Mycologia, 95(5), 2003, pp. 955–958.
q 2003 by The Mycological Society of America, Lawrence, KS 66044-8897
A new species of Pseudorobillarda, an endophyte from Thuja occidentalis in
Canada, and a key to the species
Montréal ( JBM); ii) mature ornamental trees in the JBM;
and iii) trees in a plantation of Villeray Recreation Park in
Montréal. The samples were brought to the laboratory within 2 h and used for fungal isolation within 6 h of collection.
From visually healthy organs, five small segments per leaf
(1 3 0.5 cm) and five per bark (1 3 0.5 cm) were taken
for fungal isolation (a total of 150 segments for the experiment). These segments were surface sterilized with 70%
ethanol for 10 s, rinsed in sterile distilled water (SDW) for
10 s, submerged for 2 min in 2% sodium hypochlorite,
washed twice in SDW for 2 min, dried on sterile filter paper
and transferred to 2% potato-dextrose agar (PDA, Becton
Dickinson, Maryland, U.S.A.) Petri plates incubated at 18 C
for approximately 4 wk in the dark.
Microscopic observations, photographs and measurement of conidiogenous cells and conidia were made in water mounts, while conidial appendages were stained using
Leifson’s modified technique (Punithalingam 1989). For
microscopic examination, conidiomata were obtained from
PDA plates after 4 wk growth in the dark at 21 C (61). Ten
conidiomata and 50 conidia from each conidioma per plate
were measured. Radial increase was measured in two directions every 24 h for 1 wk, using plates incubated at 21 C
(61) in the dark. Dimensions of fungal fertile structures
and growth rates for different isolates (one per site) are
averages from three replications.
Vladimir Vujanovic1
Marc St-Arnaud
Institut de recherche en biologie végétale and
Département de sciences biologiques, Université de
Montréal and Jardin botanique de Montréal. 4101 est,
rue Sherbrooke, Montréal, Québec, H1X 2B2 Canada
Abstract: Pseudorobillarda monica sp. nov. is described and illustrated. The endophyte was isolated
from living leaves and bark of twigs of a Thuja occidentalis bonsai (.90 years old) at the Montréal Botanical Garden and ornamental trees in Montréal urban plantations. This pycnidial fungus is typical of
the genus in morphology but clearly differs from other species in Pseudorobillarda by the distinct size of
the conidiomata and the shape and size of conidia
and paraphyses. Its taxonomic placement is discussed
and a key to the species of Pseudorobillarda is provided.
Key words:
coelomycetes, endophyte, new species, systematics
INTRODUCTION
During studies of endophytic mycobiota biodiversity
on trees in urban plantations in Montréal, Québec,
Canada, an undescribed species of the coelomycetous genus Pseudorobillarda Morelet was isolated from
living foliage of Thuja occidentalis (L.) Mill. Among
three isolates obtained, one originated from a bonsai
tree and two others were isolated from mature ornamental trees in Montréal urban plantations. The
monograph by Nag Raj (1993) and a recent publication by Bianchinotti (1997) allowed the comparison of these materials with descriptions of the nine
taxa accepted in the genus.
RESULTS
The fungus was isolated on PDA from all three sites
with an average isolation frequency for all segments
of 10.6%. Isolation differed among plant organs
(15.1% from leaves and 6.1% from bark) and type of
trees (3.9% from bonsai trees and 17.3% from ornamental trees). The colony appearance and growth
rates were similar for all isolates on tested medium.
Colony diameter increased 0.5 cm per day at 21 C,
and mature pycnidia were produced in 4 wk.
TAXONOMY
MATERIALS AND METHODS
Pseudorobillarda monica Vujanovic, sp. nov.
Asymptomatic branches (three per tree) bearing healthy foliage were collected with a pruner, mid-November 2000,
from solitary Thuja occidentalis trees. Three trees per each
of these three sites were used: i) bonsai trees, more than
90 years old (No. 3099–93), at the Jardin botanique de
FIGS. 1–7
[Foliicola et caulicola. Conidiomata pycnidia, solitaria vel
aggregaria, immersa vel semi-immersa, unilocularia vel multilocularia, globosa vel depresse-globosa, atrobrunnea 150–
400 mm lata, ostiolata; ostiola papillata, circularia vel ovalia,
20–30 mm diam; pariete 30–60 mm crasso, ex externa textura prismatica, cellulis tenuitunicatis crassitunicatis, atrobrunneis vel brunneis, et interna textura angulari, cellulis
Accepted for publication March 11, 2003.
1 Corresponding author. E-mail: vujanovv@magellan.umontreal.ca
955
956
MYCOLOGIA
FIGS. 1–7. Pseudorobillarda monica from Thuja occidentalis, HOLOTY PE (MT-TO9) on PDA: 1. Papillate ostiola. Bar 5
10 mm; 2. Vertical section of conidioma. Bar 5 25 mm; 3. Conidial mass. Bar 5 10 mm; 4. Partial sectional view of hymenium
showing paraphyses (left arrow) and conidial development (right arrow). Bar 5 5 mm; 5. Mature conidia showing appendages.
Bar 5 5 mm; 6. Enlarged view of conidia showing truncate top (up arrow) and position of oil drops (down arrow). Bar 5
5 2.5 mm; 7. Conidia showing ramification of extracellular appendages. Bar 5 2.5 mm.
pallescentibus. Conidiophora absentia. Cellulae conidiogenae
discreatae, cylindricae, circum cavitatem distributia, hyalinae, cum paraphysibus mixtae, in muco involutae, 2–10 3
2–2.5 mm. Paraphyses filiformes vel iregularies, hyalinae,
laeves, 20–35 mm long, 1–6 septatae, basi leniter inflata 2–
3 mm lat., apice 1–2.5 mm lat. Conidia bicellularia, subcylindrica vel fusiformia, in apice sub-acuta, base angusta et acuta, laevia, guttulata, 10–12 3 2.5–3.0 mm, (2–)3(–4) appen-
dices flexibiles ad apicem ferentes, 15–25 mm longas; ratione conidii long./lat.: 4.4. Coloniae in agaro ‘‘potatodextrosum’’ crescentes, ad 0.5 cm in una die ad 21 C. Mycelium denso-aerium, marginae regulari; inverso subroseus
vel brunneolus. Hyphae hyalinae, septis, 1–5 mm crassis.]
Foliicolous and caulicolous. Conidiomata pycnidial,
scattered or aggregated globose to depressed glo-
VUJANOVIC
TABLE I.
AND
ST-ARNAUD: PSEUDOROBILLARDA
SP. NOV.
957
Features differentiating Pseudorobillarda monica, P. jaczewskii and P. setariae
Characters
P. jaczewskii
P. monica
P. setariae
Conidiomata
Mean width (mm)
150
250
150
Conidial
Shape
Number of septa
Length (mm)
Width (mm)
Mean 1/w ratio
Ellipsoidal
1
15–21
3–3.5
5.4
Subcylindrical to fusiform
1
10–12
2.5–3.0
4.4
Subcylindrical to ellipsoidal
1
14–12
3–4
5
Appendages
Number
Length (mm)
2–5
10–19
2–4
15–25
2–4
9–21
Paraphyses
Septation
Length (mm)
1
30–45
1–6
20–35
1
20–43
Host
Ribes grossularia
Thuja occidentalis
bose, immersed to semi-immersed, 150–400 mm
diam, dark brown, uni- to multilocular, wall up to 30
mm thick, composed of an outer textura prismatica
with thick-walled dark brown to brown cells and an
inner textura angularis with thin-walled paler cells;
ostiolate, ostiole papilate, 20–30 mm diam. Conidiophores reduced to conidiogenous cells, lining the cavity of the conidioma, mixed with paraphyses and enveloped in mucus. Paraphyses filiform to irregular,
unbranched, 1–6 septate, hyaline, 20–35 mm long, up
to 3 mm wide at the base and 1–2 mm wide at the
apex. Conidiogenous cells short, cylindrical, hyaline,
smooth, 2–10 3 2–2.5 mm. Conidia bicellular, sometimes constricted at the septa, hyaline, subcylindrical
to fusiform, tip subacute, base narrow and acute,
smooth, guttulate, 10–12 3 2.5–3.0 mm (l/w: 4.4)
bearing at one end mostly 3, occasionally 2 or 4, unbranched, flexuous, extracellular appendices 15–25
mm long. Mycelium superficial in culture, cottony, color white to pink, radial with regular margin; reverse
first pinkish later becoming brownish; abundant
fruiting. Hyphae septate, hyaline, 1–5 mm diam.
HOLOTY PE. CANADA. QUÉBEC: Montréal, Jardin botanique de Montréal, on living foliage of Thuja
occidentalis, 11. X. 2000, Vujanovic MT-TO9 (MT,
Herbier Marie-Victorin of the University of Montreal)
dried culture.
DISCUSSION
Pseudorobillarda species are known from Argentina,
Cuba, India, Germany, Nigeria, Ukraine, United
Kingdom and the United States (Bianchinotti 1997).
This is the first report for Canada. Before this report
Oryza sativa and Setaria sp.
on Thuja occidentalis, Pseudorobillarda species have
never been found on coniferous trees, although they
are known to have a broad host ranges (Nag Raj
1993) including one broadleaf tree, Geoffroea decorticans (Gill. ex Hook. & Arn.) Burk. (Bianchinotti
1997). Whether they are pathogenic to host species
remains undetermined. However, they occur on both
living and dead leaves and stems. Uecker and Kulik
(1986) found that stems of soybean plants inoculated
with P. soyae did not show symptoms, although the
fungus was re-isolated from host tissues a few weeks
after inoculation. The nature of the association of P.
soyae can be described as endophytic. Although preliminary, this study suggests the endophytic nature of
P. monica; it was isolated from asymptomatic tree organs after rigorous surface sterilization similar to that
used for isolation of endophytes from bark (Petrini
1986) and leaf (lamina and petiole) tissues (Vujanovic and Brisson 2002).
Species in this genus are distinguished mainly by
the presence or absence of paraphyses and by conidial features, such as size and septation (Nag Raj
1993). The new proposed species differs from all
known species in the genus. The main differences
are: Pseudorobillarda sojae is characterized by the absence of paraphyses; P. texana has unicellular conidia;
P. indica and P. magna possess multiseptate conidia;
P. agrostis and P. bambusae have conidia that measure
more than 16 mm length, while P. monica conidia are
less than 12 mm long. In contrast to P. bambusae,
which shows minor conidiomata development on
PDA, Pseudorobillarda monica fructified abundantly
on this agar medium. P. monica can be distinguished
also from the two most similar paraphysate species in
958
MYCOLOGIA
the genus (P. jaczewskii and P. setariae) by size and
septation of the paraphyses, the shape and dimension of conidia and conidiomatal size (TABLE I).
Moreover, the number and length of appendages is
different. These characteristics are also of diagnostic
importance, as has been proposed by Bianchinotti
(1997). In this genus no teleomorph connections
have been made.
Sutton (1980) published a key to four species. Recently, Nag Raj (1993) presented a key to eight species. Here is a key that includes the 10 species proposed to date.
KEY TO SPECIES PSEUDOROBILLARDA
1.
1.
2.
2.
3.
3.
4.
4.
5.
5.
6.
6.
7.
7.
8.
8.
9.
9.
Paraphyses absent . . . . . . . . . . . . . . . . .
Paraphyses present . . . . . . . . . . . . . . . .
Conidia unicellular . . . . . . . . . . . . . . . .
Conidia multicellular . . . . . . . . . . . . . . .
Conidia 1-septate . . . . . . . . . . . . . . . . .
Conidia more than 1-septate . . . . . . . . . .
Mean conidium length/width ratio #5.4:1
Mean conidium length/width ratio $6.5:1
Conidia 1–3 septate . . . . . . . . . . . . . . .
Conidia 3–4 septate . . . . . . . . . . . . . . .
Paraphyses 1-septate . . . . . . . . . . . . . . .
Paraphyses 1–6 septate . . . . . . . . . . . . .
Conidiomata wall of textura angularis . .
Conidiomata wall of textura prismatica . .
Mean conidium length/width ratio 6.5:1 .
Mean conidium length/width ratio 7.8:1 .
Paraphyses unbranched . . . . . . . . . . . . .
Paraphyses branched . . . . . . . . . . . . . . .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
ACKNOWLEDGMENTS
This research was supported financially by the NSERC and
the VRQ—Plant Productivity Research Network (Quebec
Environmental Diagnostic Research Centre). Thanks also
are due to S. Hay and Herbier Marie-Victorin (MT) of the
Université de Montréal for consultation on the English text.
LITERATURE CITED
Bianchinotti MV. 1997. A new species of Pseudorobillarda
from a leguminous tree in Argentina. Mycol Res 101:
1233–1236.
Nag Raj TR. 1993. Coelomycetous Anamorphs with Appendage-Bearing Conidia., Waterloo, Ontario, Canada:
Mycologue Publications. 1101 p.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. . . P. sojae
....... 2
. . P. texana
....... 3
....... 4
....... 5
....... 6
....... 8
. . . P.indica
. . P.magna
....... 7
. P. monica
. P. setariae
P. jaczewski
....... 9
P. phragmitis
. . P. agrostis
. P. bambusae
Petrini O. 1986. Taxonomy of endophytic fungi of aerial
plant tissues. In: Fokkema NJ, van den Heuvel J, eds.
Microbiology of the phyllosphere. Cambridge, England: Cambridge University Press. p. 175–187.
Punithalingam E. 1989. Techniques for staining fungal nuclei and appendages. Botanical Journal of the Linnean
Society 99:19–32.
Sutton BC. 1980. Coelomycetes, Fungi Imperfecti with Pycnidia, Acervuli and Stromata. Kew, Surrey, England:
Commonwealth Mycological Institute. 696 p.
Uecker FA, Kulik MM. 1986. Pseudorobillarda sojae, a new
pycnidial coelomycete from soybean stems. Mycologia
78:449–453.
Vujanovic V, Brisson J. 2002. A comparative study of endophytic mycobiota in leaves of Acer saccharum in eastern
North America. Mycological Progress 1:147–154.