Name and publication

Phytophthora agathidicida B.S. Weir, Beever, Pennycook & Bellgard (2015)

Weir BS, Paredes EP, Anand N, Uchida JY, Shaun R, Pennycook SEB, and Beever RE. 2015. A taxonomic revision of Phytophthora Clade clade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
5 including two new species, Phytophthora agathidicida and P. cocois. Phytotaxa 205: 21–38 (pg. 29).

Corresponding author: WeirB@LandcareResearch.co.nz

Nomenclature

from Weir et al. (2015)

Mycobank

MB550518

Index Fungorum

IF550518

Etymology

Latin noun: agathid- (linguistic stem of Agathis) and -cida (suffix: one who kills)—the Agathis killer

Typification

Type: NEW ZEALAND. Coromandel: Great Barrier Island, from bleeding lesion on trunk of Agathis australis (D. Don) Lindl. ex Loudon, 23 Mar. 2006, R.E. Beever REB316-14, dried culture specimen PDD 91595. [PDD = New Zealand Fungal and Plant Disease Fungarium (New Zealand)].

Ex-type: living culture preserved in a metabolically inactive state as ICMP 17027 International Collection of Micro-organisms from Plants and P15175 (WPC - World Phytophthora Collection)

Sequences for ex-type in original manuscript: ICMP 17027 = ITS KP295308, COX1 KP295222, YPT1 KP295429, HSP90 KP295276, L10 KP295363, ENL KP295255, ND1 KP295334, TIGA KP295392

Ex-type in other collections

(ET) CBS 149819, NRRL 64473, ICMP 17027, WPC P15175, NZFS 3770, S&T BL 154 (Abad), 67D5 (Hong)

Molecular identification

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

Phytophthora agathicida isolate CPHST BL 154 (= P15175 WPC) = ITS rDNA MG602692, COI MK493471

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 agathidicida CPHST BL 154
• NCBI: Phytophthora agathidicida ICMP 17027
• NCBI: Phytophthora agathidicida P15175 submitted to NCBI as P. katsurae or P. cf katsurae
• EPPO-Q-bank: Phytophthora agathidicida
• BOLDSYSTEMS: Phytophthora agathidicida

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
5

Genome sequence

Phytophthora agathidicida strain ex-type NZFS 3770. Accession genome NZFS 3770 v2, BioProject PRJNA290659, University of Exeter (2015), Studholme et al. 2015

Morphological identification

adapted from Weir et al. (2015)

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 in V8-A, PDA, and MEA is non-distinctive pattern. Minimum growth temperature 6°C, maximum 25°C, and optimum 21.5°C.

Conditions for growth and sporulation

Oogonia quickly produced (3–4 days) and abundant on V8A.

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
papillatepapillate:
pertaining to the production of a distinct papilla at the distal end of the sporangium (cf. nonpapillate and semipapillate)
, persistentpersistent:
pertaining to sporangia that remain attached to the sporangiophore and do not separate or detach easily (cf. caducous)
, globoseglobose:
having a rounded form resembling that of a sphere
to ovoid- 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
 (12–50 μm width, and 15–75 μm length), borne terminally from irregular branched or unbranched sporangiophores and could be formed via internal proliferationinternal proliferation:
internal proliferation occurs when the sporangiophore continues to grow through an empty sporangium
. Hyphal swellings simple with slight swellings. 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

Homothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
globoseglobose:
having a rounded form resembling that of a sphere
(32 μm diam) with wall ornamentation mildly stipulate (small protuberances). 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)
, globoseglobose:
having a rounded form resembling that of a sphere
, some with knots at the base. 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)
, nearly filling the oogoniaoogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
, with a mean diameter 28 μm.

Observations in specimen P. agathidicida CPHST BL 154 in hemp seed agar + oil: Oogonia globose (32–40 μm diam), with wavy wall ornamentation, and mostly with tapered bases (same character observed in photos of original publication of Weir et al. 2015). Antheridia amphigynous, sometimes with digitate projections. OosporesOospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
 thick-walled and pleroticplerotic:
pertaining to an oospore that fills the oogonium (cf. aplerotic)
 (28–36 μm diam). 

Most typical characters

Phytophthora agathidicida differs from other Phytophthora clade 5 species in its oogoniumoogonium:
the female gametangium in which the oospore forms after fertilization by the antheridium
ornamentation with occasional and slightly raised protuberances, and its larger mean oosporeoospore:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
diameter (28 μm).

Additional specimen(s) evaluated

Phytophthora agathidicida CPHST-BL 154 (Abad) = ex-type P15175 [World Phytophthora Collection (WPC) California, USA]

Hosts and distribution

Distribution: northern New Zealand
Substrate: tree trunks
Disease note: canopy thinning - little leaf syndrome, collar-rot of lower trunk, girdling, bleeding lesions
Host: kauri (Agathis australis) trees and associated soil

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

Additional references and links

 

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

 

 

• Google All Phytophthora agathidicida
• Google Images Phytophthora agathidicida
• Google Scholar Phytophthora agathidicida
• Google All Phytophthora taxon agathis
• Google Images Phytophthora taxon agathis
• Google Scholar Phytophthora taxon agathis 

 

Fact sheet author

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