Phytophthora brassicae

Name and publication

Phytophthora brassicae De Cock & Man in ’t Veld (2002)

Man in 't Veld WA, de Cock AWAM, Ilieva E, and Lévesque CA. 2002. Gene flow analysis of Phytophthora porri reveals a new species: Phytophthora brassicae sp. nov. Eur. J. Plant Pathol. 108: 51–62.

Corresponding author: w.a.man.in.’t.veld@pd.agro.nl

Nomenclature

from Man in 't Veld et al. (2002)

Mycobank

MB378137

Typification

Type: THE NETHERLANDS, from Brassica oleracea, CBS 179.87-H, in herb. dried culture

Ex-type: CBS 179.87

Sequences for ex-type in original manuscript: Phytophhtora brassicae CBS 179.87 = ITS rDNA AF380148

Ex-type in other collections

CBS 179.87 = P7517 (WPC), CPHST BL 8 (Abad), 61J8 (Yang)

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of the ex-type (see Molecular protocols page)

Phytophthora brassicae isolate CPHST BL 8 (= P7517 WPC) = ITS rDNA MG783384, COI MH136857

Sequences for ex-type in other sources
Position in ITS phylogenetic tree

Clade 8b

Morphological identification

adapted from Man in 't Veld et al. (2002)

Colonies and cardinal temperatures

Colonies on V8-A, PDA, and MEA with no distinct growth pattern, on PDA with slow growth. Cardinal temperatures for growth: minimum below 3°C, optimum 21°C, maximum 27°C.

Conditions for growth and sporulation

Sporangia abundantly produced in and on cornmeal agar as well as on hemp seeds in soil extract. Oogonia developed on cornmeal agar and V8 agar, only during a short period after isolation.

Asexual phase

Sporangia nonpapillate or semipapillate, persistent or caducous with short pedicel, globose to ovoid, sometimes distorted shapes, 25–48 × 40–74 μm, borne singly or in sympodial sporangiophore, occasionally laterally attached or intercalary. Hyphal swellings present in hemp-seed/water cultures, intercalary, often in chains and/or provided with radiating hyphae, occasionally terminal, (sub-) globose, 10–40 (–53) μm diam. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia terminal, wall smooth, inner side of the wall undulate, colorless to pale yellow, up to 2 μm thick (in some other isolates also dark yellow and up to 6 μm thick). Antheridia 1–2 per oogonium, mostly amphigynous, occasionally paragynous, variable in shape, 16–20 μm diam. Oospores aplerotic, wall up to 2 μm thick.

Most typical characters

Phytophthora brassicae is characterized by low cardinal temperatures for growth, the presence of semi- to nonpapillate sporangia, and caducous sporangia with short pedicels.

Additional specimen(s) evaluated

Phytophthora brassicae CPHST BL 8 (Abad) = P7517 [World Phytophthora Collection (WPC) California, USA]

Hosts and distribution

Distribution: Europe (UK, Germany), North America (USA: WI)
Substrate: leaves?
Disease note: storage rot (see Erwin & Ribeiro as Phytophthora porri)
Hosts: Brassica oleracea and Brassica sinensis (Brassicaceae)

Retrieved January 29, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

Fact sheet author

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Beltsville Laboratory, United States of America