Phytophthora multibullata

Name and publication

Phytophthora multibullata Q.N. Dang and T. I. Burgess (2021)

Dang QN, Pham TQ, Arentz F, Hardy GE, Burgess TI. 2021. New Phytophthora species in clade 2a from the Asia-Pacific region including a re-examination of P. colocasiae and P. meadii. Mycological Progress 20 (2): 111–129.

Nomenclature

Mycobank

MB836441

Etymology

referring to the characteristic vesicles observed in the antheridia

Typification

Type: VIETNAM, Yen Bai, Van Yen, rhizosphere soil from Cinnamomum cassia plantations, Sep. 2018, Q.N. Dang, holotype MURU489

Ex-type: CBS 146552

Sequences of ex-type in manuscript:  ITS MT568655, β-tubulin MT583643, hsp90 MT583684, cox1 MT583658, cox2 MT583673, nadh1 MT583700, rps10 MT583719

Molecular identification

Position in ITS phylogenetic tree

Clade 2a

Morphological identification

Colonies and cardinal temperatures

Colony morphology cottony and stellate on CA, dense and stellate on PDA, smooth and thin on MEA, and submerged and stellate on V8A. Minimum growth temperature 4°C, optimum 30°C, and maximum 32.5°C.

Conditions for growth and sporulation

Sporangia are produced in water cultures (soil extract) and not observed in solid media. Oogonia are formed readily in paired cultures on V8A after about 21 d.

Asexual phase

Sporangia were semi-papillate to papillate, mostly persistent, and predominantly ovoid in shape with no proliferation. Sporangia averaged 48.6 x 31.1 µm (overall range 21–105 x 14.4–43.2 µm). Sporangiophores simple. Hyphal swellings present. Chlamydospores present.

Sexual phase

Heterothallic. Oogonia had smooth walls and size ranged from 20–26 µm. Oospores plerotic to semi-aplerotic, globose, size ranged 18.5–21.5 µm. Oospores often aborted after formation of the walls. Antheridia amphigynous with many small vesicles.

Most typical characters

Phytophthora multibullata resides in clade 2a and is most closely related to P. citrophthora; these species are morphologically very similar. The vesicles within the antheridia are the most distinguishing feature. Many sequences on Genbank assigned to P. citrophthora have 100% similarity with P. multibullata.

Additional specimen(s) evaluated

Viet Nam, Yen Bai, Van Yen, rhizosphere soil from Cinnamomum cassia plantations, 2018, Q.N. Dang, QD49; QD05

Hosts and distribution

Distribution: Vietnam
Substrate: roots
Disease note: root rot of Cinnamomum cassia, in conjunction with P. cinnamomi
Host: Cinnamomum cassia

Additional references and links

none available

Fact sheet author

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