Phytophthora stricta

Name and publication

Phytophthora stricta Yang, Copes & Hong (2014)

Yang X, Copes WE, and Hong C. 2014. Two novel species representing a new clade and cluster of Phytophthora. Fungal Biology 118: 72–82.

Corresponding author: Xiao Yang


from Yang et al. (2014)




‘Stricta' refers to the constrictions of sporangiophores.


Type: UNITED STATES OF AMERICA, recovered from the surface water in a nursery reservoir, Mississippi, February, 2012; holotype ATCC MYA-4944

Ex-type 58A1

Sequences for ex-type in original manuscript: 58A1 = ITS rDNA KF192694, Cox 1 (Kroon et al 2004) KF192702

Ex-type in other collections

58A1 = ATCC MYA-4944 = P19972 (WPC), CPHST BL 127 (Abad), 58A1 (Yang)

Molecular identification

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

Phytophthora stricta isolate CPHST BL 127 (= P19972 WPC) = ITS rDNA MG865589, COI MH136981

Sequences for ex-type in other sources
Position in ITS phylogenetic tree

Clade X

Morphological identification

adapted from Yang et al. (2014)

Colonies and cardinal temperatures

Colony morphology on PDA, V8A, MEA with no distinct pattern. Minimum growth temperature 9°C, optimum 25–30°C, and maximum 33°C.

Conditions for growth and sporulation

Sporangia produced overnight in 1.5 % soil water extract solution. Most isolates are A1, and gametangia are produced in dual cultures with Phytophthora cinnamomi (A2) and Phytophthora meadii (A2).

Asexual phase

Sporangia nonpapillate, sometimes caducous with short and long pedicels; ovoid, limoniform, obpyriform, ellipsoid, pyriform, and obovoid (av. 62 L x 35 W µm) with internal and nested proliferation, sometimes with external proliferation; originated in unbranched sporangiophores; sometimes with one to three constrictions in areas were the pedicel gets broken. Hyphal swellings absent. Chlamydospores terminal, spherical (av. 35 µm diam) or peanut-shaped.

Sexual phase

Heterothallic. Oogonia smooth-walled, turning gold at maturation, globose (av. 29 µm diam); antheridia amphigynous, often cylindrical (av.19 L x 15 W µm); oospores plerotic (av. 25 µm diam), sometimes with two ooplasts or aborted.

Most typical characters

Phytophthora stricta can be distinguished by the shape of the big cylindrical antheridia.

Additional specimen(s) evaluated

Phytophthora stricta ex-type CPHST BL 127, duplicate of P19972 (World Phytophthora Collection), which is a duplicate of ATCC MYA-4944

Hosts and distribution

Distribution: North America (USA: CT, MS, VA)
Substrate: isolated from water

Retrieved February 01, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

Fact sheet author

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