Polydomus karssenii gen. nov. sp. nov. is a dark septate endophyte with a bifunctional lifestyle parasitising eggs of plant parasitic cyst nematodes (Heterodera spp.)

In this study a new taxon was investigated, which was previously isolated from eggs of the cereal cyst nematode Heterodera filipjevi, and roots of the brassicaceous plant species Microthlaspi perfoliatum. The phylogenetic relationships of all nematode and plant isolated strains with different geographic origins were studied using several loci including nuc rDNA ITS1-5.8S-ITS2 (internal transcribed spacer [ITS]), partial 28S nuc rDNA (28S), partial 18S nuc rDNA (18S), partial RNA polymerase II second-largest subunit (rpb2), and partial translation elongation factor 1-α (tef1). Polydomus karssenii gen. nov. sp. nov. (Ascomycota, Pleosporales, Phaeosphaeriaceae) is described and illustrated based on morphological and molecular phylogenetic evidence.