Name and publication

Phytophthora tonkinensis T. Jung, N.M. Chi, Scanu & I. Milenković (2022)

Jung T, Milenković I, Corcobado T. et al. 2022. Extensive morphological and behavioural diversity among fourteen new and seven described species in Phytophthora Cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
10 and its evolutionary implications. Persoonia-Molecular Phylogeny and Evolution of Fungi 49: 1–57.

Corresponding authors: thomas.jung@mendelu.cz and dr.t.jung@gmail.com

Nomenclature

Mycobank

MB 843135

Etymology

Name refers to the origin of all known isolates in northern Vietnam (Tonkin is a previous name for the three northernmost regions of Vietnam).

Typification

Type: Vietnam, Sapa, isolated from a fallen leaf in a stream running through an evergreen cloud forest, 2017, T. Jung & N.M. Chi, holotype HNHM-MYC-009701, dried culture on V8A, Herbarium of the Hungarian Natural History Museum, Budapest, Hungary

Ex-type: CBS 148852 = NRRL 64356 = VN859

Sequences for ex-type in original manuscript:  LSU ON000705, ITS ON000799, β-tubulin OM975978, hsp90 OM976495, tigA OM974672, rpl10 OM97532, tef-1a OM984958, enolase OM976589, cox1 ON013865, ypt1 ON025015, nadh1 OM976974, rps10 OM976733

Ex-type in other collections

(ET) CBS 148852, NRRL 64356, VN859 

Molecular identification

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

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

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
10b

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 uniform on V8A and with faintly striate and dendroid sectors on CA; minimal growth on PDA. Optimum growth temperature 20°C and maximum 22.5°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 in non-sterile soil extract after 2–4d. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
produced readily in single culture on V8A after 2–3 weeks.

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 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)
, and predominantly ovoidovoid:
egg-shaped, with the widest part at the base of the sporangium and the narrow part at the apex
to broad ovoidovoid:
egg-shaped, with the widest part at the base of the sporangium and the narrow part at the apex
and subglobose in shape. 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 59.2 x 37.1 µm (overall range 35.5–72.4 x 28.3–50.8 µm), 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)
internal, nested, and extended. Sporangiophores unbranched. HyphaeHyphae:
single, tubular filament of a fungal or oomycete thallus; the basic structural unit of a fungus or oomycete
irregular and coralloid with dense aggregations; hyphal swellings absent. 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
smooth to wavy walls, golden brown with age, 30–59 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)
, thin-walled, size ranged 28–57 µm. 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

Resides in phylogenetic cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
10b, most typical character is the coralloid hyphaehyphae:
single, tubular filament of a fungal or oomycete thallus; the basic structural unit of a fungus or oomycete
and low maximum temperature.

Additional specimen(s) evaluated

Vietnam, Sapa, isolated from a fallen leaf in a stream running through an evergreen cloud forest, 2017, T. Jung & N.M. Chi, VN1106, VN1107, VN1108, VN1109

Hosts and distribution

Distribution: Vietnam
Substrate: fallen leaf in stream
Disease note: no known disease
Host: no known host

Additional references and links

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

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.