First Report of Achlya oblongata Infection in Freshwater-Reared Asian Seabass Lates calcarifer.

In September 2014, a freshwater oomycete was first isolated from Asian Seabass Lates calcarifer fry that were reared in freshwater at a fish hatchery in Sabah, Malaysia. A fungal strain was isolated from infected fry by using glucose yeast extract (GY) agar. From morphological identification, the strain belonged to the genus Achlya based on the mode of zoospore release. Molecular phylogenetic analysis of the internal transcribed spacer region sequences from the strain showed high similarity (99-100%) to Achlya oblongata. The isolate was able to grow on GY agar incubated at 15-35°C, in GY broth adjusted to pH 3.0-11.0, and in up to 1.0% NaCl. This is the first report of Achlya infection in freshwater-reared Asian Seabass in Malaysia.

Achlya spiralis, a new aquatic oomycete with bent oogonial stalks, isolated from the Burgundian region of France.

Achlya spiralis sp. nov. was isolated from water samples collected in the river Tille in the Burgundian region of France. The new oomycete is described, illustrated and compared with related species of the genus Achlya. It is characterized by the presence of smooth-walled oogonia that are usually borne on bent or twisted oogonial stalks; mainly monoclinous, androgynous and diclinous antheridial branches and eccentric oospores which generally do not mature or mature after a long period of time. The internal transcribed spacer (ITS) region of its rRNA is comprised of 671 bases. The taxonomic description of this new species, its comparison with related oomycetes and the sequence of the ITS region of its rRNA are discussed here.

Achlya abortispora, a new oomycete isolated from water samples taken from a water reservoir in Morocco.

Achlya abortispora sp. nov. was found in water and floating organic matter taken form a dam near Rabat, Morocco. The new species is described and compared with other species of the genus. Distinguishing characteristics of A. abortispora are the production of long fusiform sporangia with achlyoid and aplanoid discharge of zoospores; smooth-walled spherical to club-shaped oogonia, which are usually lateral, but at times intercalary, containing 1 to 20 oospheres. The oogonia can also bear 1 to 5 appendages, which may indicate oogonial proliferation. Most of the oospheres do not mature and are thus abortive. The antheridial branches supplying the oogonia are predominantly diclinous, but at times these may be monoclinous and androgynous. Antheridial branches coil and wrap around the oogonia. Morphologic features of the oomycete and the sequence of the ITS region of its rDNA, as well as their comparison with related species, are discussed. This is the first report of the occurrence of a saprolegniaceous oomycete from Morocco.