Name and publication

Phytophthora alpina Bregant, Montecchio & Linald. (2020)

Bregant C, Sanna GP, Bottos A, Maddau L, Montecchio L, Linaldeddu BT. 2020. Diversity and pathogenicity of Phytophthora species associated with declining alder trees in Italy and description of Phytophthora alpina sp. nov. Forests 11 (8): 848.

Corresponding author: benedetto.linaldeddu@unipd.it

Nomenclature

Mycobank

MB836109

Etymology

refers to the alpine environment where the species was originally found

Typification

Type: ITALY: Vigo di Cadore, isolated from rhizosphere of a declining green alder tree, 14 October 2019, collected by Carlo Bregant, holotype CBS H-24392, a dried culture on CA

Ex-type: culture OV3 = CBS 146801

Sequences for ex-type in original manuscript:  ITS MT707332, cox1 MT729668, β-tubulin MT729673

Ex-type in other collections

(ET) CBS 146801, NRRL 64334, OV3,  S&T BL 205 (Abad)

Molecular identification

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

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

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
1a

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 stellate on PDA and MEA, uniform on CA. Minimum growth temperature 2°C, optimum 20°C, and maximum 35°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 pond water after 24–36 hours. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are formed in single culture on CA after 10–20 days.

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 papillatepapillate:
pertaining to the production of a distinct papilla at the distal end of the sporangium (cf. nonpapillate and semipapillate)
, caducouscaducous:
pertaining to sporangia that become dislodged readily (i.e. deciduous) and separate from the sporangiophore (cf. persistent)
and predominantly globoseglobose:
having a rounded form resembling that of a sphere
to ovoidovoid:
egg-shaped, with the widest part at the base of the sporangium and the narrow part at the apex
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 33 x 27 µm (overall range 18 – 54 x 14 – 39 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. 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
smooth-walled, average 31 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)
, averaged 26 µm. AntheridiaAntheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
both paragynousparagynous:
pertaining to the sexual stage in which the antheridium is attached to the side of the oogonium (cf. amphigynous)
and amphigynous

Most typical characters

Morphologically similar to other species in Cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
1a especially P. cactorum.

Additional specimen(s) evaluated

ITALY: Vigo di Cadore, isolated from a bleeding canker on green alder, 26 May 2020, collected by Carlo Bregant, culture OV23

Hosts and distribution

Distribution: Italy
Substrate: roots and trunk
Disease note: bleeding cankers and rhizosphere of declining green alder trees in Italy
Host: Alnus viridis

Additional references and links

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

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.