Phytophthora nagaii

Name and publication

Phytophthora nagaii Rahman, Uematsu, Takeuchi, Shirai & Kageyama (2014)

Rahman MZ, Uematsu S, Takeuchi T, Shirai K, Ishiguro Y, Suga H, and Kageyama K. 2014. Two new species, Phytophthora nagaii sp. nov. and P. fragariaefolia sp. nov., causing serious diseases on rose and strawberry plants, respectively, in Japan. J. Gen. Plant Pathol. 80: 348–365.

Corresponding author:


from Ramhman et al. (2014)


MB 804991


nagaii = Y. Nagai, the first to isolate this oomycete


Type: JAPAN, Chiba Prefecture, from leaf and stem blight of rose (Rosa sp.), 1968, collector S. Uematsu; isolate NBRC H-13102, holotypus (freeze-dried specimen)

Ex-type: NBRC 109131 = CBS 133248

Sequences for ex-type in original manuscript: CH04PHR12 = ITS rDNA AB688356, LSU AB688499, EF1-α AB736248, β-tubulin AB736249, and coxI AB688226

Ex-type in other collections

NBRC 109131 = CBS 133248 = P19989 (WPC), CPHST BL 121 (Abad), 61H5 (Yang)

Molecular identification

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

Phytophthora nagaii isolate CPHST BL 121 (= P19989 WPC) = ITS rDNA MG865547, COI MH136940

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

Clade 7c

Morphological identification

adapted from Rahman et al. (2014)

Colonies and cardinal temperatures

Colony morphology on V-8 agar, potato dextrose agar, and malt extract agar with no distinct pattern. Minimum temperature for growth 5°C, optimum 28°C, and maximum 33°C.

Asexual phase

Sporangia nonpapillate; persistent; ellipsoid often with tapered bases (27–79 μm x 24–55 μm); proliferating internally by extended, or nested, or external proliferation; produced in single or in simple sympodial sporangiophores. Chlamydospores spherical (30–40 μm diam.), intercalary. Hyphal swellings spherical or sub-spherical (21–28 μm diam.).

Sexual phase

Homothallic. Oogonia smooth-walled (32–53 μm diam.), sometimes with tapered bases and sometimes with elongated, curved oogonial stalks; antheridia predominantly paragynous and sometimes amphigynous, generally one and occasionally two antheridia attached to the oogonium; oospores aplerotic (29–48 μm diam.).

Most typical characters

Phytophthora nagaii is characterized by the presence of intercalary chlamydospores, and spherical or sub-spherical hyphal swellings.

Additional specimen(s) evaluated

Phytophthora nagaii ex-type CPHST BL 121, duplicate of P19989 (World Phytophthora Collection), which is a duplicate of ex-type CBS 133248

Hosts and distribution

Distribution: Asia (Japan)
Substrate: leaves, stems
Disease note: blight, wilting, yellowing, defoliation
Host: Rosa odorata, Rosa sp. (Rosaceae)

Retrieved January 31, 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