Name and publication

Phytophthora kelmanii Abad, J.A. Abad, T.I. Burgess & Mostowf. (2021)

Mostowfizadeh Ghalamfarsa R, Burgess TI, Abad ZG, Abad JA. 2021. Phytophthora kelmanii Fungal Planet 1267. In: Crous PW et al. Fungal Planet Description Sheets 1182–1283. Persoonia 46: 313–528.

Nomenclature

Mycobank

MB838760

Etymology

Named to honour Dr Arthur Kelman, Emeritus Professor at the Department of Plant Pathology, North Carolina State University, USA, and mentor of Jorge and Gloria Abad during their time at NCSU. Arthur Kelman (11 Dec. 1918 – 29 June 2009) was one of the most influential plant pathologists of the twentieth century. He was a member of the National Academy of Sciences for his pioneering contributions to the study of phytobacteriology and received numerous awards including Fellow of the International Society of Plant Pathology, American Phytopathological Society, the American Association for the Advancement of Science, and the American Academy of Microbiology.

Typification

Type: Australia, Western Australia, Armadale, baited from rhizosphere soil of Ptilotus pyramidatus, collected by Giles Hardy 2016; holotype MURU485

Ex-type: CBS 146551

Sequences of ex-type in manuscript: ITS MT210487, ß-tubulin MT210491, HSP90 MT210495, cox1 MT210499, nadh1 MT210503 and LSU MT210486

Ex-type in other collections

(ET) CBS 146551, Phyt7

Molecular identification

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

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

Position in multigenic phylogeny with 7 genes (ITS, β-tub, COI, EF1α, HSP90, L10, and YPT1)

Clade 8a

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 on V8A, CA, and MEA was uniform, rosaceous pattern on PDA. Minimum growth temperature 4°C, optimum 25°C, and maximum 37.5°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
formed readily in paired cultures on CA and V8 after about 14 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 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 with internal proliferationinternal proliferation:
internal proliferation occurs when the sporangiophore continues to grow through an empty sporangium
, both 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 46 x 31 µm (overall range 26–75 x 21–49 µm); Sporangiophores simple or loose sympodiasympodia:
a type of sporangiophore which appears simple, but where each successive sporangium develops on a branch behind and to one side of the previous apex, where growth has already ceased
. Hyphal swellings present, numerous, globoseglobose:
having a rounded form resembling that of a sphere
. 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
present.

Sexual phase

Heterothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
had wavy walls and size ranged from 27–44 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)
, globoseglobose:
having a rounded form resembling that of a sphere
and golden brown on maturity, size ranged 24–40 µm. 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)
.

Most typical characters

Phytophthora kelmanii is closely related to P. pseudocryptogea and has frequently been classified as P. cryptogea. Morphologically it is very similar to other species in cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
8a, but is distinguished by masses of globoseglobose:
having a rounded form resembling that of a sphere
hyphal swellings.

Additional specimen(s) evaluated

Australia, Western Australia, Armadale, baited from rhizosphere soil of Ptilotus pyramidatus, G Hardy, 2016, CBS 146551; baited from rhizosphere soil of Xanthorrhea pressii, 2014, VHS30761; rhizosphere soil of Salvia rosmarinus, 2018, VHS38521; USA, California, 1992, SUC629; rhizosphere soil of Juglans nigra, 1995, SCRP209

Hosts and distribution

Distribution: cosmopolitan
Substrate: roots
Disease note: Phytophthora root rot
Host: broad, including Abies spp., Picea spp., native ecosystems, numerous ornamentals, tree crops

Additional references and links

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

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.