Characterization of the Teratosphaeria destructans Wingfield & Crous (1996) genome

Abstract

Whole genome sequencing is an increasingly favoured tool used to study plant pathogens. This has allowed for a dramatic decrease in the time and money required to identify and study various biological characteristics of pathogens, particularly mating strategy and population genetics. This study focused on a catastrophic eucalypt leaf and shoot pathogen, Teratosphaeria destructans, and aimed to elucidate the mating strategy of the pathogen and develop microsatellite markers for future population studies. The genomes of two T. destructans isolates from different geographic locations were sequenced and assembled. Local BLAST analyses revealed two distinct mating idiomorphs present at the mating type locus of T. destructans. The MAT1-1 idiomorph was found to possess a single mating type gene, the MAT1-1-1 gene, while the MAT1-2 idiomorph was found to harbour the MAT1-2- 1 gene as well as an additional mating type gene which has putatively been named MAT1- 2-12. PCR analysis of 16 isolates from North Sumatra, South Sumatra and South Africa using primers designed to amply fragments of these genes revealed that both mating types were found in both regions of Sumatra, while only a single mating type was identified in South Africa. These results show that T. destructans reproduces in a heterothallic manner, and is capable of doing so in North and South Sumatra, but not in South Africa. In order to develop microsatellite markers, both genomes and an additional genome from a South African isolate were mined for microsatellites. The resulting microsatellites were compared between the three isolates, and the polymorphic loci were extracted. Additionally, the presence of published microsatellites within the genomes was determined. Combined, these analyses yielded a total of 11 microsatellites that could be used to distinguish between the three isolates. Together, these results provide valuable insight into the biology of T. destructans, and will be of use when developing management and control strategies for this pathogen.