Phytophthora hydrogena

Name and publication

Phytophthora hydrogena Yang and Hong (2014)

Yang X, Gallegly ME, and Hong C. 2014. A high-temperature tolerant species in Clade 9 of the genus Phytophthora: P. hydrogena sp. nov. Mycologia 106: 57–65.

Correspondence author: Xiao Yang


from Yang et al. (2014)




refers to the aquatic habitat where it was isolated


Type: UNITED STATES OF AMERICA, recovered from irrigation water of a nursery reservoir, Virginia, USA, Oct 2007; holotype: VTMH 14882 (Virginia Tech Massey Herbarium, Blacksburg, Virginia, USA) dried culture of isolate 46A3

Ex-type: 46A3 (ATCC MYA-4919)

Sequences for ex-type in original manuscript: 46A3: ITSrDNA KC249959, Cox 1 KC249962 (Kroon et al. 2004)

Ex-type in other collections

46A3 = ATCC MYA-4919 = 1 XY-2013 (Hong), P19968 (WOC/WPC), CPHST BL 129 (Abad), 46A3 (Yang)

Molecular identification

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

Phytophthora hydrogena isolate CPHST BL 129 (= P19968 WPC) = ITS rDNA MG865508, COI MH136902

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

Clade 9a

Morphological identification

adapted from Yang et al. (2014)

Colonies and cardinal temperatures

Colonies on V8-A with no distinctive pattern, colonies on PDA and MEA with slow growth. The minimum temperature for growth is 5°C, optimum 30°C, and maximum 37°C.

Asexual phase

Sporangia nonpapillate, persistent, ovoid, obpyriform, limoniform, and ellipsoid (45 μm long x 30 μm wide), commonly with a conspicuous basal plug, showing nested and extended internal proliferation in sporangiophore. Hyphal swellings on sporangiophores occasionally observed. Chlamydospores rarely produced (35 μm diam) and mostly in very old cultures.

Sexual phase

Heterothallic. Isolates do not produce sexual structures in single culture. Original publication indicates that formation of gametangia with A2 tester isolates of P. cambivora and P. cinnamomi show oogonia globose with golden to brown pigment (av. 41 μm diam), antheridia predominantly amphigynous, multiple paragynous antheridia occasionally associated with an oogonium; oospores mostly plerotic (av. 38 μm), sometimes aplerotic and eccentric.

Additional specimen(s) evaluated

Phytophthora hydrogena ex-type CPHST BL 129, duplicate of P19968 (World Phytophthora Collection)

Hosts and distribution

Distribution: North America (USA: VA)
Substrate: isolated from 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