative genomic approach to study underlying adaptive trends in oomycetes, a eukaryotic phylum with a broad range of economically important plant and animal parasitic lifestyles. Our analysis reveals converging evolution on biological processes for oomycetes inhabiting similar niches. We _nd that certain functions, in particular carbohydrate metabolism, transport, and signaling, are important for host and environmental adaption in oomycetes. Discussion: Given the high correlation of lifestyle to genome properties in our oomycete dataset and the convergent evolution of fungal and oomycete genomes, we have developed a model that predicts plant pathogen lifestyles with high accuracy. Understanding how genomes and selective pressures correlate with lifestyle may be crucial to identify new emerging diseases and pandemic threats.