Abstract
Pythium insidiosum is a pathogenic oomycete that infects humans and animals, causing
a fatal infectious disease, pythiosis. The number of reported pythiosis cases is increasing
worldwide, particularly in Thailand, where it is endemic. However, diagnosing and treating
pythiosis is challenging due to the lack of effective antifungal drugs or vaccines. Surgery to
remove the infected organ is often necessary, but many patients do not survive the infection.
To gain a deeper understanding of P. insidiosum and potentially discover new ways to detect
and control the pathogen, it is crucial to study its basic biology, diversity, evolution, and
pathogenesis. The genome of an organism contains vital information that distinguishes it from
others. Thus, a logical approach is to sequence and compare the genomes of P. insidiosum
and related species to identify genetic differences that contribute to their phenotypic diversity,
including traits like virulence and drug resistance.
In this study, we used the MGIseq2000 next-generation sequencing platform to
sequence the genomes of 27 P. insidiosum strains isolated from humans, animals, and the
environment. Additionally, we included the existing sequenced genomes to provide the most
comprehensive dataset of 75 genomes of this pathogen. We developed our in-house
bioinformatic software, "Gene Table," to facilitate comparative genomic analyses. This allowed
us to identify the core and species-specific genes of P. insidiosum. By conducting a
phylogenomic analysis of the core genes, we gained insights into its evolution. We also
identified hypothetical protein-encoding genes that could be potential targets for future
biology studies and clinical applications.
In summary, this project sequenced 27 P. insidiosum genomes and combined them
with available genome data, resulting in the most comprehensive genome database of this
pathogen. We developed an online comparative genomic analysis tool called "Pythium Gene
Table" to facilitate genomic comparison of these 101 oomycetes. Analyzing the genome
contents of various P. insidiosum strains and related species enhanced our understanding of
their biology, pathogenicity, and evolution. Many hypothetical protein-encoding genes have
been identified, some of which could serve as new diagnostic and therapeutic markers.
Additionally, this research project has fostered a research network among scientists from
various Thai institutions and is expected to lead to at least one international publication in
the near future.
