Phytophthora morindae

Name and publication

Phytophthora morindae Z.G. Abad & Nelson (2010)

Nelson S and Abad ZG. 2010. Phytophthora morindae, a new species causing black flag on noni (Morinda citrifolia L) in Hawaii. Mycologia 102: 122–134.

Corresponding author: gloria.abad@aphis.usda.gov

Nomenclature

from Nelson and Abad (2010)

Mycobank

MB 513008

Etymology

refers to the host Morinda citrifolia L.

Typification

Type: UNITED STATES OF AMERICA, from Hawaii, Island of Hawaii, from Morinda citrifolia var. citrifolia (Indian mulberry, noni), Rubiaceae (Coffee family) infected with black flag disease of noni in the Puna District (Noni Farm Road), 10 Oct 2005, collector Scot C. Nelson P238; G. Abad isolate Ph697, BPI 878721 (dried culture on baby carrot agar)

Ex-type: CBS 121982 (P238, Ph697)

Sequences for ex-type in original manuscript: Ph697, P238: ITS rDNA FJ469147, EF-1a FJ469148

Ex-type in other collections

CBS 121982 (P238, Ph697) = P19748 (WOC/WPC), CPHST BL 49G (Abad), 62B5 (Yang)

Molecular identification

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

Phytophthora morindae isolate CPHST BL 49G (= P19748 WPC) = ITS rDNA MG865543, COI MH136936

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

Clade 10b

Morphological identification

Colonies and cardinal temperatures

Colony morphology on potato dextrose agar and malt extract agar with chrysanthemum to rosette pattern, colonies on V-8 agar with fine chrysanthemum pattern. Minimum for growth 6°C, optimum 21–25°C, maximum 27°C.

Conditions for growth and sporulation

Abundant sporangia and oogonia produced in culture media.

Asexual phase

Sporangia papillate, occasionally bipapillate; caducous with medium to long pedicels (8–66 µm); ellipsoid (sometimes with tapered base), obpyriform, limoniform, or asymmetrical (bilaterally symmetrical or mouse-shaped with one rounded and one flatter side) (30–54 L x 19–24 W µm); originated in umbellate sporangiophores. Hyphal swellings absent. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia smooth-walled and frequently with tapered base (22–40 µm diam.); antheridia amphigynous (7–14 L x 6–12 W µm); oospores plerotic (21–39 µm diam.) with wall thickness 2.4–3.6 µm, immature oospores showing the presence of thick walls and mature oospores showing thinner walls; large ooplasts in mature oospores frequently present (13–20 µm diam.).

Most typical characters

The morphology of sexual reproductive structures of Phytophthora kernoviae are similar, but the umbellate sporangiophores of P. morindae differentiate it from P. kernoviae.

Specimen(s) evaluated

Phytophthora morindae ex-type CPHST BL 49G, duplicate of P19748 (World Phytophthora Collection), which is a duplicate of ex-type CBS 121982

Hosts and distribution

Distribution: USA: HI
Substrate: leaves, petioles, pedicel, fruit
Disease note: black flag disease
Host: Morinda citrifolia var. citrifolia (Rubiaceae)

Retrieved January 31, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional info
Phytophtora morindae has been reported only on Morinda citrifolia var. citrifola in Hawaii, where it is capable of causing blight on aboveground plant parts (root and stem tissue have not shown symptoms or the ability to recover the pathogen). Severely infected plants have a characteristic black flag consisting of diseased leaves. In the early stages of disease the leaves may have black streaks alongside the veins caused by rapid colonization by the pathogen. Fruit infection often occurs through the pedicel and can result in shriveled fruit mummies remaining attached to the stem.

Additional references and links

Fact sheet author

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