Name and publication

Phytophthora captiosa M.A. Dick & K. Dobbie (2006)

Dick MA, Dobbie K, Cooke DEL, and Brasier CM. 2006. Phytophthora captiosa sp. nov. and P. fallax sp. nov. causing crown dieback of Eucalyptus in New Zealand. Mycol. Res. 110: 393–404.

Corresponding author e-mail: margaret.dick@ensisjv.co.nz

Nomenclature

from Dick et al. (2006)

Mycobank

MB356996

Etymology

‘captiosa’ = deceitful, referring to the deceitful nature of this pathogen and the disease it causes

Typification

Type: NEW ZEALAND, Bay of Plenty, Rotoehu Forest, from leaves of Eucalyptus salignae, 7 August 1992, C. Barr, NZFRI-M 5215 (New Zealand Forest Research Institute Herbarium – Mycology dry sample from C24242 = NZFS 310C)

Ex-type: NZFS 310C deposited at the New Zealand Forest Research Institute Culture Collection, Rotorua; also deposited at the International Collection of Micro-organisms from Plants, Auckland (ICMP 15576) and the World Phytophthora Collection, California (P10719)

Sequences for ex-type in original manuscript: Phytophthora captiosa NZFS 310C ITSrDNA DQ297402

Ex-type in other collections

(ET) CBS 119107, NZFS 310C, ICMP 15576, WPC P10719, C24242, S&T BL 11 (Abad), 46H7 (Hong)

Molecular identification

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

Phytophthora captiosa isolate CPHST BL 11 (= P10719 WPC) = ITS rDNA MG865469, COI MH136865

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 captiosa CPHST BL 11
• NCBI: Phytophthora captiosa P10719
• EPPO-Q-bank: Phytophthora captiosa CBS 119107
• BOLDSYSTEMS: Phytophthora captiosa PHYTO072-10 = P10719 (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
9d

Morphological identification

adapted from Dick et al. (2006)

Colonies and cardinal temperatures

Colonies on CA with stellate to rosaceous pattern. Minimal growth was seen at 2°C, optimum ca 25°C, and maximum 30°C.

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
, 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
(30–41 x 20–30 µm), showing both internal and external proliferationexternal proliferation:
formation of a sporangium after a sporangiophore has emerged from beneath and external to an empty sporangium that has previously emitted its zoospores (cf. internal proliferation)
, originated in unbrached sporangiophores. No hyphal swellings or 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
observed.

Sexual phase

Homothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
spherical, smooth-walled (30–43 µm diam), often exhibiting a tapered basetapered base:
pertaining to the base of a sporangium or oogonium; funnel-shaped
; 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)
, cylindrical to conical often with coiled hyphaehyphae:
single, tubular filament of a fungal or oomycete thallus; the basic structural unit of a fungus or oomycete
at the base, occasionally two-celled (17–23 x 12–17 µm); oosporesoospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
predominantly pleroticplerotic:
pertaining to an oospore that fills the oogonium (cf. aplerotic)
with thick wall up to 3 µm.

Most typical characters

Phytophthora captiosa is homothallichomothallic:
pertaining to sexual reproduction that can take place within a single thallus (i.e. self-fertile, non-outcrossing) (cf. heterothallic).
with amphigynousamphigynous:
pertaining to the sexual stage in which the antheridium completely surrounds the stalk of the oogonium (cf. paragynous)
conical antheridiaantheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
and nonpapillatenonpapillate:
pertaining to the production of a non-distinct, or inconspicuous, papilla at the distal end of the sporangium (cf. papillate and semipapillate)
sporangia. 

Additional specimen(s) evaluated

Phytophthora captiosa ex-type CPHST BL 11 duplicate of P10719 (World Phytophthora Collection)

Hosts and distribution

Distribution: New Zealand
Substrate: living leaves; also twigs, petioles, seed capsules, and peduncles
Disease note: associated with crown disease; causes premature leaf drop and twig dieback upon inoculation
Hosts: Eucalyptus botryoides, Eucalyptus saligna (Myrtaceae)

Retrieved January 29, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional information:

P. captiosa causes a crown disease of Eucalyptus botryoides and E. saligna. Symptoms include leaf spots, petiole infection, and twig and small branch lesions.

Quarantine status

USA: This species was listed as a species of concern during the 2009 Phytophthora prioritization project conducted by USDA APHIS PPQ CPHST PERAL (Schwartzburg et al.).

Additional references and links

 

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

 

• Google All Phytophthora captiosa
• Google Images Phytophthora captiosa
• Google Scholar Phytophthora captiosa

Fact sheet author

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