Phytophthora podocarpi

Name and publication

Phytophthora podocarpi K. Dobbie, R.L. McDougal & P.M. Scott (2022)

Dobbie K, Scott P, Taylor P, Panda P, Sen D, Dick M, McDougal R. 2022. Phytophthora podocarpi sp. nov. from siseased needles and shoots of Podocarpus in New Zealand. Forests 13 (2): 214

Nomenclature

Mycobank

MB841407

Etymology

‘podocarpi’ refers to Podocarpus, the host genus of this oomycete

Typification

Type: NEW ZEALAND, Gisborne, Hampton Forest, from needles of Podocarpus totara, July 2011, BJ Rogan. holotype NZFRIM 5991

Ex-type: ICMP 24118 = NZFS 3642

Sequences of ex-type in manuscript: genome sequence GenBank LGSN00000000

Molecular identification

Position in ITS phylogenetic tree

Clade 15

Genome sequence

Phytophthora podocarpi strain ex-type NZFS 3642. Accession genome NZFS3642v1 reference, BioProject PRJNA290788, University of Exeter (2015), Studholme et al. 2015

Morphological identification

Colonies and cardinal temperatures

Very slow growing, slightly felted with slight striate pattern on CA. Minimum growth temperature 2°C, optimum 17°C, and maximum 25°C.

Conditions for growth and sporulation

Sporangia are produced after 24–36 h in pond water. Oogonia rare in single-strain culture on CA and V8 after about 8 weeks.

Asexual phase

Sporangia were non to semi-papillate, both persistent and caducous, and predominantly ovoid in shape with no proliferation. Sporangia averaged 55.7 x 37 µm (overall range 47.6–64.5 x 31.3–41.1 µm). Sporangiophores simple or loose sympodiaHyphal swellings present. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia had smooth walls and size ranged from 25–30 µm Oospores plerotic, globose often with a tapering base and light golden brown on maturity, size ranged 22–27 µm. Oogonial stalk often globose, occasionally with digitate projections. Antheridia absent or paragynous.

Most typical characters

In phylogenetic analysis, P. podocarpi falls between clade 3 and clade 5 and has been placed in the new clade 15 along with Perenospora hyoscyami

Additional specimen(s) evaluated

New Zealand, Gibsborne, Hampton Forest, Western Cape Province, from needles of Podocarpus totara, 2011, NZFS 3603, NZFS 3645, NZFS 3768; Gisborne, Mata Forest, 2012, NZFS 3702; 2014, NZFS 4074; Northland, Pipiwai Forest, 2012, NZFS 3727; Taranaki, Otunui Forest, 2017, NZFS 4473; Hawkes Bay, Crystals Forest, 2017, NZFS 4525; Bay of Plenty, Kinleith Forest, NZFS 4526

Hosts and distribution

Distribution: New Zealand
Substrate: leaves (needles)
Disease note: needle and shoot blight of Podocarpus totara
Host: Podocarpus totara

Additional references and links

none available

Fact sheet author

Treena Burgess, Ph.D., Phytophthora Science and Management, Harry Butler Institute, Murdoch University