Phytophthora flexuosa

Name and publication

Phytophthora flexuosa Jung, Horta Jung, Scanu & Bakonyi (2017) 

Jung T, Jung MH, Scanu B, Seress D, Kovács GM, Maia C, Pérez-Sierra A, Chang T-T, Chandelier A, Heungens K, van Poucke K, Abad-Campos P, Léon M, Cacciola SO, and Bakonyi J. 2017 Six new Phytophthora species from ITS Clade 7a including two sexually functional heterothallic hybrid species detected in natural ecosystems in Taiwan. Persoonia 38: 100–135.

Corresponding author:,


from Jung et al. (2017)




refers to the flexuose oogonial walls (flexuosa Lat = flexuose, bulged)


Type: TAIWAN, Taiping Mountain, isolated from rhizosphere soil of a mature Fagus hayatae tree, T. Jung, 2013 (CBS H-22550 holotype, dried culture on V8A, Herbarium CBS-KNAW Fungal Biodiversity Centre)

Ex-type: CBS 141201 = TW78

Sequences for ex-type in original manuscript: Phytophthora flexuosa isolate TW78 = ITSrDNA KU517152, cox1 KU517146

Ex-type in other collections

CBS 141201 = TW78 = 67C3 (Yang)

Molecular identification

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

Phytophthora flexuosa isolate TW78 ITS rDNA KU517152

Sequences for ex-type in other sources
  • NCBI: Phytophthora flexuosa TW78
  • Phytophthora DATABASE: Phytophthora flexuosa
  • EPPO-Q-bank: Phytophthora flexuosa
  • BOLDSYSTEMS: Phytophthora flexuosa
Position in ITS phylogenetic tree

Clade 7a

Morphological identification

adapted from Jung et al. (2017)

Colonies and cardinal temperatures

Colony morphology on V8A and MEA is uniform, and on PDA dome-shaped woolly. Minimum growth temperature 5°C, optimum 25°C, and maximum 35°C.

Conditions for growth and sporulation

Sporangia not observed on solid agar but produced abundantly in non-sterile soil extract; gametangia produced in single culture on V8A within 5 days. Hyphal swellings regularly formed in liquid culture and solid agar.

Asexual phase

Sporangia nonpapillate; persistent; ovoid, elongate, ellipsoid, obpyriform, and limoniform (34.9–74.8 μm length × 22.8–49.7 μm width); presenting internal nested and extended proliferation; borne on unbranched sporangiophores. Hyphal swellings inflated, tubular to coralloid. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia with ornamented walls and sometimes smooth-walled, globose, subglobose (25.7–42.8 μm diam.), flexuose, or elongated, often with long tapering to funnel-like and curved bases; antheridia paragynous, clavate, subglobose to cylindrical, often with finger-like hyphal projections; oospores plerotic, globose or elongated and containing a large ooplast and often two nuclei (22.7–37.7 μm diam.) and with thick walls.

Hosts and distribution

Distribution: Asia (Taiwan)
Substrate: rhizosphere soil
Host: Fagus hayatae (Fagaceae)

Retrieved January 30, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

  • Phytophthora DATABASE: Phytophthora flexuosa
  • EPPO-Q-bank: Phytophthora flexuosa
  • SMML USDA-ARS: Phytophthora flexuosa
  • EPPO Global Database: Phytophthora flexuosa
  • CABI Invasive Species Compendium: Phytophthora flexuosa
  • Encyclopedia of Life (EOL): Phytophthora flexuosa
  • Index Fungorum (IF): Phytophthora flexuosa
  • Plantwise Knowledge Bank: Phytophthora flexuosa

Fact sheet author

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