Phytophthora marrasii

Name and publication

Phytophthora marrasii Bregant, Rossetto, and Linaldeddu (2021)

Bregant C, Rossetto G, Deidda A, Maddau L, Franceschini A, Ionta G, Raiola A, Montecchio L, Linaldeddu BT. 2021. Phylogeny and pathogenicity of Phytophthora species associated with artichoke crown and root rot and description of Phytophthora marrasii sp. nov. Agriculture 9: 873.

Nomenclature

Mycobank

MB840582

Etymology

in honour and memory of Professor Francesco Marras for his outstanding work on globe artichoke diseases

Typification

Type: ITALY: Samassi, isolated from a globe artichoke root, 17 February 2021, collected by B.T. Linaldeddu, isolated by Carlo Bregant, HOLOTYPE CBS H-24776, a dried culture on CA

Ex-type: culture CBS 148033 = CB150

Sequences for ex-type in original manuscript:  ITS MZ569854, β-tubulin MZ603724, cox1 OK054535

Molecular identification

Position in ITS phylogenetic tree

Clade 8

Morphological identification

Colonies and cardinal temperatures

Colony morphology cottony on PDA, stellate on MEA, and rosaceous to stellate on CA. Minimum growth temperature <2°C, optimum 13°C, and maximum 28°C.

Conditions for growth and sporulation

Sporangia produced on pond water with Quercus suber roots after 36-72 hours. Oogonia are formed abundantly in single culture when flooded with pond water.

Asexual phase

Sporangia were non-papillate, persistent, and predominantly ovoid to ellipsoid in shape with external and internal proliferation, both nested and extended. Sporangia averaged 74 x 31 µm (overall range 48–132 x 21.6–41.6 µm); Sporangiophores simple. Hyphal swellings present. Chlamydospores present.

Sexual phase

Homothallic. Oogonia smooth-walled, average size 30.7 µm. Oospores aplerotic, average size 28.4 µm. Antheridia amphigynous.

Most typical characters

In multiple gene phylogenies P. marrasii is placed within clade 8, but it does not cluster with any of the currently defined clades. Rather, it is basal to Clades 8b and 8d.

Additional specimen(s) evaluated

ITALY: Samassi, isolated from rhizosphere and fine roots of a globe artichoke plant, 17 February 2021, collected by B.T. Linaldeddu, isolated by Carlo Bregant; CB149

Hosts and distribution

Distribution: Italy
Substrate: root and crown rot
Disease note: represented by stunted growth, wilting and necrosis of basal leaves, dark brown discoloration of stem tissues, and crown and root rot
Host: Cynara cardunculus var. scolymus (globe artichoke)

Additional references and links

none available

Fact sheet author

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