Pythium glomeratum, a new species isolated from agricultural soil taken in north-eastern France, its ITS region and its comparison with related species

Pythium glomeratum sp. nov. is described here. It was isolated from soil samples taken in the northern France in 1992, was wrongly identified as Pythium heterothallicum and was kept aside. Recently, the ITS region of the rDNA of this oomycete was amplified and sequenced. The differences between the sequence and a more detailed study of the morphological characters of these two species, revealed that both are related but different species. P. glomeratum is characterized by the presence of branched antheridia that wrap around the oogonia, aplerotic to almost plerotic oospores, and the lack of zoosporangia and zoospores. Taxonomical description of this new species, its comparison with related oomycetes, polymerase chain reaction (PCR) amplification of the internal transcribed region (spacers ITS1, ITS2, and the gene 5.8S) of its ribosomal nuclear DNA and the nucleotide sequence of this region are given here.