Name and publication

Phytophthora mediterranea C. Bregant, Mulas & Linald. (2021)

Bregant C, Mulas AA, Rossetto G, Deidda A, Maddau L, Piras G, Linaldeddu BT. 2021. Phytophthora mediterranea sp. nov., a new species closely related to Phytophthora cinnamomi from nursery plants of Myrtus communis in Italy. Forests 12 (6): 682.

Corresponding author: benedetto.linaldeddu@unipd.it

Nomenclature

Mycobank

MB839612

Etymology

refers to the Mediterranean region, where the species was originally discovered

Typification

Type: ITALY, Oristano, isolated from roots of a potted plant of Myrtus communis, 18 April 2019, isolated by Antonio Mulas, HOLOTYPE CBS H-24768, a dried culture on CA

Ex-type: culture CBS 147720 = CB84

Sequences for ex-type in original manuscript:  ITS MW892398, ß-tubulin MW900443, cox1 MW900447

Selected specimen(s) in other collections

(ET) CBS 147720, NRRL 64337, S&T BL 217 (Abad), CB84

Molecular identification

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

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

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
7c

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, radiate on MEA, and cottony with no pattern on CA. Minimum growth temperature 10°C, optimum 32°C, and maximum 38°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 unsterile pond water after 36-48 h. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
not formed in single or paired cultures.

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
to ellipsoidellipsoid:
refers to a solid body that forms an ellipse in the longitudinal plane and a circle in cross section; many fungal spores are ellipsoidal or elliptic
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 43 x 30 µm (overall range 27–65 x 20–47 µm). Sporangiophores unbranched. 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, abundant.

Sexual phase

Sterile in culture.

Most typical characters

Phytophthora mediterranea is separated from related species P. cinnamomi and P. parvisora by its higher maximum and optimum temperature value for growth.

Additional specimen(s) evaluated

ITALY: Oristano, isolated from rhizosphere and fine roots of a potted plant of Myrtus communis, 12 November 2020, isolated by Carlo Bregant; culture CB85

Hosts and distribution

Distribution: Italy
Substrate: root and collar
Disease note: plants showed wilting foliage, chlorosis, stunted growth and sudden death symptoms in nurseries
Host: Myrtus communis

Additional references and links

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

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.