Name and publication

Phytophthora aquimorbida C.X. Hong (2012)

Hong CX, Richardson PA, Hao W, Shimire SR, Kong P, Moorman GW, Lea-Cox JD, and Ross DS. 2012. Phytophthora aquimorbida sp. nov. and Phytophthora taxon ‘aquatilis’ recovered from irrigation reservoirs and a stream in Virginia, USA. Mycologia 104: 1097–1108.

Corresponding author: chhong2@vt.edu

Nomenclature

from Hong et al. (2012)

Mycobank

MB513049

Etymology

“Aqui” refers to the habitat where it was isolated, and “morbida” refers to causing diseases.

Typification

Type: UNITED STATES OF AMERICA, Virginia, isolated from agricultural irrigation reservoirs, VPI [as 'VTMH'] 11739 dried culture from isolate 40A6 [Virginia Tech Massey Herbarium, Blacksburg, Virginia, USA]

Ex-type: culture ATCC MYA-4578 (40A6)

Sequences for ex-type in original manuscript: Phytophthora sp. CCH-2009b isolate 40A6: in table ITS rDNA: FJ666127; in text β-TUB GQ294534, CO1 GQ294536 and NADH1 GQ294538

Ex-type in other collections

(ET) CBS 149820, NRRL 64365, ATCC MYA-4578, CCH-2009b,  WPC P19964, S&T BL 128 (Abad), 40A6 (Hong)    

Molecular identification

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

Phytophthora aquimorbida isolate CPHST BL 128 (= P19964 WPC) = ITS rDNA MG783376, COI MH136847

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 aquimorbida CPHST BL 128
• NCBI: Phytophthora aquimorbida 40A6
• EPPO-Q-bank: Phytophthora aquimorbida 
• BOLDSYSTEMS: Phytophthora aquimorbida (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 Hong et al. (2012)

Colonies and cardinal temperatures

Colony colony:
assemblage of hyphae which usually develops form a single source and grows in a coordinated way
growth at 7 days in V8 agar, potato dextrose agar, malt extract agar slight rosette. The minimum temperature for culture growth is 5°C, with an optimum of 30°C, and a maximum of 40°C.

Conditions for growth and sporulation

Sexual structures and some hyphal swellings are produced in culture media including V8 agar. 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
are produced only in sterile soil water extract.

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
to ellipsoidal (28–68 μm long and 21–47 μm wide), borne on unbranched sporangiophores, some with nested or extended proliferationextended proliferation:
a type of internal proliferation in which the sporangiophore originates from inside of an empty sporangium, and continues to grow through and out of the old sporangium
. Hyphal swellings catenulatecatenulate:
having a chain-like form
and radiating are observed in some isolates. Chlamydospores absent.

Sexual phase

Homothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
smooth-walled, globoseglobose:
having a rounded form resembling that of a sphere
(24–41 μm diam) some with tapered basetapered base:
pertaining to the base of a sporangium or oogonium; funnel-shaped
, produced terminal, intercalaryintercalary:
positioned within a hypha (cf. terminal)
, or lateral; antheridia amphigynous amphigynous:
pertaining to the sexual stage in which the antheridium completely surrounds the stalk of the oogonium (cf. paragynous)
and are mostly seldom present; oosporesoospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
pleroticplerotic:
pertaining to an oospore that fills the oogonium (cf. aplerotic)
(29–36 μm diam).

Most typical characters

Phytophthora aquimorbida can be distinguished by the intercalaryintercalary:
positioned within a hypha (cf. terminal)
and lateral oogoniaoogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
sometimes with tapered basetapered base:
pertaining to the base of a sporangium or oogonium; funnel-shaped
.

Additional specimen(s) evaluated

Phytophthora aquimorbida CPHST-BL 128 (Abad) = P19964 [World Phytophthora Collection (WPC) California, USA], duplicate of the ex-type ATCC MYA-4578

Hosts and distribution

Distribution: Virginia, USA
Substrate: Phytophthora aquimorbida C.X. Hong was recovered from irrigation runoff reservoirs in Virginia.
Disease note:  Phytophthora aquimorbida is pathogenic on rhododendron plants and caused root discoloration, pale leaves, wilting, tip necrosis, and dieback.
Hosts: rhododendron

Retrieved January 19, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

 

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

 

 

• Google All Phytophthora aquimorbida
• Google Images Phytophthora aquimorbida
• Google Scholar Phytophthora aquimorbida

 

Fact sheet author

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