Name and publication

Phytophthora hydrogena X. Yang & C.X. Hong (2014)

Yang X, Gallegly ME, and Hong C. 2014. A high-temperature tolerant species in Cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
9 of the genus Phytophthora: P. hydrogena sp. nov. Mycologia 106: 57–65.

Correspondence author: Xiao Yang yxiao9@vt.edu

Nomenclature

from Yang et al. (2014)

Mycobank

MB803274

Etymology

refers to the aquatic habitat where it was isolated

Typification

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

(ET) NRRL 64262, ATCC MYA-4919, WPC P19968, 1 XY-2013 (Hong), S&T BL 129 (Abad), 46A3 (Hong)

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

Voucher sequences for Molecular Toolbox with seven genes (ITS, β-tub, COI, EF1α, HSP90, L10, and YPT1

(see Molecular protocols page) (In Progress)

Voucher sequences for Metabarcoding High-throughput Sequencing (HTS) Technologies [Molecular Operational Taxonomic Unit (MOTU)]

(see Molecular protocols page) (In Progress)

Sequences with multiple genes for ex-type in other sources

• NCBI: Phytophthora hydrogena CPHST BL 129
• NCBI: Phytophthora hydrogena 46A3
• EPPO-Q-bank: Phytophthora hydrogena 
• BOLDSYSTEMS: Phytophthora hydrogena (barcoding COI & ITS)

Position in multigenic phylogeny with 7 genes (ITS, β-tub, COI, EF1α, HSP90, L10, and YPT1)

Clade clade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
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

SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
nonpapillatenonpapillate:
pertaining to the production of a non-distinct, or inconspicuous, papilla at the distal end of the sporangium (cf. papillate and semipapillate)
, persistentpersistent:
pertaining to sporangia that remain attached to the sporangiophore and do not separate or detach easily (cf. caducous)
, ovoidovoid:
egg-shaped, with the widest part at the base of the sporangium and the narrow part at the apex
, obpyriformobpyriform:
inversely pear-shaped, i.e. with the widest part at the point of attachment (cf. pyriform)
, limoniform, and ellipsoidellipsoid:
refers to a solid body that forms an ellipse in the longitudinal plane and a circle in cross section; many fungal spores are ellipsoidal or elliptic
(45 μm long x 30 μm wide), commonly with a conspicuous basal plugbasal plug:
a plug protruding into a sporangium from the basal cross wall, separating it from the sporangiophore
, showing nested and extended internal proliferationinternal proliferation:
internal proliferation occurs when the sporangiophore continues to grow through an empty sporangium
in sporangiophore. Hyphal swellings on sporangiophores occasionally observed. ChlamydosporesChlamydospores:
an asexual spore with a thickened inner wall that is delimited from the mycelium by a septum; may be terminal or intercalary, and survives for long periods in soil
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 gametangiagametangia:
part of hypha specialized for fusion in sexual reproduction (see antheridium and oogonium)
with A2 tester isolates of P. cambivora and P. cinnamomi show oogoniaoogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
globoseglobose:
having a rounded form resembling that of a sphere
with golden to brown pigment (av. 41 μm diam), antheridiaantheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
predominantly amphigynousamphigynous:
pertaining to the sexual stage in which the antheridium completely surrounds the stalk of the oogonium (cf. paragynous)
, multiple paragynousparagynous:
pertaining to the sexual stage in which the antheridium is attached to the side of the oogonium (cf. amphigynous)
antheridiaantheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
occasionally associated with an oogoniumoogonium:
the female gametangium in which the oospore forms after fertilization by the antheridium
; oosporeoospore:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
s mostly pleroticplerotic:
pertaining to an oospore that fills the oogonium (cf. aplerotic)
(av. 38 μm), sometimes apleroticaplerotic:
pertaining to a mature oospore that does not fill the oogonium; i.e. there is room left between the oospore wall and oogonium wall (cf. plerotic)
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

 

• SMML USDA-ARS: Phytophthora hydrogena
• EPPO Global Database: Phytophthora hydrogena
• Forest Phytophthoras of the world: Phytophthora hydrogena
• CABI Digital Library: Phytophthora hydrogena
• Encyclopedia of Life (EOL): Phytophthora hydrogena
• Index Fungorum (IF): Phytophthora hydrogena

 

• Google All Phytophthora hydrogena
• Google Images Phytophthora hydrogena
• Google Scholar Phytophthora hydrogena

Fact sheet author

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Plant Pathogen Confirmatory Diagnostics Laboratory (PPCDL), United States of America.