Name and publication

Phytophthora irrigata C.X. Hong & Gallegly (2008)

Hong C, Gallegly ME, Richardson PA, Kong P, and Moorman GW. 2008. Phytophthora irrigata, a new species isolated from irrigation reservoirs and rivers in eastern United States of America. FEMS Microbiol Lett 285: 203–211.

Corresponding author: C. Hong chhong2@vt.edu

Nomenclature

from Hong et al. (2008)

Mycobank

MB538246

Etymology

refers to the habitat (‘irrigation’ water) where it was isolated

Typification

Type: UNITED STATES OF AMERICA, isolated from water of irrigation reservoir in Virginia during the year 2000 by Hong (23J7) MYA-4457

Ex-type: MYA-4457

Sequences for ex-type in original manuscript: Phytophthora sp. 23J7 = ITS rDNA EU334634, β-tub EU595775, TEF EU595778, CoxII EU595783, NADH EU595786

Ex-type in other collections

(ET) NRRL 64264, MYA-4457, P108 (WVU), WPC P16861, S&T BL 41 (Abad), 23J7 (Hong), p108 (Gallegly)

Molecular identification

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

Phytophthora irrigata isolate CPHST BL 41 (= P16861 WPC) = ITS rDNA MG865520, COI MH136914

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 irrigata CPHST BL 41
• NCBI: Phytophthora irrigata P16861
• NCBI: Phytophthora irrigata 23J7
• EPPO-Q-bank: Phytophthora irrigata 
• BOLDSYSTEMS: Phytophthora irrigata (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. (2008)

Colonies and cardinal temperatures

Colony colony:
assemblage of hyphae which usually develops form a single source and grows in a coordinated way
morphology after 7 days of growth on potato dextrose agar and malt extract with petaloid pattern and on V8 agar with light petaloid pattern. Minimum temperature for growth is 7°C, optimum 30°C, and maximum 40°C.

Conditions for growth and sporulation

Sporangia formed in 10% soil solution. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
and oosporesoospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
show golden brown color in hemp seed agar.

Asexual phase

Sporangia nonpapillate; 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
, globoseglobose:
having a rounded form resembling that of a sphere
, and obpyriformobpyriform:
inversely pear-shaped, i.e. with the widest part at the point of attachment (cf. pyriform)
(34–51 L x 27–42 W µm); with internal extended and nested proliferationnested proliferation:
a type of internal proliferation where a new sporangium develops successively inside the old sporangium after it has emptied
; and originated mostly on long unbranched sporangiophores. Hyphae 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

Heterothallicheterothallic:
pertaining to sexual reproduction in which conjugation is possible only through interaction of different thalli (i.e. different mating types) (cf. homothallic)
. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
(31–51µm diam); antheridiaantheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
amphigynousamphigynous:
pertaining to the sexual stage in which the antheridium completely surrounds the stalk of the oogonium (cf. paragynous)
(16 x 10.2 µm); oospores plerotic plerotic:
pertaining to an oospore that fills the oogonium (cf. aplerotic)
and 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)
(40 µm diam), walls about 3 µm thick.

Most typical characters

Additional specimen(s) evaluated

Phytophthora irrigata, ex-type CPHST BL 41, duplicate of P16861 (World Phytophthora Collection), which is a duplicate of ex-type MYA-4457

Hosts and distribution

Notes: The nature of the type is uncertain.
Distribution: North America (USA)
Substrate: isolated from water

Retrieved January 31, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional info:
Host: Rhododendron spp. 
Substrate: irrigation water

Additional references and links

 

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

 

• Google All Phytophthora irrigata
• Google Images Phytophthora irrigata
• Google Scholar Phytophthora irrigata

Fact sheet author

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