Phytophthora agathidicida

Name and publication

Phytophthora agathidicida 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 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

ICMP 17027 = NZFS 3770, P15175 (WPC), CPHST BL 154 (Abad), 67D5 (Yang)

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

Sequences for ex-type with other genes and in other sources
Position in ITS phylogenetic tree

Clade 5

Genome sequence of ex-type

Phytophthora agathidicida strain: NZFS 3770

Morphological identification

adapted from Weir et al. (2015)

Colonies and cardinal temperatures

Colony 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

Sporangia papillate, persistent, globose to ovoid-ellipsoid (12–50 μm width, and 15–75 μm length), borne terminally from irregular branched or unbranched sporangiophores and could be formed via internal proliferation. Hyphal swellings simple with slight swellings. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia globose (32 μm diam) with wall ornamentation mildly stipulate (small protuberances). Antheridia amphigynous, globose, some with knots at the base. Oospores plerotic, nearly filling the oogonia, 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. Oospores thick-walled and plerotic (28–36 μm diam). 

Most typical characters

Phytophthora agathidicida differs from other Phytophthora clade 5 species in its oogonium ornamentation with occasional and slightly raised protuberances, and its larger mean oospore 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

  • Phytophthora DATABASE: Phytophthora agathidicida
  • EPPO-Q-bank: Phytophthora agathidicida
  • SMML USDA-ARS: Phytophthora agathidicida
  • EPPO Global Database: Phytophthora agathicida
  • Forest Phytophthoras of the World: Phytophthora agathidicida
  • CABI Invasive Species Compendium: Phytophthora agathidicida
  • Encyclopedia of Life (EOL): Phytophthora agathidicida
  • Index Fungorum (IF): Phytophthora agathidicida
  • Plantwise Knowledge Bank: Phytophthora agathidicida

Fact sheet author

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Beltsville Laboratory, United States of America