Name and publication

Phytophthora variabilis T. Jung, M. Horta Jung & I. Milenković (2022)

Chen Q, Bakhshi M, Balci Y, Broders KD, Cheewangkoon R, Chen SF, Fan XL, Gramaje D, Halleen F, Horta Jung M, Jiang N, Jung T, Májek T, Marincowitz S, Milenković I, Mostert L, Nakashima C, Nurul Faziha I, Pan M, Raza M, Scanu B, Spies CFJ, Suhaizan L, Suzuki H, Tian CM, Tomšovský M, Úrbez-Torres JR, Wang W, Wingfield BD, Wingfield MJ, Yang Q, Yang X, Zare R, Zhao P, Groenewald JZ, Cai L, Crous PW. 2022. Genera of phytopathogenic fungi: GOPHY 4. Studies in Mycology 101: 417–564.

Corresponding authors: L. Cai, cail@im.ac.cn; P.W. Crous, p.crous@wi.knaw.nl

Nomenclature

Mycobank

MB 840174

Etymology

refers to the variable shapes of the oogoniaoogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
with both amphigynousamphigynous:
pertaining to the sexual stage in which the antheridium completely surrounds the stalk of the oogonium (cf. paragynous)
and paragynousparagynous:
pertaining to the sexual stage in which the antheridium is attached to the side of the oogonium (cf. amphigynous)
antheridia

Typification

Type: SLOVAKIA, Bratislava, Marianka, isolated from a commercial tree planting substrate, Jun. 2013, T. Jung (holotype CBS H-24772, dried culture on V8A

Ex-type: culture CBS 147923 = TJ915

Sequences for ex-type in original manuscript:  ITS MZ753930, cox1 MZ736447, β-tubulin MZ736472, tigA MZ7364501

Ex-type in other collections

(ET) CBS 147923, NRRL 64113, TJ915 (jung)

Molecular identification

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

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

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
7b

Morphological identification

Colonies and cardinal temperatures

Colony colony:
assemblage of hyphae which usually develops form a single source and grows in a coordinated way
morphology radiate on V8A, uniform on CA, and uniform and cottony on PDA. Minimum growth temperature <10°C, optimum 27.5°C, and maximum 5°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
produced on non-sterile soil extract. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are formed readily in single culture.

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, persistentpersistent:
pertaining to sporangia that remain attached to the sporangiophore and do not separate or detach easily (cf. 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. Proliferationproliferation:
formation of a sporangium within an empty sporangium that has previously emitted zoospores (internal or nested) or after the sporangiophore has emerged from the empty sporangium (external)
both external and internal nested and extended. 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 61 x 37.7 µm (overall range 47.2–82.5 x 25.3–48 µm). Sporangiophores unbranched. Hyphal swellings absent. ChlamydosporesChlamydospores:
an asexual spore with a thickened inner wall&nbsp;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
smooth-walled, variable shapes, size ranged from 24–50 µm. OosporesOospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
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)
, turning brown after 4 weeks. 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)
and paragynousparagynous:
pertaining to the sexual stage in which the antheridium is attached to the side of the oogonium (cf. amphigynous)
.

Most typical characters

Most distinguishing feature is the variable shape of oogoniaoogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
.

Additional specimen(s) evaluated

SLOVAKIA, Bratislava, Marianka, isolated from a commercial tree planting substrate, Jun. 2013, T. Jung; CBS 147924 = TJ1495; TJ1496; TJ1497; TJ1498

Hosts and distribution

Distribution: Slovakia
Substrate: potting mix
Disease note: none known
Host: none known

Additional references and links

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

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.