Phytophthora emzansi

Name and publication

Phytophthora emzansi T. Bose, T. Paap, and J.M. Hulbert (2021)

Bose T, Hulbert JM, Burgess TI, Paap T, Roets F, Wingfield MJ. 2021. Two novel Phytophthora species from the southern tip of Africa. Mycological Progress 20 (6): 755–767.

Nomenclature

Mycobank

MB838530

Etymology

name derived from the Zulu word for south or from the south

Typification

Type: SOUTH AFRICA, Knysna Forest, Western Cape Province, from rhizosphere soil of Afrocarpus falcatus (− 33.93149201, 22.62277904), November 2017, JM Hulbert, holotype PREM63081

Ex-type: culture PPRI 28451 = CMW 54354 = CBS 147464

Sequences of ex-type in manuscript: ITS MT762301, ß-tubulin MT762318, HSP90 MT762327, coxI MT762309

Molecular identification

Position in ITS phylogenetic tree

Clade 2c

Morphological identification

Colonies and cardinal temperatures

Colony morphology cottony with no distinct pattern on MEA, CA, V8A and PDA. Minimum growth temperature 4°C, optimum 20°C, and maximum 30°C.

Conditions for growth and sporulation

Sporangia are produced in water cultures (soil extract or river water) and not observed in solid media. Oogonia are formed readily in single-strain culture on CA and V8 after about 14 d.

Asexual phase

Sporangia were semi-papillate, persistent, and predominantly ovoid in shape with no proliferation. Sporangia averaged 26.7 x 23.9 µm (overall range 25–68.3 x 17.5–41.5 µm); Sporangiophores simple or loose sympodia. Hyphal swellings present. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia had smooth walls and size ranged from 18.8–49.9 µm. Oospores plerotic, globose often with a tapering base and light golden brown on maturity, size ranged 18.2–46.7 µm. Oospores often aborted after formation of the walls. Antheridia amphigynous.

Most typical characters

Phytophthora emzansi is a sister species to P. capansis but differs mainly by the high abortion rate of oospores and in having amphigynous antheridia.

Additional specimen(s) evaluated

South Africa, Knysna Forest, Western Cape Province, from rhizosphere soil of Afrocarpus falcatus, 2017, JM Hulbert, CBS 147464; CBS 147466; 2019, CMW 54569; Eerste River, 2016, CBS 147465; from rhizosphere soil of Rapanea melanophloeos, 2019, CMW 54577; Western Cape Province, from rhizosphere soil of Podocarpus elongata, 2016, T Paap – CMW50975; Agathosma betulina, 2005, K Lubbe, STE-U 6269 (= WPC P15619, CMW 56071); STE-U 6272 (= WPC P19574, CMW 56072)

Hosts and distribution

Distribution: South Africa
Substrate: roots
Disease note: no diseases recorded
Hosts: Agathosma betulina, asymptomatically from rhizosphere soil in natural vegetation

Additional references and links

none available

Fact sheet author

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