Achlya catenulata C.L.A Pires-Zottarelli, A.L. Jesus, A.V. Marano & J.I. de Souza, 2015

Jesus, Ana Lucia De, Marano, Agostina V., De Souza, José I., James, Timothy Y., Jerônimo, Gustavo H., Rocha, Sarah C. O., Gonçalves, Danilo R., Boro, Marcela C. & Pires-Zottarelli, Carmen L. A., 2015, Achlya catenulata sp. nov., a new Saprolegniales (Oomycetes, Straminipila) from Brazilian mangrove swamp, Phytotaxa 212 (3), pp. 221-228 : 223-224

Achlya catenulata C.L.A Pires-Zottarelli, A.L. Jesus, A.V. Marano & J.I. de Souza , sp. nov. ( Fig. 1 A–E )

MB 811033

Holotype: — BRAZIL. São Paulo: Cananéia, Parque Estadual da Ilha do Cardoso, isolated from saline water, 29 August

2012, SP 465830 (dried culture), CCIBt 4029 and MMBF 01/15.

Ex-type: — BRAZIL. São Paulo: Cananéia, Parque Estadual da Ilha do Cardoso, isolated from freshwater, 04 June

2013, SP 465831 (dried culture), CCIBt 4030 and MMBF 02/15.

Monoecious. Mycelium dense; hyphae slender, sparingly branched. Sporangia abundant; fusiform or clavate;

straight; renewed sympodially; 230–460 × 20–30 μm. Spores discharge and behavior achlyoid; spore cluster persisting at exit orifice; encysted primary cysts 7.5–12.5 μm diam. Gemmae present, some catenulate. Oogonia abundant,

terminal or lateral; catenulate, chains of up to 11 oogonia, sometimes simple; obpyriform, 35.0–82.5 × 27.5–57.5 μm.

Oogonial wall pitted under region of attachment of the antheridial cells; smooth. Oogonial stalks straight, 1–2½ times the diameter of the oogonium in length. Oospheres generally not maturing. Oospores eccentric; spherical; 1–3 (–5) per oogonium, and never filling it; 15–35 μm diam.; germination not observed. Antheridial branches diclinous; slender;

frequently branched; persisting. Antheridial cell tubular or clavate; simple or branched; attached apically, laterally or by projections; fertilization tube present, persisting.

Etymology: ─ “catenulata ” refers to the presence of catenulate oogonia.

Specimens examined: — BRAZIL. São Paulo: Cananéia, Parque Estadual da Ilha do Cardoso , from a permanent lagoon at a mangrove swamp, 29 August 2012 (CCIBt 4029) ; Perequê river , 04 June 2013 (CCIBt 4030) .

Culture growth: —Colony without special pattern and limited growth. Growth of the isolates after 96 h at 21 ºC:

(i) CCIBt 4029: on MP 5 without salt: 2.2 cm; on MP 5 with 0.5 % of salt: 2.5 cm; on MP 5 with 1.0 % of salt: 1.4 cm; on MP 5 with 1.5, 2.0, 2.5 and 3.0 % of salt: no growth was observed; (ii) CCIBt 4030: on MP 5 without salt: 2.0 cm; on MP 5 with 0.5 % of salt: 2.6 cm; on MP 5 with 1.0 % of salt: 1.2 cm; on MP 5 with 1.5, 2.0, 2.5 and 3.0 % of salt: no growth was observed.

Notes:─Both isolates grew on Sorghum sp. seeds used as bait forming a limited two-week colony (1 cm). The zoosporangia are abundant and the zoospore discharge is exclusively achlyoid (from both primary and secondary zoosporangia) with persistent spore clusters at the exit pore ( Fig. 1A ), renewed sympodially ( Fig. 1B ). Gemmae are mainly produced in old cultures. Oogonia are formed abundantly in a catenulate fashion after two weeks ( Fig. 1C ). The oospores commonly failed to mature but when they mature are eccentric ( Figs. 1D, 1E ). The antheridial branches are exclusively diclinous and persistent ( Fig. 1C ). The isolates grew in solid culture media with a salinity range of 0.0–1.0 %. Although the isolate CCIBt 4029 was collected from nearly seawater conditions (2.8 % salinity), it did not grow in culture medium with higher saline concentrations than 1.0 %. The saline water was collected in a mangrove swamp where salt concentrations fluctuate throughout the day. Therefore, it might be able to tolerate saline conditions to some degree but it might not be able to grow and sporulate under these conditions.

Figures

FIGURE 1 A–E. Achlya catenulata.A.Achlyoid discharge of the zoosporangia. B. Sympodial renewal of the zoosporangia. C. Catenulate oogonia and diclinous antheridia. D–E. Oogonia, failed to mature and eccentric oospores and antheridia. Bars: 10 μm.