ACTA MYCOLOGICA
Vol. 42 (1): 119-123
2007
Dedicated to Professor Alina Skirgiełło
on the occasion of her ninety-fifth birthday
New Phoma species on Leonurus cardiaca
BEATA ZIMOWSKA
Department of Plant Pathology, Agricultural University
Leszczyńskiego 7, PL-20-069 Lublin
beata.zimowska@ar.lublin.pl
Z i m o w s k a B.: New Phoma species on Leonurus cardiaca. Acta Mycol. 42 (1):119-123, 2007.
Two species of Phoma obtained from motherwort Leonurus cardiaca L., during mycological
analyses attendant upon three-years study connected healthiness of the plants. Isolates of
Phoma capitulum were obtained from roots, whereas Phoma septicidalis from roots and leaves.
Description in vitro, photos of morphological structures and distribution of Phoma spp. are
given. This is the first report of P. capitulum and P. septicidalis on motherwort in Poland.
Key words: Phoma, occurrence, morphology, Leonurus cardiaca
InTrODUcTIOn
Phoma spp. (Sphaeropsidales) constitute a group of fungi with very differentiated biological specialization (M a r c i n k o w s k a 1995). They include saprophytic
species, developing on different substrata, secondary pathogens of plants with polyphagous character of parasitism and specific pathogens of cultivated plants. The
group of plants from which fungi from genus Phoma were isolated includes for
example herbaceous plants (M a c h o w i c z -S t e f a n i a k et al. 2002; M a c h o w i c z -S t e f a n i a k et al. 2004). Phoma dictamnicola Boerema, de Gruyter et Noordel.,
P. glaucii Brun., P. multirostrata var. microspora (Allescher) Boerema from the
leaves, stems and roots of common thyme, while P. eupatorii Died. was obtained
from creemocarps (M a c h o w i c z -S t e f a n i a k , Z i m o w s k a 2000; M a c h o w i c z -S t e f a n i a k et al. 2002). P. exigua var. exigua Desm. and P. glomerata (Corda)
Wollenw. et Hochapf. were isolated from the roots, stems and leaves of common
thyme, common balm and St. John’s wort (Z i m o w s k a , M a c h o w i c z -S t e f a n i a k
2004; M a c h o w i c z -S t e f a n i a k et al. 2004). Isolates of P. strasseri Moesz. were obtained from the stems and rhizomes of peppermint showing the signs of black rot
(Z i m o w s k a , M a c h o w i c z -S t e f a n i a k 2005).
In recent years the species of Phoma capitulum Pawer, Mathur et Thirumalachar (P. ostiolata var. ostiolata Pawer, Mathur et Thirumalachar, P. ostiolata var.
brunnea Pawer, Mathur et Thirumalachar) as well as Phoma septicidalis Boerema
120
B. Zimowska
(Pyrenoacheta telephii Alesch., Phoma telephii (Vestergr.) Kestern), which have not
been described earlier, on this plant, have been isolated from Leonurus cardiaca L.
(d e G r u y t e r , N o o r d e l o o s 1992; d e G r u y t e r , B o e r e m a 2002). In accessible literature these species are enumerated as commonly occurring saprotrophs
developing on different substrata, and P. septicidalis can also cause necrosis of the
leaves of plants from the family Gramineae (d e G r u y t e r , N o o r d e l o o s 1992; d e
G r u y e r , B o e r e m a 2002).
Considering the key importance of Phoma spp. morphology, with the proper
differentiation of taxa, the present paper deals with the identification of the enumerated two species of fungi made on the basis of thorough studies of macro- and
microscopic properties of these organisms in cultures in vitro.
MATErIAL AND METHODS
The study material consisted of isolates Lc 186, Lc 259, Lc 368, Lc 544 and Lc 56
P. capitulum obtained from the roots and isolates Lc 238, Lc 79, Lc 139 and Lc 225 P.
septicidalis from the roots and leaves of 2-year-old motherwort. The fungi cultures
used were obtained as a result of the mycological analysis (Z i m o w s k a , M a c h o w i c z -S t e f a n i a k 2004) accompanying the three-year-long studies (2004-2006) on
plants’ healthiness that were conducted on production plantation in the communes
of Fajsławice and Dziecinin in the Lublin district (Z i m o w s k a unpublished).
Identification of the obtained isolates and the taxa they belong to was carried out
on the basis of a thorough analysis of morphological structures, macroscopic properties of colonies and biochemical features conducted in vitro on standard media
(maltose MA, oat agar OA and cherry agar CA) after 7 and 14 days of incubating the
cultures in a thermostat at the temperature of 22oC (d e G r u y t e r , N o o r d e l o o s
1992; Z i m o w s k a , M a c h o w i c z -S t e f a n i a k 2005). The studied fungi cultures
were marked on the basis of a monograph by d e G r u y t e r and N o o r d e l o o s
(1992) and d e G r u y t e r and B o e r e m a (2002).
rESUlTS
The studies conducted on the growth of the analyzed isolates of P. capitulum on
standard media showed that the cultures of the fungus on MA after 7 days reached
the diameter of 38-40 mm, while after 14 days 75 mm. The hyphae of the air mycelium formed a flocky structure of white or light olive-grey colour. The reverse
was peach-salmon colour. The edge of cultures of all the studied isolates was characterized by regular growth. The growth of P. capitulum isolated on OA was slightly
poorer than on MA since the diameter of the colony measured after 7 days was 36
mm, while after 14 days it ranged from 65 to 70 mm. The colonies were white-creamy
with a salmon reverse, while the hyphae of the air mycelium formed a velvet-flocky
structure. The smallest diameter of colonies was observed on medium CA. After 7
days it ranged from 27 to 29 mm, while after 14 days – from 53 to 58 mm. In the case
of most isolates, on this medium the edge of a colony was characterized by irregular
growth. The hyphae of the air mycelium were white and they formed a flocky structure. The reverse of the colony was of light salmon colour.
121
Phoma species on Leonurus cardiaca
Numerous pycnidia on OA centered in concentric circles or sectors. They were
round, olive to olive-black, mostly smooth or covered with scarce hyphal outgrowths
(Fig. 1). From 1 to 3 ostioles, from which grey conidial exudates, were observed on
the surface of the pycnidia. The latter were mostly formed on the surface of agar
or they were partly immersed in it. Their size was from 50 to 100 μm, on average
(Tab. 1). The conidia were hyaline, round or slightly ellipsoidal, and they contained
1 to 2 guttules, their size ranging from 3.7 to 2.5 μm (Fig. 2, Tab. 1). In the case of
all the studied isolates of P. capitulum, the reaction with 1N NaOH was negative.
Besides, none of the isolates formed chlamydospores.
After 7 days of growth P. septicidalis isolates on MA medium formed colonies
with the diameter ranging from 20 to 38 mm, while after 14 days the diameter ranged
from 41 to 70 mm. The hyphae of the air mycelium formed a compact felt-like structure of rosy-wine colour and the reverse of the same colour. A slightly bigger diameter was observed in the case of the growth of the colonies of P. septicidalis isolates
on OA medium. After 7 days it ranged from 21 to 40 mm, while after 14 days – from
50 to 57 mm. The structure of the air mycelium was the same as on MA medium.
The central part of the colony was olive-grey, while the edge had rosy-wine colour. On CA medium the fungus colonies reached the diameter from 20 to 29 mm
after 7 days, while after 14 days it ranged from 40 to 60 mm. The structure of the
Ta b l e 1
Characteryzation of pycnidia and conidia of Phoma capitulum and Phoma septicidalis
(mean for 5 isolates)
P. capitulum
Author
Pycnidia
P. septicidalis
Conidia
Pycnidia
Conidia
shape and
dimension
in μm
arrangement
and structure
of walls
surface
shape and
dimension
in μm
shape and
dimension
in μm
arrangement
and structure
of walls
surface
shape and
dimension
in μm
Own data
globose
with 1 to 3
ostioles,
50 – 100
on the agar
in concentric
zones or
sectors, with
softly hyphal
outgrowts
globose
to shortly
ellipsoid,
with 1 to 2
guttules,
3.7 x 2.5
globose
with 1 to 2
ostioles
65-160
mainly on the
agar but also
in the agar,
long setae
spread over
the surface
ellipsoidal
with several
small
guttules, 4.4
x 2.2
de Gruyter
and
Noordeloos
1992
globose
with 1 to
3 ostioles,
60-105
mostly on
the agar but
also partly
or entirely in
the agar in
concentric
zones or
sectors,
with hyphal
outgrowts
broadly
and shortly
ellipsoid
with 1 to 2
guttules, 3.8
x 2.6
globose to
subglobose
with 1 to
2 ostioles,
70-170
mainly on
the agar,
with long
setae spread
mainly over
the upper
surface
subglobose
to
ellipsoidal
with several
small
or large
guttules, 4.5
x 2.3
de Gruyter
and
Boerema
2002
122
B. Zimowska
air mycelium, the colour of the obverse and the reverse was similar to the colonies
growing on OA medium. The edge of the studied isolates of P. septicidalis on all the
three media was characterized by irregular growth.
Detailed observations on OA medium showed that the pycnidia of the studied
fungus isolates got formed individually or in small groups. They were most frequently round, honey-olive to black-olive one, and their walls were covered by very numerous setae with the length ranging from 180 to 210 μm (Fig. 3, Tab. 1). 1 to 2 ostioles,
from which white drops of conidial exudates, were observed on the surface of the
pycnidia. The size of the pycnidia ranged from 65 to 160 μm (Tab. 1). The conidia
were hyaline, 1-cell, ellipsoidal, with a few gutteles with the dimensions of 4.4 x 2.2
μm (Fig. 4, Tab. 1). In the case of all the studied isolates of P. septicidalis, the studies observed a positive reaction with 1N NaOH on MA and OA media. The edge
of the colonies was of violet-purple. Besides, fragmentation of the mycelium cells
characteristic of this species was visible on the hyphae of the mycelium, especially
in older cultures (Fig. 5). None of the studied isolates of the fungus formed chlamydospores.
DIScUSSIOn
Thanks to the studies in vitro on the morphology of pycnidia and conidia and on
the character of the growth of the analyzed cultures it was possible to distinguish two
discussed species of Phoma and classify them into the proper sections. results of the
studies as compared to the descriptions contained in the monographs of fungi from
the genus Phoma made it possible to place P. capitulum isolates in part I of Phoma
section since they include studies on taxa with very small dimensions of conidia, with
the length not exceeding 5.5 μm (d e G r u y t e r , N o o r d e l o o s 1992). Although the
dimensions of the conidia in fungi from genus Phoma play a secondary diagnostic
importance (D o r e n b o s c h 1970), in the case of the species belonging to Phoma
section this property acquires a special significance due to the division of this section
into three parts performed on the basis of the conidia dimensions (d e G r u y t e r ,
N o o r d e l o o s 1992; d e G r u y t e r et al. 1993; d e G r u y t e r et al. 1998). On the basis of a detailed analysis of morphological structures, especially pycnidia, the studied
isolates of P. septicidalis were classified into the section of Paraphoma. A characteristic feature of the species described by the Dutch mycologists is the formation of
pycnidia with the walls covered with setae, which are formed on their whole surface
or they occur only around the ostiole (d e G r u y t e r , B o e r e m a 2002).
The conducted studies confirmed the correctness of the assumption presented
in the 1930’s and 1940’s by Woollenweber, Hochapfel and Dennis (D e n n i s 1946),
and later continued by the mycologists from a Dutch Station of Plant Protection in
Wageningen (B o e r e m a , B o l l e n 1975) that defining the taxa within Phoma spp.
is possible only on the basis of constant morphological features that are observed in
vitro in the cultures developing in standard conditions.
Phoma species on Leonurus cardiaca
123
rEFErEncES
B o e r e m a G. H., B o l l e n G. J. 1975. Conidiogenesis and conidial septation as differentiating criteria
between Phoma and Ascochyta. Persoonia 8: 111–144.
D e n n i s r. W. G. 1946. Notes on some British fungi ascribed to Phoma and related genera. Trans. Br.
Mycol. Soc. 29: 11–42.
D o r e n b o s c h M . M . J . 1970. Key to nine ubiquitous soliborne Phoma- like fungi. Persoonia 6:
1–14.
G r u y t e r J . d e , N o o r d e l o o s M . E . 1992. Contributions towards a monograph of Phoma (Coelomycetes) I. 1. Section Phoma: Taxa with very small conidia in vitro. Persoonia 15 (1): 71–92.
G r u y t e r J . d e , N o o r d e l o o s M . E . , B o e r e m a G . H . 1993. Contributions towards a
monograph of Phoma (Coelomycetes) I. 2. Section Phoma: Additional taxa with very small conidia
and taxa with conidia up to 7 μm long. Persoonia 15 (3): 369–400.
G r u y t e r J . d e , N o o r d e l o o s M . E . , B o e r e m a G . H . 1998. Contributions towards a monograph of Phoma (Coelomycetes)-I. 3. Taxa with conidia longer than 7 μm. Persoonia 16 (4): 471-490.
G r u y t e r J . d e , B o e r e m a G . H . 2 0 0 2 . Contributions towards a monograph of Phoma (Coelomycetes) VIII. Section Paraphoma: Taxa with setose pycnidia. Persoonia 17 (4): 541–561.
M a c h o w i c z - S t e f a n i a k Z . , Z i m o w s k a B . 2000. Grzyby przenoszone przez nasiona ro�lin zielarskich. Acta Agrobot. 53 (2): 25–38.
M a c h o w i c z - S t e f a n i a k Z . , Z i m o w s k a B . , Z a l e w s k a E . 2002. Grzyby zasiedlające różne
organy tymianku wła�ciwego Thymus vulgaris L. uprawianego na Lubelszczyźnie. Acta Agrobot.
55 (1): 185–197.
M a c h o w i c z - S t e f a n i a k Z . , Z a l e w s k a E . , Z i m o w s k a B . 2004. Grzyby zasiedlające
nadziemne organy melisy lekarskiej (Melissa officinalis L.) i tymianku wła�ciwego (Thymus vulgaris
L.) uprawianych na Lubelszczyźnie. Folia Univ. Agric. Stein., Agriculture 239 (95): 229–232.
M a r c i n k o w s k a J . 1995. Nowoczesne spojrzenie na systematykę rodzaju Phoma. Wiad. Bot. 39 (3/4):
47–52.
Z i m o w s k a B . , M a c h o w i c z - S t e f a n i a k Z . 2004. Grzyby zagrażające uprawie dziurawca zwyczajnego (Hypericum perforatum L.) w województwie lubelskim. Acta Sci. Pol., Hortorum Cultus
3 (1): 61–74.
Z i m o w s k a B . , M a c h o w i c z - S t e f a n i a k Z . 2005. Charakterystyka izolatów Phoma strasseri
nie notowanego w Polsce patogenu mięty pieprzowej (Mentha piperita L.). Acta Agrobot. 58 (2):
151–162.
Nowe gatunki z rodzaju Phoma na serdeczniku pospolitym
Streszczenie
Podczas analizy mikologicznej towarzyszącej trzyletnim badaniom (2004-2006), nad zdrowotno�cią ro�lin serdecznika pospolitego (Leonurus cardiaca), uzyskano nie opisywane wcze�niej na tej ro�linie gatunki z rodzaju Phoma. Izolaty Phoma capitulum wyosobniono z korzeni,
za� Phoma septicidalis z korzeni i li�ci serdecznika pospolitego. Na podstawie szczegółowych
obserwacji cech makroskopowych oraz mikroskopowych obserwowanych in vitro w kulturach
na standardowych podłożach, izolaty P. capitulum zakwalifikowano do sekcji Phoma a izolaty
P. septicidalis do sekcji Paraphoma.
Fig. 1. Pycnidia of Phoma capitulum (SEM x 250). Phot. M. Wróbel.
Fig. 2. Conidia of Phoma capitulum (SEM x 5100). Phot. M. Wróbel.
Fig. 3. Setose pycnidium of Phoma septicidalis
(SEM x 300). Phot. M. Wróbel.
Fig. 4. Conidia of Phoma septicidalis (SEM x
2600). Phot. M. Wróbel.
Fig. 5. Fragmentation of hyphae of Phoma septicidalis (SEM x 3000). Phot. M. Wróbel.