Name and publication

Phytophthora austrocedri Gresl. & E.M. Hansen (2007)

Greslebin AG, Hansen EM, and Sutton W. 2007. Phytophthora austrocedrae sp. nov., a new species associated with Austrocedrus chilensis mortality in Patagonia (Argentina). Mycol. Res. 111: 308–316.

Corresponding author: alina@ciefap.org.ar

Nomenclature

from Greslebin et al. (2007)

Mycobank

MB530225

Synonymy

≡ Phytophthora austrocedrae Gresl. & E.M. Hansen (2007) [MB#510267] (orthographic variant)

Etymology

refers to the host Austrocedrus chilensis

Typification

Type: ARGENTINA, from roots and stem of Austrocedrus chilensis (Ciprés de la Cordillera or Cordilleran Cypress) collected on Oct. 2005 by A. Greslebin in Chubut, Parque Nacional Los Alerces (CIEFAP 203, Centro de Investigacion y Extension Forestal Andino Patagonico)

Ex-type: culture ATCC MYA-4074 (AG203)

Sequences for ex-type in original manuscript: Phytophthora sp. austrocedrae isolate AG203 = ITS rDNA: DQ995184 (1194bp 18S + ITS)

Ex-type in other collections

(ET) CBS 122911, ATCC MYA-4074, AG203, CIEFAP 203, WPC P16040, Gresbelin 203, S&T BL 5 (Abad), 41B6 (Hong)

Molecular identification

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

Phytophthora austrocedri isolate CPHST BL 5 (= P16040 WPC) = ITS rDNA MG783380, COI MH136850

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 austrocedri CPHST BL 5
• NCBI: Phytophthora austrocedri AG203 (PAU-09-002)
• NCBI: Phytophthora austrocedri P16040
• EPPO-Q-bank: Phytophthora austrocedri CBS 122.911
• BOLDSYSTEMS: Phytophthora austrocedri PHYTO117-10 = P16040 (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
8d

Morphological identification

adapted from Greslebin et al. (2007)

Colonies and cardinal temperatures

Colonies in CMA, V8, and PDA are uniform with non-distinctive pattern and with slow growth. Minimum temperature is 3°C, optimum 15–21°C, and maximum 24°C.

Conditions for growth and sporulation

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
are produced in water cultures (soil extract or river water) and not observed in solid media. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are formed in single-strain culture in different media including CMA, V8-A, PDA, and HS with oil. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
were usually formed in selective media after about 20 d.

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
semipapillatesemipapillate:
pertaining to the production of shallow having papilla that are not well developed, shallow and less nipple-like than fully papillate structures
; 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)
, limoniform, or 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
frequently with distorted shapes with average size of 50 x 36 µm (22–83 µm x 15–58 µm), and produced in unbranched sporangiophores. Sporangiophores frequently have hyphal swellings. 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
with hyphal projections and lateral attachment of the sporangiophoresporangiophore:
the hyphal strand on which the sporangium is formed; may be branched or unbranched to form compound sympodia or simple sympodia
are frequently observed. Hyphal swellings are usually formed in liquid and solid media and are globoseglobose:
having a rounded form resembling that of a sphere
to subglobose, catenulated and sometimes with distorted shapes. 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
produced in approx. 20 days and are globoseglobose:
having a rounded form resembling that of a sphere
[39 µm diameter (22–56 µm)] with smooth walls; antheridiaantheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
are amphigynousamphigynous:
pertaining to the sexual stage in which the antheridium completely surrounds the stalk of the oogonium (cf. paragynous)
; and oosporesoospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
are 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)
.

Most typical characters

Phytophthora austrocedri is characterized by the production of persistentpersistent:
pertaining to sporangia that remain attached to the sporangiophore and do not separate or detach easily (cf. caducous)
sporangia, hyphal swellings readily formed in water and solid culture, and slow growth rate.

Additional specimen(s) evaluated

Phytophthora austrocedrae CPHST BL 5 (Abad) = (P16040 World Phytophthora Collection – California, USA) duplicate of the ex-type CIEFAP 203

Hosts and distribution

Distribution: Asia (Iran), Europe (England, Germany, Scotland), South America (Argentina)
Substrate: isolated from necrotic lesions of stems and roots
Disease note: dieback, mortality; associated with 'mal del cipres' disease
Host: Austrocedrus chilensis, Juniperus communis, Cupressus sempervirens (Cupressaceae)

Retrieved January 17, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional information: The natural host of P. austrocedrae in South America is the Chilean cedar (Austrocedrus chilensis). In the UK, Lawson cypress (Chamaecyparis lawsoniana), Nootka cypress (Chamaecyparis nootkatensis), and the common juniper (Juniperus communis) have been confirmed as hosts in 2011. https://www.forestresearch.gov.uk/research/phytophthora-austrocedri/

Quarantine status

USA: Phytophthora austrocedrae is listed in the “Additional Pests of Concern” by the National Cooperative Agricultural Pest Survey (CAPS) for 2017, 2018, and 2019.

​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

Forest Research UK Phytophthora austrocedrae

Forest Research: Phytophthora austrocedrae on juniper factsheet

Mackesy, D., and Sullivan, M. 2013. CPHST Pest Datasheet for Phytophthora austrocedrae USDA-APHIS-PPQ-CPHST. Revised in 2018 by L. Morales, D. Mackesy, and N. Miller.

 

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

 

 

• Google All Phytophthora austrocedrae
• Google Images Phytophthora austrocedrae
• Google Scholar Phytophthora austrocedrae

 

Fact sheet author

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