Phytophthora erythroseptica (to be redescribed 2022)

Name and publication

Phytophthora erythroseptica Pethybr. (1913)

Pethybridge GH. 1913. On the rotting of potato tubers by a new species of Phytophthora having a method of sexual reproduction hitherto undescribed. Scientific Proceedings of the Royal Dublin Society 13: 529–565 (pgs. 547-548).

Nomenclature

Mycobank

MB231826

Typification

from Pethybridge (1913)

Type: IRELAND, causing tuber-rot of potato, first observed in 1909 at Cliffden Co, Galway. Studies of the pathogen were conducted in 1912 and the name Phytophthora erythroseptica was proposed, and for the disease the name "pink rot" was suggested.

NOTES: IMI 34684,VKM F-1807 G.H. Pethybridge (LOST).
The following isolates cited as ex-type correspond to Phytophthora cryptogea: CBS 129.23 (referred as the type strain), P1693 (WPC), P3916 (WPC), P3453 (WPC); ATCC 58104, H14.1 (Hong), 61J2 (Yang)

Well-authenticated specimen(s) selected by Gloria Abad: 

selected specimen #1: CPHST BL 80 = P6180 (WPC) from IRELAND, isolated from potato (Solanum tuberosum), collected in Banon, Dublin in 1989

selected specimen #2: CPHST BL 36G = P0340 (WPC) from TASMANIA, isolated from potato (Solanum tuberosum)

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of selected specimens (see Molecular protocols page)

Phytophthora erythroseptica isolate CPHST BL 80 (= P6180 WPC) = ITS rDNA MG865486, COI MH136882

Phytophthora erythroseptica isolate CPHST BL 36G (= P0340 WPC) = ITS rDNA MG865487, COI MH136883

Sequences for ex-epitype in other sources

Note: NCBI: Phytophthora erythroseptica 61J2 sequences cited as ex-type are incorrect. They align with Phytophthora cryptogea (see above).

Position in ITS phylogenetic tree

Clade 8a

Morphological identification

Colonies and cardinal temperatures

Colony morphology after 7 days on V8-A with no distinct pattern; on PDA and MEA with slight chrysanthemum pattern. Minimum growth temperature 6°C, optimum 21°C, and maximum 30°C.

Asexual phase

Sporangia nonpapillated; persistent; ellipsoid, obpyriform, ovoid (23–87 x 14–36 μm), with rounded and tapered bases, ellipsoid frequently constricted in the middle; internal, external and nested proliferation is observed. Sporangia produced in unbranched or simple sympodial sporangiophores. Hyphal swellings are common. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia with smooth wall, spherical (24–42 μm diam.); antheridia predominantly amphigynous (10–18 x 12–16 μm), some with spine or digitate projections and aplerotic oospores (20–31 μm diam.).

Most typical characters

Phytophthora erythroseptica is characterized by the presence of sporangia often with a constriction distal to the middle and some amphigynous antheridia with spine or digitate projections.

Specimen(s) evaluated

Phytophthora erythroseptica CPHST BL 80, duplicate of P6180 (World Phytophthora Collection)

Phytophthora erythroseptica CPHST BL 36G, duplicate of P0340 (World Phytophthora Collection)

Hosts and distribution

Distribution: cosmopolitan
Substrate: roots, seeds, leaves, petioles, tubers
Disease note: Pink rot of potato tubers is a serious pathogen of Solanaceae and other crops. Commonly a root rot, also damping-off, seedling rot, wilt crown rot, leaf and petiole blight.
Hosts: principal hosts: Solanaceae; also on 15 other genera in 10 other families

Retrieved January 29, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

The French Industry. Leak and Pink Rot (Pythium and Phytophthora erythroseptica). Le Plant de Pomme de Terre - Francais.

Fact sheet author

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Beltsville Laboratory, United States of America