Citizen science project reveals high diversity in Didymellaceae (Pleosporales, Dothideomycetes)
Author
Hou, Lingwei
Author
Hernandez-Restrepo, Margarita
Author
Groenewald, Johannes Zacharias
Author
Cai, Lei
Author
Crous, Pedro W.
text
MycoKeys
2020
65
49
99
http://dx.doi.org/10.3897/mycokeys.65.47704
journal article
http://dx.doi.org/10.3897/mycokeys.65.47704
1314-4049-65-49
DED2BF86E6FD56179642F7119604CEB9
Ascochyta benningiorum Hern.-Restr., L. W. Hou, L. Cai & Crous
sp. nov.
Figure 2
Etymology.
benningiorum
refers to Eva, Bas & Anne Benning who collected the soil sample from which the ex-type strain was isolated.
Typus.
The Netherlands. Gelderland province, Wijchen, isolated from garden soil, Mar. 2017, E. Benning, B. Benning & A. Benning (
holotype
designated here CBS H-24104, living ex-type culture CBS 144957 = JW 196005).
Conidiomata
pycnidial, mostly solitary, sometimes confluent, globose or subglobose, irregularly-shaped with age, brown to dark brown, glabrous, mostly produced on the agar surface and some immersed, 140-480(-580)
x
100-370(-440)
μm
; with 1-6(-10) slightly papillate ostioles; pycnidial wall pseudoparenchymatous, 4-8 layers, 14.5-65
μm
thick, outer layers composed of brown, flattened polygonal cells of 11-28
μm
diam.
Conidiogenous cells
phialidic, hyaline, smooth, globose, ampulliform to lageniform, 5.5-9
x
4-6.5
μm
.
Conidia
cylindrical, hyaline, smooth- and thin-walled, mostly straight, occasionally curved, aseptate, (3.5-)4.5-7
x
1.5-2.5
μm
, 2-guttulate, small.
Conidia
matrix
whitish.
Culture characteristics.
Colonies after 7 d at 25 °C, on OA reaching 50-55 mm diam, aerial mycelium floccose, olivaceous to olivaceous black, buff towards the periphery, abundant production of pycnidia, margin irregular; reverse concolorous with the surface. On MEA reaching 40-45 mm diam, aerial mycelium floccose, concentric circles, centre pink, grey olivaceous, mouse grey, rosy buff toward periphery, moderate production of pycnidia, margin irregular; reverse orange, olivaceous black toward periphery. On PDA reaching 45-50 mm diam, aerial mycelium floccose, dark brick to olivaceous grey, buff towards periphery, abundant production of pycnidia, margin irregular; reverse concolorous with the surface. NaOH spot test negative on OA.
Additional specimens examined.
The Netherlands. Gelderland province, Wijchen, isolated from garden soil, Mar. 2017, E. Benning, B. Benning & A. Benning, JW 196023 = CBS 144958; ibid. JW 196013.
Notes.
Ascochyta benningiorum
is represented in the phylogenetic tree by three isolates (CBS 144957, CBS 144958 and JW 196013) from the same soil sample collected in Wijchen (Gelderland province).
Ascochyta benningiorum
grouped in a distinct clade close to
A. phacae
(Figure
1
). However, it morphologically differs from
A. phacae
by having smaller (3.5-7
x
1.5-2.5
μm
) and aseptate conidia. In
A. phacae
the conidia are 7-10
x
2-4
μm
and 0-1-septate (
Corbaz 1955
).
Species in
Ascochyta
are commonly regarded as plant pathogens, especially of cereal crops and legumes (
Davidson and Kimber 2007
;
Tivoli and Banniza 2007
), and only a few species were reported from soil, namely
A. fabae
,
A. lentis
,
A. pisi
,
A. rabiei
(
Gossen and Morrall 1986
;
Tivoli and Banniza 2007
) and
A. syringae
in the current study. Nevertheless,
A. benningiorum
is phylogenetically and morphologically distinct from these species (Figure
1
;
Chen et al. 2015
).
Figure 2.
Ascochyta benningiorum
(CBS 144957).
A, B
Colony on OA (front and reverse)
C, D
colony on MEA (front and reverse)
E, F
colony on PDA (front and reverse)
G
pycnidia forming on OA
H
pycnidium
I
section of pycnidium
J
section of pycnidial wall
K-M
conidiogenous cells
N
conidia. Scale bars: 100
μm
(
H, I
); 10
μm
(
J
); 5
μm
(
K-N
).