Phytophthora mississippiae

Name and publication

Phytophthora mississippiae Yang, Copes, and Hong (2013)

Yang X, Copes WE, and Hong C. 2013. Phytophthora mississippiae sp. nov., a new species recovered from irrigation reservoirs at a plant nursery in Mississippi. J Plant Pathol Microb 4: 1–7.

Corresponding author: Xiao Yang


from Yang et al. (2013)




refers to the state of Mississippi where this new species was isolated


Type: UNITED STATES OF AMERICA from irrigation water of a nursery reservoir, Mississippi, February, 2012, ATCC MYA-4946

Note: No reference to "permanently preserved in a metabolically inactive state" is indicated in the manuscript; see 2013 Nomenclatural Procedures FAQ (ICN/Melbourne Code) Mycologia (G. Abad 1-17-14).

Ex-type: 57J3

Sequences for ex-type in original manuscript: 57J3: ITS rDNA = KF112852, Cox1 = KF112860

Ex-type in other collections

57J3 = ATCC MYA-4946, P19994 (WOC/WPC), CPHST BL 126 (Abad), 57J3 (Yang)

Molecular identification

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

Phytophthora mississippiae isolate CPHST BL 126 (= P19994 WPC) = ITS rDNA MG865542, COI MH136935

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

Clade 6b

Morphological identification

adapted from Hong et al. (2013)

Colonies and cardinal temperatures

Colony morphology after 7 days of growth on potato dextrose agar and malt extract agar with light chrysanthemum pattern, and on V8A with no defined pattern with mycelia concentrated at the center of colony. Minimum growth temperature 5°C; optimum 25–30°C, and maximum 35°C.

Asexual phase

Sporangia nonpapillate, sometimes semipapillate; persistent; ovoid, obpyriform, ellipsoid (32 x 70 μm); showing nested and extended internal proliferation and produced in unbranched sporangiophores. Hyphal swellings elongated with irregular shapes, catenulate, or globose. Chlamydospores absent.

Sexual phase

Self-sterile. Sexual stage produced in pairings with Phytophthora cinnamomi, Phytophthora cryptogea, and Phytophthora nicotianae testers. Oogonia with ornamented walls with pigmented to golden-brown color at maturation, many oogonia with tapered bases (38 μm diam); antheridia amphigynous (14 x 20 μm), sometimes bi-cellular; oospores plerotic (34 μm diam).

Most typical characters

Phytophthora mississippiae is characterized by the presence of oogonia with ornamented walls and catenulated hyphal swellings.

Additional specimen(s) evaluated

Phytophthora mississippiae ex-type CPHST BL 126, duplicate of P19994 (World Phytophthora Collection), which is a duplicate of MYA-4946

Hosts and distribution

Distribution: North America (USA: MS)
Substrate: isolated from irrigation water

Retrieved January 31, 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