Phytophthora mengei

Name and publication

Phytophthora mengei Browne, Gallegly & Hong (2009)

Hong CX, Gallegly ME, Browne GT, Bhat RG, Richardson PA, and Kong P. 2009. The avocado subgroup of Phytophthora citricola constitutes a distinct species, Phytophthora mengei sp. nov. Mycologia 101: 833–840.

Corresponding author: C. Hong chhong2@vt.edu

Nomenclature

from Hong et al. (2009)

Mycobank

MB513047

Etymology

refers to the originator (Dr John Menge) of the type culture and eight additional avocado isolates used in this study

Typification

Type: UNITED STATES, California, isolated from Persea americana by J. Menge (date unknown), ATCC MYA-4554 a cryopreserved specimen of M218.z1

Ex-type: ATCC MYA-4554 (= mengei ET.CH-2008b.42B2 STRAIN 42B2)

Sequences for ex-type in original manuscript: CH-2008b isolate 42B2 = ITSrDNA: EU748545

Ex-type in other collections

ATCC MYA-4554 = P16862 (WOC/WPC), CPHST BL 31 (Abad), p340 [42B2, M218.z1], 42B2 (Yang)

Molecular identification

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

Phytophthora mengei isolate CPHST BL 31 (= P16862 WPC) = ITS rDNA MG865539, COI MH136932

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

Clade 2

Morphological identification

Colonies and cardinal temperatures

Colony morphology after 7 days of growth on V8 agar, potato dextrose agar, and malt extract with no distinct pattern to slightly radiate. Minimum temperature for growth is 6°C, optimum 25°C, and maximum 33°C.

Asexual phase

Sporangia semipapillate; persistent; ellipsoid, ovoid, and irregular shapes, ellipsoid sporangia sometimes with a constriction in the middle (37–95 L x 27–44 W µm.); empty sporangia have a small plug at the point of pedicel attachment. Sporangia produced in simple sympodial or in single long sporangiophores. Hyphal swellings rarely produced. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia spherical (20–27 µm diam.) some with tapered stalks or with a slight hook in the taper; antheridia paragynous and commonly asymmetrically capitate; oospores predominantly plerotic (19–25 µm diam.) or slightly aplerotic.

Most typical characters

Phytophthora mengei is characterized by the presence of oogonia with tapered stalks with a slight hook in the taper.

Specimen(s) evaluated

Phytophthora mengei ex-type CPHST BL 31 = P16862 (World Phytophthora Collection)

Hosts and distribution

Distribution: North America (USA: CA)
Substrate: trunks, roots, fruits
Disease note: canker
Host: Persea americana (Lauraceae)

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