Name and publication

Phytophthora abietivora D.W. Li, N.P. Schultes, J. A. LaMondia, R. S. Cowles (2019)

Li DW, Schultes NP, LaMondia JA, Cowles RS. 2019. Phytophthora abietivora, a new species isolated from diseased Christmas trees in Connecticut, USA. Plant Disease 18 (103): 3057–3064.

Corresponding author: R. S. Cowles; richard.Cowles@ct.gov

Nomenclature

Mycobank

MB830083

Etymology

Latin, abies, referring to conifer genus Abies and -vora, ones that eat

Typification

Type: USA, Connecticut, Brooklyn, Allen Hill Farm (41°45.997′N 71°55.182′W), from infected root of a Christmas tree of Abies fraseri (Pursh) Poir., 10 October 2017, R.S. Cowles, UAMH 12075 (RC2017-1). Holotype specimen is a living specimen being maintained via lyophilization at UAMH Centre for Global Microfungal Biodiversity, The Gage Research Institute, Toronto, Canada.

Ex-type: culture NRRL66892

Sequences for ex-type in original manuscript:  ITS MK163944, cox1 MK164270, β-tubulin MK164274, nadh1 MK164269, hsp90 MK164275

Ex-type in other collections

(ET) NRRL 66892, RC2017-1, UAMH 12075

Molecular identification

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

Phytophthora abietivora ITS rDNA, COI

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 abietivora
• EPPO-Q-bank: Phytophthora abietivora
• BOLDSYSTEMS: Phytophthora abietivora

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
7a

Morphological identification

Colonies and cardinal temperatures

No information on morphology or cardinal temperature in manuscript.

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
 produced on 10% V8A agar plates flooded with root extract at 15°C under fluorescent light for 7 days. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are formed readily 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
were non-papillate, non-caducous and predominantly ovoidovoid:
egg-shaped, with the widest part at the base of the sporangium and the narrow part at the apex
in shape with internal nested proliferationnested proliferation:
a type of internal proliferation where a new sporangium develops successively inside the old sporangium after it has emptied
. 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
averaged 33.5 x 25.1 µm (overall range 27.1–41.8 x 17.1–30.8 µm). Sporangiophores unbranched. Hyphal swellings present. Chlamydospores present.

Sexual phase

Homothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
size ranged from 32.1–55.5 µm. 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)
to slightly 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)
, thick-walled, size ranged 26.5–42.5 µm. OosporesOospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
often aborted after formation of the walls. AntheridiaAntheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
paragynousparagynous:
pertaining to the sexual stage in which the antheridium is attached to the side of the oogonium (cf. amphigynous)
.

Most typical characters

Phytophthora abietivora produced large oosporesoospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
with thick walls which differentiate it from related species, P. flexuosa and P. europea.

Hosts and distribution

Distribution: USA; Connecticut
Substrate: roots
Disease note: root rot of young Abies fraseri
Host: Abies fraseri

Additional references and links

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

Fact sheet author

Treena Burgess, Ph.D., Phytophthora Science and Management, Harry Butler Institute, Murdoch University, Australia

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