Name and publication

Phytophthora ×vanyenensis Q.N. Dang and T. I. Burgess (2021)

Dang QN, Pham TQ, Arentz F, Hardy GE, Burgess TI. 2021. New Phytophthora species in cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
2a from the Asia-Pacific region including a re-examination of P. colocasiae and P. meadii. Mycological Progress 20 (2): 111–129.

Nomenclature

Mycobank

MB836443

Etymology

referring to the locality (Van Yen) where this species was recovered

Typification

Type: VIETNAM, Yen Bai, Van Yen, water from Cinnamomum cassia plantation, Sep. 2018, Q.N. Dang, Holotype MURU488

Ex-type: culture CBS 146554

Sequences of ex-type in manuscript:  ITS MT568651, β-tubulin MT583634, hsp90 MT583680, cox1 MT583648, cox2 MT583665, nadh1 MT583695, rps10 MT583709

Ex-type in other collections

(ET) CBS 146554, QD13; VTN2B

Molecular identification

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

Phytophthora × vanyenensis 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 × vanyenensis
• EPPO-Q-bank: Phytophthora × vanyenensis
• BOLDSYSTEMS: Phytophthora × vanyenensis

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
2a

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 cottony and stellate on CA, dense and stellate on PDA, smooth and thin on MEA, and submerged and stellate on V8A. Minimum growth temperature 4°C, optimum 30°C, and maximum 32.5°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
are produced in water cultures (soil extract) and not observed in solid media. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are formed readily in paired cultures on V8A after about 21 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
were semi-papillate to papillatepapillate:
pertaining to the production of a distinct papilla at the distal end of the sporangium (cf. nonpapillate and semipapillate)
often bipapillate, mostly persistentpersistent:
pertaining to sporangia that remain attached to the sporangiophore and do not separate or detach easily (cf. caducous)
, and variable in shape 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)
. 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 52.8 x 33.5 µm (overall range 36.4–74.3 x 19.6–51.7 µm). Sporangiophores simple. Hyphal swellings rare. 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

Heterothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
had smooth walls, and size ranged from 20–26.9 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 semi-aplerotic, globoseglobose:
having a rounded form resembling that of a sphere
, size ranged 17.1–24.8 µm. Copious oosporesoospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
produced but about 60% aborted after the formation the wall. 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)
amphigynousamphigynous:
pertaining to the sexual stage in which the antheridium completely surrounds the stalk of the oogonium (cf. paragynous)
often with digitate projections.

Most typical characters

Phytophthora × vanyenensis resides in cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
2a, and P. mekongensis is one of the parent species; the other is unknown.

Additional specimen(s) evaluated

Viet Nam, Yen Bai, Van Yen, rhizosphere soil from Cinnamomum cassia plantations, 2018, Q.N. Dang, QD12; water from Cinnamomum cassia plantations QD30; QD32

Hosts and distribution

Distribution: Vietnam
Substrate: roots
Disease note: root rot of Cinnamomum cassia, in conjunction with P. cinnamomi
Host: Cinnamomum cassia

Additional references and links

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

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.