Name and publication

Phytophthora lacustris Brasier, Cacciola, Nechw., T. Jung & Bakonyi (2013)

Nechwatal J, Bakonyib J, Cacciola SO, Cooke DEL, Jung T, Nagy ZA, Vannini A, Vettraino AM, and Brasier CM. 2013. The morphology, behaviour, and molecular phylogeny of Phytophthora taxon Salixsoil and its redesignation as Phytophthora lacustris sp. nov. Plant Pathology 62: 355–369.

Corresponding author: jan.nechwatal@lfl.bayern.de

Nomenclature

from Nechwatal et al. (2013)

Mycobank

MB564262

Etymology

(Lat. = from lakes, lacustrine) refers to the wet habitats preferred by this species

Typification

Type: UNITED KINGDOM: Bexley Heath, Kent, isolated from diseased root of Salix matsudana, 1972, C. M. Brasier & R. G. Strouts, P245 (dried culture on CA, herbarium of the Plant Protection Institute, Hungarian Academy of Sciences, Budapest, under accession number PPIHAS-P566)

Ex-type: culture P245 (UK Forestry Commission Culture Collection = IMI 389725: no results found) = P10337 at WPC

Sequences for ex-type in original manuscript: P245 = ITS AF266793, COX1 JF896561

NOTE: In previous studies P. lacustris is referred to as P. taxon Salixsoil.

Ex-type in other collections

(ET) CABI IMI389725 (PA), WPC P10337, S&T BL 69 (Abad), P245 (UK Forestry Commission)

Molecular identification

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

Phytophthora lacustris isolate P245 = ITS rDNA AF266793
Phytophthora lacustris isolate CPHST BL 69 ( = P10337) COI MH136916

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 lacustris CPHST BL 69
• NCBI: Phytophthora lacustris P10337
• NCBI: Phytophthora lacustris P245
• EPPO-Q-bank: Phytophthora lacustris
• BOLDSYSTEMS: Phytophthora lacustris (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
6d

Morphological identification

adapted from Nechwatal et al. (2013)

Colonies and cardinal temperatures

Colony colony:
assemblage of hyphae which usually develops form a single source and grows in a coordinated way
grown for 7 days on V8 agar, potato dextrose agar, and malt extract agar with chrysanthemum pattern. Minimum growth temperature 3°C, maximum 28–30°C, and optimum 37°C.

Conditions for growth and sporulation

Sporangia abundantly produced in nonsterile soil filtrate.

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
or obpyriformobpyriform:
inversely pear-shaped, i.e. with the widest part at the point of attachment (cf. pyriform)
(30–55 X 22–38 µm), showing internal, nested or extended proliferationextended proliferation:
a type of internal proliferation in which the sporangiophore originates from inside of an empty sporangium, and continues to grow through and out of the old sporangium
, sometimes with 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 unbranched or with new sporangiophores emerging just below the mature sporangiumsporangium:
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
. Hyphal swellings are rarely produced, subglobose 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
(12–18 X 8–10 µm), intercalaryintercalary:
positioned within a hypha (cf. terminal)
. 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

Sterile. Sexual phase not observed, but isolates have induced gametangial formation in some A2 isolates of other species, e.g. P. cambivora (the P. lacustris isolate remained sterile, referred to as having a "silent A1 mating typemating type:
molecular mechanisms that regulate compatibility in sexual reproduction in heterothallic species (also referred to as compatibility type); typically denoted as A1 or A2
").

Most typical characters

Phytophthora lacustris is characterized by the presence of 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 nested or extended proliferationextended proliferation:
a type of internal proliferation in which the sporangiophore originates from inside of an empty sporangium, and continues to grow through and out of the old sporangium
and the production of intercalaryintercalary:
positioned within a hypha (cf. terminal)
hyphal swellings.

Additional specimen(s) evaluated

Phytophthora lacustris CPHST BL 69 ex-type = P10337 (World Phytophthora Collection)

Hosts and distribution

Notes: published online 2012; known as "Phytophthora taxon Salixsoil" before formal description

Distribution: widespread
Substrate: roots, bark; isolated from soil, water
Disease note: root rot, discoloration; weak bark pathogen
Host: Alnus spp. (Betulaceae), Salix sp. (Salicaceae), Prunus sp. (Rosaceae); associated with Phragmites australis (Poaceae).

Retrieved January 31, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

 

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

 

• Google All Phytophthora lacustris
• Google Images Phytophthora lacustris
• Google Scholar Phytophthora lacustris
• Google All Phytophthora salix soil
• Google Images Phytophthora salix soil
• Google Scholar Phytophthora salix soil

Fact sheet author

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