Identification of the MAT1 locus in Stagonosporopsis tanaceti, and exploring its potential for sexual reproduction in Australian pyrethrum fields.

Stagonosporopsis chrysanthemi, S. inoxydabilis, and S. tanaceti are closely related Ascomycetes associated with ray blight of the Asteraceae. To date, only S. tanaceti has been identified in Australia, incurring substantial losses to the pyrethrum industry. In contrast to the homothallic S. chrysanthemi and S. inoxydabilis, a sexual state has not been observed for S. tanaceti. The MAT1 locus in S. tanaceti was identified through de novo assembly of shotgun reads, and was further used to develop primers for amplification of the full-length MAT1/2 locus in S. chrysanthemi and S. inoxydabilis. As expected, S. chrysanthemi and S. inoxydabilis possessed a MAT1/2 locus typical of homothallic Dothideomycetes with two adjacent MAT1-1 and MAT1-2 idiomorphs. However, only MAT1-1 could be detected in the assembled genome of S. tanaceti. Although a sexual mode of reproduction cannot be ruled out for S. tanaceti, evidence so far suggests this is absent or occurring at very low frequency in Australian pyrethrum fields.

IMA Genome-F 4: Draft genome sequences of Chrysoporthe austroafricana, Diplodia scrobiculata, Fusarium nygamai, Leptographium lundbergii, Limonomyces culmigenus, Stagonosporopsis tanaceti, and Thielaviopsis punctulata.

The genomes of Chrysoporthe austroafricana, Diplodia scrobiculata, Fusarium nygami, Leptographium lundbergii, Limonomyces culmigenus, Stagonosporopsis tanaceti, and Thielaviopsis punctulata are presented in this genome announcement. These seven genomes are from endophytes, plant pathogens and economically important fungal species. The genome sizes range from 26.6 Mb in the case of Leptographium lundbergii to 44 Mb for Chrysoporthe austroafricana. The availability of these genome data will provide opportunities to resolve longstanding questions regarding the taxonomy of species in these genera, and may contribute to our understanding of the lifestyles through comparative studies with closely related organisms.