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Saprolegniaceae s.l. is a species-rich family of the monophyletic order Saprolegniales (Oomycota, Straminipila). Members of this family are primarily saprotrophs on cellulosic, chitinous, and proteinaceous materials in both aquatic and terrestrial ecosystems. This family also includes pathogens infecting various hosts, such as plants, crustaceans, and fishes at various life cycle stages. A diversity survey of Saprolegniaceae s.l. from freshwater and soil of the Brazilian Atlantic Rainforest resulted in 20 species isolated and identified through morphological and molecular analyses. These analyses revealed two new genera (Beakesia and Cokeria) and two new species, Achlya delicata and Brevilegnia milaneziana. Beakesia is proposed to accommodate Achlya catenulata, while Cokeria includes species with subcentric and centric oospores previously assigned to Achlya (A. racemosa, A. radiosa, and A. sparrowii). Our findings highlight the importance of additional sampling and studies in biodiversity-rich areas such as the Brazilian Atlantic Rainforest. They also provide a new perspective on the evolutionary relationships and nomenclatural delineation of traditional Oomycota genera, and revisit the family subdivisions of Saprolegniales, formally introducing Achlyaceae. [ABSTRACT FROM AUTHOR]

In this study, we isolated and identified oomycete species of the genus Saprolegnia. Saprolegnia atlantica, a new species isolated from soil and freshwater bodies in areas of the Atlantic Rainforest (São Paulo state, Brazil), is described herein based on morphology and phylogenetic analyses of combined ITS and LSU regions of the nuclear ribosomal DNA (nc rDNA). Taking into account the oospore type and/or the presence of terminal oogonia with androgynous antheridia, this new species appears to be related to S. litoralis and S. terrestris, but the phylogenetic placement of the isolates did not corroborate this relationship. Saprolegnia aenigmatica, S. blelhamensis, S. glomerata, and S. milanezii were also identified in the soil and submerged leaves, surface sediment, and/or water samples from freshwater bodies collected for the study. These specimens were sequenced, included in phylogenetic analyses, and described, commented and/or illustrated. Saprolegnia glomerata is a first report for Brazil, first sequences of S. blelhamensis and S. glomerata were deposited in GenBank, and Brazilian isolates of S. blelhamensis and S. glomerata are designated as epitypes. Our phylogenetic analyses of the Saprolegnia clade and previously published studies suggest that S. bulbosa, S. longicaulis, S. oliviae, and S. maragheica are new synonyms of S. ferax, and S. semihypogyna is a new synonym of S. eccentrica. [ABSTRACT FROM AUTHOR]