Abstract:
BACKGROUND: The Botryosphaeriaceae are important plant pathogens, but also have the ability to establish
asymptomatic infections that persist for extended periods in a latent state. In this study, we used comparative
genome analyses to shed light on the genetic basis of the interactions of these fungi with their plant hosts. For this
purpose, we characterised secreted hydrolytic enzymes, secondary metabolite biosynthetic gene clusters and
general trends in genomic architecture using all available Botryosphaeriaceae genomes, and selected
Dothideomycetes genomes.
RESULTS: The Botryosphaeriaceae genomes were rich in carbohydrate-active enzymes (CAZymes), proteases, lipases
and secondary metabolic biosynthetic gene clusters (BGCs) compared to other Dothideomycete genomes. The
genomes of Botryosphaeria, Macrophomina, Lasiodiplodia and Neofusicoccum, in particular, had gene expansions of
the major constituents of the secretome, notably CAZymes involved in plant cell wall degradation. The
Botryosphaeriaceae genomes were shown to have moderate to high GC contents and most had low levels of
repetitive DNA. The genomes were not compartmentalized based on gene and repeat densities, but genes of
secreted enzymes were slightly more abundant in gene-sparse regions.
CONCLUSION: The abundance of secreted hydrolytic enzymes and secondary metabolite BGCs in the genomes of
Botryosphaeria, Macrophomina, Lasiodiplodia, and Neofusicoccum were similar to those in necrotrophic plant
pathogens and some endophytes of woody plants. The results provide a foundation for comparative genomic
analyses and hypotheses to explore the mechanisms underlying Botryosphaeriaceae host-plant interactions.
