Name and publication

Phytophthora riparia Reeser, W. Sutton & E.M. Hansen (2012)

Hansen EM, Reeser PW, and Sutton W. 2012. Phytophthora borealis and Phytophthora riparia, new species in Phytophthora ITS Cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
6. Mycologia 104: 1133–1142.

Corresponding author: hansene@science.oregonstate.edu

Nomenclature

from Hansen et al. (2012)

Mycobank

MB564287

Etymology

refers to the streams and adjacent soils of riparian forests where this species is found

Typification

Type: UNITED STATES OF AMERICA, from Oak Creek near Corvallis, Oregon; N44.566593, W-123.300984, collected April 2006, OSC 144,116, dried culture from OSU isolate VI 3-100B9F

Ex-type: MYA-4882 and CBS 132024 

Sequences for ex-type in original manuscript: VI 3-100B9F = ITSrDNA HM004225, β-tub JQ626618, Cox1 JQ626632 , Cox 2, 1 JQ626580

Ex-type in other collections

(ET) CBS 132024, ATCC MYA-4882,  WPC P19799, S&T BL 111 (Abad)

Molecular identification

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

Phytophthora riparia isolate CPHST BL 111 (= P19799 WPC) = ITS rDNA MG865583, COI MH136975

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 riparia CPHST BL 111 
• NCBI:  Phytophthora riparia 3-100B9F 
• EPPO-Q-bank: Phytophthora riparia
• BOLDSYSTEMS: Phytophthora riparia (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
6d

Morphological identification

adapted from Hansen et al. (2012)

Mycobank

Colonies and cardinal temperatures

Colony colony:
assemblage of hyphae which usually develops form a single source and grows in a coordinated way
morphology on PDA, V8, and MEA with chrysanthemum pattern. Minimum growth temperature 5°C, optimum 25–30°C, and maximum 35°C.

Conditions for growth and sporulation

Sporangia produced on plugs of culture media flooded in soil 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
, obpyriformobpyriform:
inversely pear-shaped, i.e. with the widest part at the point of attachment (cf. pyriform)
(45–65 L x 27–35 W µm); showing nested and extended internal proliferationinternal proliferation:
internal proliferation occurs when the sporangiophore continues to grow through an empty sporangium
; originated in unbranched sporangiophores. Hyphal swellings absent. 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
 absent.

Sexual phase

Sterile.

Most typical characters

Phytophthora riparia is characterized by the shape of the 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
, the type of proliferationproliferation:
formation of a sporangium within an empty sporangium that has previously emitted zoospores (internal or nested) or after the sporangiophore has emerged from the empty sporangium (external)
, and the sterile character of the sexual phase. 

Additional specimen(s) evaluated

Phytophthora riparia ex-type CPHST BL 111, duplicate of P19799 (World Phytophthora Collection)

Hosts and distribution

Distribution: North America (USA: AK, CA, OR)
Substrate: isolated from stream water, riparian soil

Retrieved February 01, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional info:
Disease note: abundant in stream water, but not overly pathogenic. Not associated with disease in riparian ecosystems.
Hosts: n/a

Additional references and links

 

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

 

• Google All Phytophthora riparia
• Google Images Phytophthora riparia
• Google Scholar Phytophthora riparia

Fact sheet author

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