Name and publication
Phytophthora kernoviae Brasier, Beales & Kirk (2005)
Brasier CM, Beales PA, Kirk SA, Denman S, and Rose J. 2005. Phytophthora kernoviae sp. nov., an invasive pathogen causing bleeding stem lesions on forest trees and foliar necrosis of ornamentals in the UK. Mycol. Res. 109: 853–859.
Corresponding author: clive.brasier@forestry.gsi.gov.uk
previously known informally as Phytophthora taxon C (PtC)
Nomenclature
from Brasier et al. (2005)
Mycobank
Etymology
from ‘Kernow’, the Cornish noun for Cornwall
Typification
Type: UNITED KINGDOM, Cornwall, Caerhays, isolate from bark of Fagus sylvatica, Jan. 2004, C. M. Brasier, IMI 393170 – holotypus, dried culture on carrot agar; previously Forestry Commission Phytophthora culture collection isolate P1571
Ex-type: IMI 393170
NOTE: IMI 393170 indicates that a culture is available from CABI Collection, however a culture of IMI 393170 is not available from CABI.
Sequences for ex-type in original manuscript: Phytophthora kernoviae isolate P1571 (FCPCC) = ITS AY940661
Ex-type in other collections
P1571 (FCPCC) = IMI 393170 = P19827 (WOC/WPC), CAE4, CPHST BL 91 (Abad)
Molecular identification
Voucher sequences for barcoding genes (ITS rDNA and COI) of the ex-type (see Molecular protocols page)
Phytophthora kernoviae isolate CPHST BL 91 (= P19827 WPC) = ITS rDNA MG865521, COI MH136915
Sequences for ex-type in other sources
- NCBI: Phytophthora kernoviae CPHST BL 91
- NCBI: Phytophthora kernoviae P19827
- NCBI: Phytophthora kernoviae P1571 (FCPCC)
- Phytophthora DATABASE: Phytophthora kernoviae
- EPPO-Q-bank: Phytophthora kernoviae
- BOLDSYSTEMS: Phytophthora kernoviae (barcoding COI & ITS)
Position in ITS phylogenetic tree
Clade 10b
Morphological identification
adapted from Brasier et al. (2005)
Colonies and cardinal temperatures
Colony morphology after 7 days of growth on potato dextrose agar, malt extract agar, and V8 agar with light rosette pattern. Minimum temperature for growth is 3°C, optimum 21°C, and maximum 24°C.
Conditions for growth and sporulation
Sporangia and oospores formed in V8 cultures flooded in 10% soil solution.
Asexual phase
Sporangia papillate; caducous with medium to long pedicels (3–28 µm long); ellipsoid, ovoid, obpyriform, limoniform (19–62 L x 12–31 W µm), mouse-shaped, some with irregular shapes and some with tapered bases; most with conspicuous vacuole; originated in simple sympodial or unbranched sporangiophores. Hyphal swellings coralloid/toruloid occasionally produced. Chlamydospores absent.
Sexual phase
Homothallic. Oogonia smooth-walled, often with tapered base (22–30 µm diam); antheridia amphigynous; oospores spherical (18–28 µm diam) plerotic to slightly aplerotic.
Most typical characters
Phytophthora kernoviae is characterized by the presence of sporangia with caducous medium to long pedicel and by the presence of young oospores with thick walls.
Additional specimen(s) evaluated
Phytophthora kernoviae, ex-type CPHST BL 91, duplicate of P19827 (World Phytophthora Collection), which is a duplicate of ex-type IMI 393170
Hosts and distribution
Notes: previously reported as Phytophthora taxon C
Distribution: Europe (UK); New Zealand, South America (Chile)
Substrate: bark, leaves, shoots
Disease note: on beech, associated with bark necrosis and canker and bleeding stem lesions, especially on aerial stems; pathogenicity confirmed by inoculation studies; also associated with shoot dieback, foliar necroses, and wilting of rhododendron
Host: Fagus sylvatica (beech), Quercus robur (oak), (Fagaceae); also Liriodendron tulipifera (Magnoliaceae), Rhododendron ponticum (Ericaceae), Pinus radiata (Pinaceae)
Retrieved January 31, 2018 from U.S. National Fungus Collections Nomenclature Database.
Quarantine status
USA: Phytophthora kernoviae is listed in the National Cooperative Agricultural Pest Survey (CAPS) Priority Pest List for 2017 and 2018.
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.).
EPPO: organisms previously included in the EPPO Alert List, Phytophthora kernoviae
Additional references and links
- Phytophthora DATABASE: Phytophthora kernoviae
- EPPO-Q-bank: Phytophthora kernoviae
- SMML USDA-ARS: Phytophthora kernoviae
- EPPO Global Database: Phytophthora kernoviae
- Forest Phytophthoras of the world: Phytophthora kernoviae
- Forest Research UK: Phytophthora kernoviae
- CABI Invasive Species Compendium: Phytophthora kernoviae
- Encyclopedia of Life (EOL): Phytophthora kernoviae
- Index Fungorum (IF): Phytophthora kernoviae
- Plantwise Knowledge Bank: Phytophthora kernoviae
- Google All Phytophthora kernoviae
- Google Images Phytophthora kernoviae
- Google Scholar Phytophthora kernoviae
Fact sheet author
Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Beltsville Laboratory, United States of America