Name and publication

Phytophthora cathayensis C. Morales-Rodríguez, Y. Wang & A. Vannini, sp. nov. (2021)

Morales-Rodríguez C, Wang Y, Martignoni D, Vannini A. 2021. Phytophthora cathayensis sp. nov., a new species pathogenic to Chinese Hickory (Carya cathayensis) in southeast China. Fungal Systematics and Evolution 7 (1): 99–111.

Corresponding author: moralescorreo@hotmail.com

Nomenclature

Mycobank

MB834619

Etymology

name refers to Carya cathayensis, the host plant from which all isolates were obtained

Typification

Type: CHINA, Zhejiang, Hangzhou, Lina, Tuankou, isolated from small pieces of cambium and adjacent xylem tissue from Carya cathayensis tree with collar canker, 2017, C. Morales-Rodríguez; CGMCC No. 19655 (preserved as metabolically inactive culture, China General Microbial Culture Collection, CGMCC No. 19655)

Ex-type: CP30 = CGMCC No. 19655

Sequences of Ex-type in manuscript: ITS MN385741, cox1 MN692211, ß-tubulin MT063102, HSP90 MT063109

Ex-type in other collections

(ET) CGMCC 19655, CP30

Molecular identification

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

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

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
4

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 MEA, stoloniferous felty colonies on PDA, and uniform on V8A. Minimum growth temperature 7.5°C, optimum 25°C, and maximum 30°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 on soil extract after 24–36 hours in the dark. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are formed readily in single cultures on V8A after 15–20 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)
, 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. 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 27.3 x 18.6 µm (overall range 28–85 x 21–50 µm). Sporangiophores simple.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, rare.

Sexual phase

Homothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
smooth-walled, size ranged from 20–29 µm. OosporesOospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
mostly pleroticplerotic:
pertaining to an oospore that fills the oogonium (cf. aplerotic)
, size ranged 18–25 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

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
4. A single isolate from the USA recovered from pecans, informally known as P. sp. pecan has identical sequence to P. cathayensis.

Additional specimen(s) evaluated

CHINA, Zhejiang, Hangzhou, Lina, Tuankou, isolated from small pieces of cambium and adjacent xylem tissue from Carya cathayensis tree with collar canker, 2017, C. Morales-Rodríguez, CP29; CP31

Hosts and distribution

Distribution: China
Substrate: tree collar
Disease note: trunk lesions of Carya cathayensis leading to a severe decline and dieback
Host: Carya cathayensis

Additional references and links

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

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.