Phytophthora cajani (to be redescribed 2022)

Name and publication

Phytophthora cajani Amin, Baldev, & Williams (1978)

Amin KS, Baldev B, and Williams FJ. 1978. Phytophthora cajani, a new species causing stem blight on Cajanus cajan. Mycologia 70: 171–176.

Nomenclature

from Amin et al. (1978)

Mycobank

MB320473

Typification

Type: INDIA, causing stem blight on Cajanus cajan. Pure cultures have been deposited in the Phytophthora collection, Department of Plant Pathology, West Virginia University, Morgantown, U.S.A. under N516.

NOTE: Specimen N516 is lost at the Department of Plant Pathology, West Virginia University, Morgantown, USA.

Well-authenticated specimen selected by Gloria Abad:  CPHST BL 116 = P3105 (WPC)

Selected specimen(s) in other collections

CPHST BL 116 (Abad) = P3105 (WPC) = ATCC 44388, D.C. Erwin P2 from J. Kannaiyan 5, p349 (Gallegly), 45F7 (Yang)

NOTES:

ATCC 44388 as Phytophthora drechsleri var. cajani

Yang et al. 2017 incorrectly indicates that specimen 45F7 is the type of the species.

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of selected specimen(s) (see Molecular protocols page)

Phytophthora cajani isolate CPHST BL 116 (= P3105 WPC) = ITS rDNA MG783386, COI MH136859

Additional sequences for molecular identification

Phytophthora cajani isolate P3105 = ITS rDNA HQ261515, COI HQ261262

Sequences for selected specimen in other sources
Position in ITS phylogenetic tree

Clade 7b

Morphological identification

Colonies and cardinal temperatures

Colonies in CMA, V-8, and PDA with no distinctive pattern. Minimum temperature for growth 9°C, optimum 27–33°C, and maximum 36°C.

Asexual phase

Sporangia non-papillate, persistent, ovoid, obpyriform, ellipsoid, blunty ellipsoid (42–83 L x 29–46 W μm); showing internal, external, and nested proliferation; originated in unbranched sporangiophores sometimes showing swellings. Hyphal swellings terminal and intercalary with finger-like projections. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia smooth-walled (37–48 μm diam); antheridia amphyginous, some with digital projections, some bicellular; oospores aplerotic.

NOTES:

Original publication of Amin et al. (1978) indicates the presence of plerotic oospores, however the figures show oogonia with non-differentiated oospores.

Isolate P3105 is indicated as heterothallic A1 type in the WPC. Isolate CPHST-BL #116 (Abad), a duplicate of P3105, is homothallic and produced oospores in single culture in our laboratory (G. Abad 9/17/16).

Most typical characters

Phytophthora cajani is characterized by the presence of marked aplerotic oospores.

Specimen evaluated

Phytophthora cajani CPHST BL 116 (Abad) = P3105 [World Phytophthora Collection (WPC) California, USA]

Hosts and distribution

Distribution: Asia (India)
Substrate: stems, also on branches, petioles, leaves. Roots are not attacked.
Disease note: stem rot and blight
Hosts: Cajanus cajani (Fabaceae)

Retrieved January 29, 2018 from U.S. National Fungus Collections Nomenclature Database.

Quarantine status

USA: This species was listed as a species of concern during the 2009 Phytophthora prioritization project conducted by USDA APHIS PPQ CPHST PERAL (Schwartzburg et al.).

Additional references and links

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

Fact sheet author

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