Name and publication

Phytophthora acaciae A.F. dos Santos, T.C.A. Alves, D.J. Tessmann, K.L. Ivors & J.B. Ristaino (2019)

Alves TC, Tessmann DJ, Ivors KL, Ristaino JB, Dos Santos ÁF. 2019. Phytophthora acaciae sp. nov., a new species causing gummosis of black wattle in Brazil. Mycologia 4 111 (3): 445–455.

Corresponding author: Dauri J. Tessmann; djtessmann@uem.br

Nomenclature

Mycobank

MB823684

Etymology

“acaciae” referring to the genus of the host plant

Typification

Type: BRAZIL, Rio Grande Do Sul, Triunfo, 29°54′21.34″S, 51°42′27.05″W, 36 m alt, dried culture isolated from black wattle trunk, 12 Nov 1999, A. F. Santos, holotype MBM 415188.

Ex-type: culture AN02

Sequences for ex-type in original manuscript:  ITS KX396303, cox1 KX396267, cox2 KX396279, β-tubulin KX396338, RAS KX396313, TEF1α = KX396326

Ex-type in other collections

(ET) AN02

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of the ex-type (see Molecular protocols page)

Phytophthora acaciae ITS rDNA, COI

Voucher sequences for Molecular Toolbox with seven genes (ITS, β-tub, COI, EF1α, HSP90, L10, and YPT1 

(see Molecular protocols page) (In Progress)

Voucher sequences for Metabarcoding High-throughput Sequencing (HTS) Technologies [Molecular Operational Taxonomic Unit (MOTU)]

(see Molecular protocols page) (In Progress)

Sequences with multiple genes for ex-type in other sources

• NCBI: Phytophthora acaciae
• EPPO-Q-bank: Phytophthora acaciae
• BOLDSYSTEMS: Phytophthora acaciae

Position in multigenic phylogeny with 7 genes (ITS, β-tub, COI, EF1α, HSP90, L10, and YPT1)

Clade clade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
2e

Morphological identification

Colonies and cardinal temperatures

Colony colony:
assemblage of hyphae which usually develops form a single source and grows in a coordinated way
morphology cottony with rosaceous pattern on CA. Minimum growth temperature 6°C, optimum 18–24°C, and maximum 36°C.

Conditions for growth and sporulation

SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
produced on 10% soil extract under constant light. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are formed readily on CA after 5 days when pair with opposite mating typemating type:
molecular mechanisms that regulate compatibility in sexual reproduction in heterothallic species (also referred to as compatibility type); typically denoted as A1 or A2
.

Asexual phase

SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
were papillatepapillate:
pertaining to the production of a distinct papilla at the distal end of the sporangium (cf. nonpapillate and semipapillate)
, non-caducous, and predominantly ellipsoidellipsoid:
refers to a solid body that forms an ellipse in the longitudinal plane and a circle in cross section; many fungal spores are ellipsoidal or elliptic
in shape. SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
averaged 51 x 31 µm (overall range 28–85 x 21–50 µm); Sporangiophores simple or loose sympodia; Hyphal swellings absent. ChlamydosporesChlamydospores:
an asexual spore with a thickened inner wall that is delimited from the mycelium by a septum; may be terminal or intercalary, and survives for long periods in soil
present, abundant.

Sexual phase

Heterothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
smooth-walled, size ranged from 20–34 µm. OosporesOospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
apleroticaplerotic:
pertaining to a mature oospore that does not fill the oogonium; i.e. there is room left between the oospore wall and oogonium wall (cf. plerotic)
, thick-walled, size ranged 17–30 µm. AntheridiaAntheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
amphigynousamphigynous:
pertaining to the sexual stage in which the antheridium completely surrounds the stalk of the oogonium (cf. paragynous)
.

Most typical characters

Morphologically similar to other species in Cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
2d.

Additional specimen(s) evaluated

Brazil, Rio Grand so Sul, Triunfo, from Acacia mearnsii trunk canker, AN05; AN12; AN13; AN14; AN23; AN905; AN906; AN907; AN908; AN909; AN910; AN911; AN912; AN913; AN914; AN915; AN916; Piratini, from Acacia mearnsii trunk canker, AN72; AN73; AN74; AN74B; AN87; AM5

Hosts and distribution

Distribution: Brazil
Substrate: trunk
Disease note: trunk lesions accompanied by gummosis or no gum exudation, from the trunk base to ~1.5 m of 2–6-year-old Acacia mearnsii commercial plantations
Host: Acacia mearnsii

Additional references and links

• SMML USDA-ARS: Phytophthora acaciae
• EPPO Global Database: Phytophthora acaciae
• Forest Phytophthoras of the World: Phytophthora acaciae
• CABI Digital Library: Phytophthora acaciae
• Encyclopedia of Life (EOL): Phytophthora acaciae
• Index Fungorum (IF): Phytophthora acaciae

Fact sheet author

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

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Plant Pathogen Confirmatory Diagnostics Laboratory (PPCDL), United States of America