ArticlePDF Available

Phoma glomerata as a Mycoparasite of Powdery Mildew

American Society for Microbiology
Applied and Environmental Microbiology
Authors:
Raymond F Sullivan at Rutgers, The State University of New Jersey
Raymond F Sullivan
James F White at Rutgers, The State University of New Jersey
James F White
Download full-text PDF
Read full-text
Download citation

Abstract and Figures

Ampelomyces and Phoma species are frequently confused with each other. Isolates previously attributed to the genus Ampelomyces were shown to be Phomaisolates through studies of their morphology and life cycle and ribosomal DNA internal transcribed spacer region 1 sequence analysis.Phoma glomerata can colonize and suppress development of powdery mildew on oak and may have utility as a mycoparasitic agent.
Figures - uploaded by James F White
Author content
All figure content in this area was uploaded by James F White
Content may be subject to copyright.
Content uploaded by James F White
Author content
All content in this area was uploaded by James F White
Content may be subject to copyright.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY,
0099-2240/00/$04.00⫹0Jan. 2000, p. 425–427 Vol. 66, No. 1
Copyright © 2000, American Society for Microbiology. All Rights Reserved.
Phoma glomerata as a Mycoparasite of Powdery Mildew
RAYMOND F. SULLIVAN AND JAMES F. WHITE, JR.*
Department of Plant Pathology, Cook College, Rutgers University, New Brunswick, New Jersey 08901
Received 26 July 1999/Accepted 2 November 1999
Ampelomyces and Phoma species are frequently confused with each other. Isolates previously attributed to the
genus Ampelomyces were shown to be Phoma isolates through studies of their morphology and life cycle and
ribosomal DNA internal transcribed spacer region 1 sequence analysis. Phoma glomerata can colonize and
suppress development of powdery mildew on oak and may have utility as a mycoparasitic agent.
Powdery mildews are widespread plant pathogens that are
conspicuous by their white mycelia and powder-like conidia
(20). The fungus Ampelomyces quisqualis Ces. is the only fun-
gus that has been demonstrated to be generally effective as a
biocontrol agent of powdery mildew (4, 9, 16). Many morpho-
logically similar species may be confused with A. quisqualis
(10). To evaluate this possibility, we examined and identified
Ampelomyces-like fungi isolated from powdery mildew and
compared these cultures with isolates identified as Ampelomy-
ces in culture collections.
Isolation and growth. Leaves of sycamore trees (Platanus
occidentalis L.) bearing infections of powdery mildew (Mi-
crosphaera penicillata (Wallr.:Fr.) Le`v.) were located in South
River, New Jersey, in July 1998. Microscopic examination of
the leaves revealed two types of pycnidia: stipitate pycnidia,
typical of A. quisqualis, and sessile pycnidia, typical of the
genus Phoma (Fig. 1) (17). Both types of pycnidia were re-
moved from leaves with fine needles and placed on potato
dextrose agar (Difco, Inc., Detroit, Mich.) containing the an-
tibiotics gentamicin (40 mg/liter), streptomycin (40 mg/liter),
and penicillin (20 mg/liter) (PDA ⫹3). Two different fungi
were consistently recovered. The stipitate pycnidia developed
into slow-growing colonies whose characteristics corresponded
to those expected for A. quisqualis (5, 11). The sessile pycnidia
developed into rapidly growing colonies whose characteristics
corresponded to those of Phoma glomerata (Cda) Wollenw. (2,
19).
Agar plugs (6 mm in diameter) of mycelia cut from the
margins of rapidly growing colonies of both the South River
Ampelomyces and South River P. glomerata isolates were trans-
ferred to five plates each of PDA⫹3 and incubated at room
temperature (21 to 22°C) for 3 weeks to measure growth rates.
We measured an average growth of 8 ⫾1 mm/day for the P.
glomerata isolates and an average growth of 0.8 ⫾0.1 mm/day
for the Ampelomyces isolates. With age, cultures of P.
FIG. 1. (A) Stipitate pycnidium of A. quisqualis (arrow). (B) Section of sessile pycnidium of P. glomerata on oak leaf (arrow). Scale bar ⫽20 ␮m.
* Corresponding author. Mailing address: Department of Plant Pa-
thology, 386 Foran Hall, Cook College, Rutgers University, New
Brunswick, NJ 08901. Phone: (732) 932-9375, ext. 357. Fax: (732)
932-9377. E-mail: jwhite@aesop.rutgers.edu.
425
glomerata produced alternarioid dictyochlamydospores mea-
suring 41 ⫾7.5 ⫻12 ⫾1.4 ␮m.
Inoculation experiments. Koch’s postulates (1, 3) were used
to establish the pathogenicity of P. glomerata to powdery mil-
dew. A suspension of P. glomerata conidia from cultures grown
on PDA⫹3 was made in sterile water (⬃8⫻10
6
conidia/ml).
The conidial suspension was used to inoculate epiphyllous
mycelia of the powdery mildew Phyllactinia guttata (Wallr.:Fr.)
Le`v. on intact (left on the tree) leaves of oak (Quercus coccinea
Mu¨nch.) by moistening an approximately 15-mm
2
region on
the upper surface of the leaves. Controls were repeats of this
process with sterile water. Ten replicates of both the treatment
and control were made, and the sites of inoculation were
marked by placing white tape on the reverse of the leaves at the
inoculation sites. The leaves were monitored for 30 days. Dur-
ing this time, control leaves developed powdery mildew cleis-
tothecia while all leaves treated with P. glomerata conidia de-
veloped abundant pycnidia in and around the inoculation sites
but did not produce powdery mildew cleistothecia. None of the
control leaves showed development of P. glomerata pycnidia,
and cleistothecia developed normally. To fulfill Koch’s postu-
lates, pycnidia were removed from treated leaves with fine
needles and plated on PDA⫹3 medium to recover P.
glomerata. Colonies that developed were confirmed to be P.
glomerata by observation of dictyochlamydospores, pycnidia,
and subsequent sequence analysis.
Phylogenetic analysis. The nuclear ribosomal DNA internal
transcribed spacer region 1 (ITS1) from P. glomerata, several
Ampelomyces spp., and several Phoma spp. were sequenced.
The South River P. glomerata and A. quisqualis, as well as
American Type Culture Collection (ATCC) cultures of Ampe-
lomyces heraclei (Dejeva) Rudakov (ATCC 36804) and A. quis-
FIG. 2. Maximum likelihood phylogram based on ITS region sequences between the 18S and 5.8S ribosomal DNA (ITS1). Bootstrap confidence levels (percent)
of branches are shown. The scale bar is based on a total tree length of 204. Taxa included in the analysis, GenBank numbers (if known), and their sources are as follows:
LM,L. microscopica (LMU04234); PAV,P. avenaria (PAU77357); AQ1, A. quisqualis (AQU82451, DSM [Deutsche Sammlung von Mikrooganismen und Zellkulturen
GmbH, Braunschweig, Germany] 2223); AQ2, A. quisqualis (AF126818, South River); AQ3, A. quisqualis (AF126817, ATCC 200245); AQ4, A. quisqualis (AF035782);
AQ5, A. quisqualis (AQU82449, CBS [Centraalbureau voor Schimmelcultures, Baarn, The Netherlands] 130.79); AQ6, A. quisqualis (AF035783, Ecogen AQ10); AQ7,
A. quisqualis (AF035781, CBS 131.31); AQS,A. quercinus (AF035778, ATCC 36786); PG,P. glomerata (AF126816, South River); AHE,A. heraclei (AF126819, ATCC
36804); AHU,A. humuli (AF035779, ATCC 38616); PAM,P. americana Morgan-Jones et White (AF046016); PM,P. macrostoma Mont. (AF046020); PS,P. sorghina
(Sacc.) Boerema (AF046022); DL,D. lycopersici Klebahn (AF046015); and DB,D. bryoniae (Auersw.) Rehm (AF046014).
426 SULLIVAN AND WHITE APPL.ENVIRON.MICROBIOL.
qualis (ATCC 200245), were grown on PDA⫹3. DNA extrac-
tion, amplification, and sequencing were accomplished as
described previously (14).
Several additional ITS1 sequences identified as Ampelomy-
ces spp., including Ampelomyces humuli (Fautr.) Rudakov,
Ampelomyces quercinus (Syd.) Rudakov, Phaeosphaeria avena-
ria (Weber) Eriksson, and Leptosphaeria microscopica P. Karst.
were obtained from GenBank (Fig. 2).
The SeqLab interface for the Wisconsin Package Version 9.1
(Genetics Computer Group, Madison, Wis.) was used to gen-
erate alignments and make manual adjustments. PAUP ver-
sion 4.0b2 for Macintosh (17) was used for phylogenetic anal-
ysis. Heuristic searches were performed by using maximum
parsimony (14). Bootstrapping, using the same criteria with
400 replicates, was performed to determine the confidence
levels of the inferred phylogenies. Trees found by maximum
parsimony were subjected to heuristic searches by using max-
imum likelihood criteria by the Hasegawa-Kishino-Yano
model (6) to find the most likely tree (See Treebase [http:
//herbaria.harvard.edu/treebase] submission no. SN145 for
alignment and tree construction details).
Maximum parsimony analysis resulted in ten trees. Maxi-
mum likelihood analysis of these trees resulted in one tree
(⫺lnL⫽1200, tree length ⫽204, consistency index ⫽0.78,
homoplasy index ⫽0.22, retention index ⫽0.79). The South
River P. glomerata is identical to A. heraclei and A. humuli, and
they group together with A. quercinus in the Didymella/Phoma
clade (Fig. 2). Our South River A. quisqualis isolate grouped in
the Ampelomyces clade with Ecogen’s A. quisqualis AQ10.
There was strong bootstrap support for the Ampelomyces
(90%) and Phoma (100%) clades.
Distinguishing Phoma from Ampelomyces. Stipitate pycnidia
developing into slow-growing colonies characterize A. quisqua-
lis (5, 11). Sessile pycnidia developing into rapidly growing
colonies characterize P. glomerata (2, 19). The cultures identi-
fied as A. heraclei,A. humuli, and A. quercinus are typical
representatives of their species.
The process of pycnidium formation in association with the
powdery mildew is also different between the two genera. Am-
pelomyces spp. infect conidiogenous cells of powdery mildew,
internally colonizing and forming pycnidia within the conidio-
phore; the pycnidia appear stipitate (Fig. 1). Phoma sp. does
not appear to internally infect conidiogenous cells, and pyc-
nidia are formed directly on the leaf surface; they are sessile
(Fig. 1). While many species of Phoma are plant pathogens
(17), P. glomerata is not. However, Phoma can grow saprophyt-
ically in tissues of plants and is known to be a secondary
invader of diseased tissues, perhaps feeding on fungal sapro-
phytes or pathogens of diseased tissues (12, 17, 19). P.
glomerata has been isolated from species of the powdery mil-
dew genus Microsphaera in the United States (this study) and
Russia (as A. quercinus) and from species of the genus Spha-
erotheca (as A. humuli) in Russia (15). It also has been isolated
from the downy mildew of grapes (Plasmopara viticola (Berk.
et Curt.) Berl. et De Toni) in Russia (as A. heraclei) (15). It is
apparent that P. glomerata has a widespread distribution.
Potential new mycoparasitic agent. Currently a single strain
of fungus, A. quisqualis AQ10 Biofungicide, is in commercial
use for biocontrol of powdery mildew on grapes and other
crops (7). This strain grouped within the divergent Ampelomy-
ces clade and appears to correctly represent a species of that
genus. A few reports have identified Phoma species that are
antagonistic to fungal plant pathogens. A Phoma sp. (P66A)
significantly reduced conidial germination of an apple scab
(Venturia inaequalis (Cooke) Wint.) (13), and Phoma etheridgei
Hutch. & Hirat. produced antifungal compounds inhibitory to
the tree pathogen Phellinus tremulae (Bond) Bond et Borisov
(8).
Our results suggest that P. glomerata is frequently misiden-
tified as A. quisqualis or other species of Ampelomyces. Addi-
tionally, P. glomerata often may inhabit powdery mildew infec-
tions and may be an important component of a hyperparasitic
guild of fungi that naturally infect powdery mildews. Further
study is warranted to evaluate the effectiveness of P. glomerata
in the hyperparasitic control of fungal plant pathogens.
Nucleotide sequence accession numbers. The following se-
quences were deposited in GenBank: A. quisqualis ATCC
200245 and South River, P. glomerata South River, A. heraclei
ATCC 36804. Their accession numbers are listed in the legend
for Fig. 2.
REFERENCES
1. Agrios, G. N. 1988. Plant Pathology, 3rd ed. Academic Press, Inc., San Diego,
Calif.
2. Boerema, G. H., M. M. J. Dorenbosch, and H. A. van Kesteren. 1965.
Remarks on species of Phoma referred to Peyronellaea. Persoonia 4:47–68.
3. Brock, T. D. 1988. Robert Koch, a life in medicine and bacteriology. Science
Tech Publishers, Madison, Wis.
4. Falk, S. P., D. M. Gadoury, P. Cortesi, R. C. Pearson, and R. C. Seem. 1995.
Partial control of grape powdery mildew by the mycoparasite Ampelomyces
quisqualis. Plant Dis. 79:483–490.
5. Galper, S., A. Sztejnberg, and N. Lisker. 1985. Scanning electron microscopy
of the ontogeny of Ampelomyces quisqualis pycnidia. Can. J. Microbiol.
31:961–964.
6. Hasegawa, M., H. Kishino, and T. Yano. 1985. Dating of the human-ape
splitting by a molecular clock of mitochondrial DNA. J. Mol. Evol. 21:160–
174.
7. Hofstein, R., and B. Fridlender. 1994. Development of production, formu-
lation and delivery systems, p. 1273–1280. In Brighton Crop Protection
Conference—pests and diseases, vol. 3. British Crop Protection Council,
Farnham, United Kingdom.
8. Hutchinson, L. J., P. Chakravarty, L. M. Kawchuck, and Y. Hirasuka. 1994.
Phoma etheridgei sp. nov. from black galls and cankers of trembling aspen
(Populus tremuloides) and its potential role as a bioprotectant against the
aspen decay pathogen Phellinus tremulae. Can. J. Bot. 72:1424–1431.
9. Jarvis, W. R., and K. Slingsby. 1977. The control of powdery mildew of
greenhouse cucumber by water spray and Ampelomyces quisqualis. Plant Dis.
Rep. 61:728–730.
10. Kiss, L. 1997. Genetic diversity in Ampelomyces isolates, hyperparasites of
powdery mildew fungi, inferred from RFLP analysis of the rDNA ITS re-
gion. Mycol. Res. 101:1073–1080.
11. Kiss, L., and K. K. Nakasone. 1998. Ribosomal DNA internal transcribed
spacer sequences do not support the species status of Ampelomyces quisqua-
lis, a hyperparasite of powdery mildew fungi. Curr. Genet. 33:362–367.
12. Morgan-Jones, G. 1967. Phoma glomerata.In CMI descriptions of patho-
genic fungi and bacteria no. 134. Commonwealth Mycological Institute, Kew,
United Kingdom.
13. Ouimet, A., O. Carisse, and P. Neumann. 1997. Environmental and nutri-
tional factors affecting the in vitro inhibition of the vegetative growth of
Venturia inaequalis by five antagonistic fungi. Can. J. Bot. 75:632–639.
14. Reddy, P. V., R. Patel, and J. F. White, Jr. 1998. Phylogenetic and develop-
mental evidence supporting reclassification of cruciferous pathogens Phoma
lingham and P. wasabiae in genus Plenodomus. Can. J. Bot. 76:1916–1922.
15. Rudakov, O. L. 1979. Fungi of the genus Ampelomyces Ces. Ex. Schlect.
Mikologiya i Fitopatologiya 13:104–110.
16. Sundheim, L., and A. Tronsmo. 1988. Hyperparasites in biological control, p.
53–70. In K. G. Mukerji and K. L. Garg (ed.), Biocontrol of plant diseases.
CRC Press, Boca Raton, Fla.
17. Sutton, B. C. 1980. The coelomycetes. Commonwealth Mycological Institute,
Kew, United Kingdom.
18. Swofford, D. L. 1999. PAUP*. Phylogenetic Analysis Using Parsimony (*and
other methods). Version 4. Sinauer Associates, Sunderland, Mass.
19. White, J. F., Jr., and G. Morgan-Jones. 1987. Studies in the genus Phoma.
VII. Concerning Phoma glomerata. Mycotaxon 28:437–445.
20. Yarwood, C. E. 1978. History and taxonomy of powdery mildews. In D. M.
Spencer (ed.), The powdery mildews. Academic Press, Inc., London, United
Kingdom.
VOL. 66, 2000 P. GLOMERATA AS A MYCOPARASITE OF POWDERY MILDEW 427

Supplementary resources (4)

Phoma glomerata 18S ribosomal RNA gene, partial sequence; internal transcribed spacer 1, 5.8S ribosomal RNA and internal transcribed spacer 2, complete sequence; and 26S ribosomal RNA gene, partial sequence
Nucleotide Sequence
February 1999
Raymond F Sullivan · James F White
Ampelomyces quisqualis 18S ribosomal RNA gene, partial sequence; internal transcribed spacer 1, 5.8S ribosomal RNA and internal transcribed spacer 2, complete sequence; and 26S ribosomal RNA gene, partial sequence
Nucleotide Sequence
February 1999
Raymond F Sullivan · James F White
Ampelomyces quisqualis 18S ribosomal RNA gene, partial sequence; internal transcribed spacer 1, 5.8S ribosomal RNA and internal transcribed spacer 2, complete sequence; and 26S ribosomal RNA gene, partial sequence
Nucleotide Sequence
February 1999
Raymond F Sullivan · James F White
Phoma glomerata 18S ribosomal RNA gene, partial sequence; internal transcribed spacer 1, 5.8S ribosomal RNA and internal transcribed spacer 2, complete sequence; and 26S ribosomal RNA gene, partial sequence
Nucleotide Sequence
February 1999
Raymond F Sullivan · James F White
... Undoubtedly, population genetic studies in Ampelomyces are difficult to carry out. For example, some nucleotide sequences deposited in public databases under the name of Ampelomyces are not related to the mycoparasites by comparing their phylogeny and growth rates in culture [30,31]. In addition, most phylogenetic studies have been based on the ITS region [28][29][30][32][33][34] and other molecular markers may be required for species identification due to the high genetic divergence of ITS sequences from some Ampelomyces lineages that can reach up to 15% [24,30]. ...
... Group 1 contains two sequences of fungi identified as Ampelomyces humuli, which was derived from plant tissues of Picea abies decayed root [46] and from Zea mays [40]. Group 1 also contains three sequences from fungi known to form a different phylogenetic group from the 'true' species of the genus Ampelomyces [30,31] and are referred to as A. humuli (GenBank sequence identifier (GI) AF035779), Ampelomyces quercinus (GI: AF035778) and Ampelomyces sp. (GI: U82452). ...
... derived from creosote-treated crosstie waste [38] and air samples [47], Table 3 in S1 File. Finally, the outgroup is formed by ITS sequences belonging to four Didymella species [31,[48][49][50] and one Phoma species [51], Table 4 in S1 File. ...
Ampelomyces mycoparasites of powdery mildews – A review
Article
Full-text available
  • May 2023
This review paper highlights the significant research conducted on fungi belonging to the genus Ampelomyces. Phylogeny based on both ITS and actin sequences has grouped Ampelomyces into different lineages. However, the ITS2 spacer, one constituent of the ITS region, together with their secondary structures (S2s), showed that these lineages are represented by different S2s; also, evidence of pseudogene formation in nuclear ribosomal genes of two isolates was reported, and S2s in Ampelomyces mycoparasites are different from those in Phoma-like fungi. Ampelomyces taxonomy is unresolved and future multi-locus analysis will assist in delimiting species. Members of the genus Ampelomyces are among the first mycoparasites used to control powdery mildew fungi as they can efficiently eliminate mycelial growth and reduce the overwintering inoculum of their mycohosts. In addition, Ampelomyces isolates were found to be resistant to some fungicides and insecticides, e.g. pyrazophos, an attractive feature for their selection as biocontrol agents. Transcriptome analyses have revealed that expression of the genes that encode proteins putatively associated with virulence and plant immune responses were enhanced during host recognition, while genes encoding proteins linked to antibiotic resistance were predicted within the Ampelomyces genome. Proteomic studies are needed to confirm whether these proteins function in virulence and can therefore be used for biocontrol purposes or as bacterial antibiotic-resistant proteins, and which of these may trigger plant immune responses to facilitate plant protection. We encourage the continuation of these studies to benefit crop protection research.
View
... Didymella glomerata is associated with stem canker of peach, damping off, and root necrosis in fennel and stem rot of coriander [49][50][51][52]. It has also been reported to be a mycoparasite of powdery mildew [85]. Didymella glomerata as P. glomerata has been recorded as an endophytic fungus from Korean pine (Pinus koraiensis) leaves [86]. ...
Microfungi Associated with Peach Branch Diseases in China
Article
Full-text available
  • Mar 2024
  • J. Fungi
Peach (Prunus persica L.) is one of the most important and oldest stone fruits grown in China. Even though P. persica is one of the most commonly grown stone fruits in China, little is known about the biodiversity of microfungi associated with peach branch diseases. In the present study, samples were collected from a wide range of peach growing areas in China, and fungal pathogens associated with peach branch diseases were isolated. In total, 85 isolates were obtained and further classified into nine genera and 10 species. Most of the isolates belonged to Botryosphaeriaceae (46), including Botryosphaeria, Diplodia, Neofusicoccum, Phaeobotryon, and Lasiodiplodia species; Ascochyta, Didymella, and Nothophoma species representing Didymellaceae were also identified. Herein, we introduce Ascochyta prunus and Lasiodiplodia pruni as novel species. In addition, we report the first records of Nothophoma pruni, Neofusicoccum occulatum, and Phaeobotryon rhois on peach worldwide, and Didymella glomerata, Nothophoma quercina, and Phaeoacremonium scolyti are the first records from China. This research is the first comprehensive investigation to explore the microfungi associated with peach branch disease in China. Future studies are necessary to understand the pathogenicity and disease epidemiology of these identified species.
View
... Derx (Urquhart et al., 1994), Sporothrix flocculosa Traquair Shaw & Jarvis (Elad, 1995), Phoma glomerata (Corda) Wollenw. & Hochapwel (Sullivan & White, 2000), Tilletiopsis minor and Trichothecium roseum (Gams et al., 2004), or Cladosporium uredinicola Speg (Dugan & Glawe, 2006), were found over the period of the study. e latter, which occurs mainly on various developmental stages of Puccinales fungi, colonizes also the representatives of Erysiphales: Phyllactinia angulata (E. S. Salomon) S. Blumer, and Phyllactinia guttata (Wallr.) ...
Fungicolous fungi on microscopic fungi parasitic to the vegetation of the urban environment
Article
Full-text available
  • Dec 2023
The research aimed to study the extent of fungicolous fungi prevalence on the thallus of fungi parasitic to the plants of the urban environment and to assess the species diversity of these microorganisms, with particular attention paid to the phenomenon of hyperparasitism. The research material consisted of herbaceous plants, trees, and shrubs showing signs of infestation by fungi, planted as park plants, along communication arteries, for hedges or ornamental plants, collected in larger cities of north-eastern Poland. Macroscopic and microscopic analysis revealed the presence of 12 different species of fungicolous fungi. The greatest diversity was found on the parasite of Alcea rosea , i.e., Puccinia malvaceraum , on which four fungal species were recorded. Four species of hyperparasites were identified: Ampelomyces quisqualis on the thallus of 19 Erysiphales species , Cladosporium uredinicola on the thallus of 5 species of the Pucciniales order, Clonostachys epichloë on Epichloë typhina , and Sphaerellopsis filum on the thallus of 11 representatives of Pucciniales. The study was also the first to record the presence of superparasites: Ampelomyces quisqualis on four Erysiphales species and Sphaerellopsis filum on three Pucciniales species. It is difficult to determine the relationships established by the other identified fungicolous fungi due to the lack of literature data. Nevertheless, the study demonstrated the presence of, among others, Stemphylium sarciniforme structures inside Erysiphe palczewskii appendages and the absence of ascospores inside the fruiting bodies indicative of the invasive nature of this relationship. However, confirmation of these findings requires further detailed microscopic and molecular analyses.
View
... Antibiotics have also been made using some Penicillium species (Kharwa et al., 2010). The search for new biologically active metabolites from endophytes have been studied extensively, and more than 280 substances with antimicrobial, anticancer, antiviral, antioxidant, antiinflammatory, antiparasitic, immunosuppressant, anti-obesity, antifibrotic, neuroprotective, insecticidal, and biocontrol activities have been identified (Toghueo and Boyom, 2020;Sullivan and White, 2000). In addition, the fungus Phoma has been shown to be an efficient biocontrol agent for powdery mildew (Zhang et al., 2012). ...
Efficacy of endophytic fungi isolated from Azadirachta indica roots against Alternaria causing early blight of tomato
Article
Full-text available
  • Dec 2023
Many medicinal plants are reported to host a myriad of beneficial endophytic microbes. Among the well-known medicinal plants is Azadirachta indica (Neem; Family Meliaceae), which has gained worldwide importance due to its extensive array of therapeutic and insecticidal qualities. The use of A. indica extracts in the treatment of plant pathogens has been the subject of extensive investigation, but its endophytic microbes as potential biocontrol agents have received very little attention. In this study, the efficacy of endophytic fungi isolated from A. indica roots against Alternaria, which causes tomato early blight, was examined. Isolation and characterization of Alternaria species and endophytic fungi were done in the laboratory using standard procedures. An in-vitro assay of the endophytic fungi isolates against Alternaria was conducted in a complete randomized design in order to determine the percentage zone of inhibition. The colonies of Alternaria isolates were fast-growing, black to grayish-brown, and suede-like. The conidial length from different isolates was statistically significant (p ˂ 0.05) and ranged from 15 μm to 46 μm. The conidial widths were not statistically significant (p > 0.05) and ranged from 8 μm to 15 μm, while the conidial area ranged from 120 μm to 690 μm. A total of seven species of endophytes were isolated from the root of Azadirachta indica: Phoma, Actinomycetes, Chaetomium, Trichoderma, Verticillium, Penicillium, and Fusarium. There was a significant difference in the zones of inhibition (p ˂ 0.05), which ranged from 0.0 mm (Actinomycetes) to 3.44 mm (Trichoderma). These isolates could be used to create brand-new organic antifungal substances that are efficient against a variety of plant fungal pathogens.
View
... Phoma is considered a saprophyte, and a weak pathogen (Sutton 1980;Kumar et al. 2015), mostly causing leaf and stem spots (Lin et al. 2014). Phoma glomerata has also been reported as a mycoparasite that suppress powdery mildew in sycamore trees (Sullivan and White 2000). There are other reports indicating that some Phoma species can have antagonistic activity against some plant pathogens. ...
Interactions between fungal endophytes and pathogens isolated from the invasive plant kudzu (Pueraria montana var. lobata)
Article
  • Feb 2023
In this study, we examined the in vitro interactions between fungal endophytes and pathogens isolated from the invasive plant kudzu (Pueraria montana var. lobata) and test if endo-phytes might facilitate pathogen growth. This represents a required initial step towards the development of candidate fungal inocula that can aid in the suppression of kudzu. While most tested endophyte-pathogen assays suggest antagonism and/or competitive exclusion, we identified several pathogen/endophyte combinations that suggest pathogen facilitation. Additional work is needed to test if these may have in planta effects on phytopathogenicity. The present study accentuates on the potential of fungal endophytes as an effective ecological approach to manage invasive plants via pathogens facilitation.
View
... Анализ последовательностей производился в системе NCBI BLAST с использованием депозитов, относящихся к видам подотряда Pleosporineae (рис. [5][6][7][8]. ...
Structural and functional organisation of the phytopathogenic fungi Phoma sp.1 mitochondrial genome
Article
Full-text available
  • Nov 2022
The article presents the results of the mitochondrial DNA (30 837 n. r.) sequencing of the phytopathogenic fungi Phoma sp.1 – causative agent of Phoma blight of the pine and spruce plants cultivated in the forest nurseries. Annotation of the Phoma sp.1 mitochondrion showed 43 coding loci. Potential open reading frames (orf89, orf87, orf76 and orf108) and gene introns (cox3, nad1) are described. A comparative single genes analysis in the NCBI GenBank database showed, that Phoma sp.1 belongs to the Didymella spp., which can have Phoma anamorph. It has been shown that mitohondrial genes can be used as DNA markers for the diagnosis of Phoma and phoma-like fungi. Analysis of the mitochondrial synthenia of Phoma sp.1 and a related species (including phoma-like fungi), revealed significant structural rearrangements in mtDNA during phylogenesis.
View
... The soil-borne ascomycetous fungus Phoma glomerata (current name: Didymella glomerata) has been described as a plant pathogen [92,93] as well as a potential biocontrol agent [94,95]. The strain P. glomerata no. ...
Control Strategies of Clubroot Disease Caused by Plasmodiophora brassicae
Article
Full-text available
  • Mar 2022
The clubroot disease caused by the soil-borne pathogen Plasmodiophora brassicae is one of the most important diseases of cruciferous crops worldwide. As with many plant pathogens, the spread is closely related to the cultivation of suitable host plants. In addition, temperature and water availability are crucial determinants for the occurrence and reproduction of clubroot disease. Current global changes are contributing to the widespread incidence of clubroot disease. On the one hand, global trade and high prices are leading to an increase in the cultivation of the host plant rapeseed worldwide. On the other hand, climate change is improving the living conditions of the pathogen P. brassicae in temperate climates and leading to its increased occurrence. Well-known ways to control efficiently this disease include arable farming strategies: growing host plants in wide crop rotations, liming the contaminated soils, and using resistant host plants. Since chemical control of the clubroot disease is not possible or not ecologically compatible, more and more alternative control options are being investigated. In this review, we address the challenges for its control, with a focus on biological control options.
View
The Identity, Virulence, and Antifungal Effects of the Didymellacesous Fungi Associated with the Rapeseed Blackleg Pathogen Leptosphaeria biglobosa
Article
Full-text available
  • Dec 2023
  • J. Fungi
Eight fungal strains (P1 to P8) were isolated from rapeseed stems (Brassica napus) infected with the blackleg pathogen Leptosphaeria biglobosa (Lb). They formed pycnidia with similar morphology to those of Lb, and thus were considered as Lb relatives (LbRs). The species-level identification of these strains was performed. Their virulence on rapeseed and efficacy in the suppression of Lb infection were determined, and the biocontrol potential and biocontrol mechanisms of strain P2 were investigated. The results showed that the LbRs belong to two teleomorphic genera in the family Didymellaceae, Didymella for P1 to P7 and Boeremia for P8. Pathogenicity tests on rapeseed cotyledons and stems indicated the LbRs were weakly virulent compared to L. biglobosa. Co-inoculation assays on rapeseed cotyledons demonstrated that P1 to P7 (especially P1 to P4) had a suppressive effect on Lb infection, whereas P8 had a marginal effect on infection by L. biglobosa. Moreover, D. macrostoma P2 displayed a more aggressive behavior than L. biglobosa in the endophytic colonization of healthy rapeseed cotyledons. Cultures of P2 in potato dextrose broth (PDB) and pycnidiospore mucilages exuded from P2 pycnidia showed antifungal activity to L. biglobosa. Further leaf assays revealed that antifungal metabolites (AM) of strain P2 from PDB cultures effectively suppressed infection by L. biglobosa, Botrytis cinerea (gray mold), and Sclerotinia sclerotiorum (white mold). An antifungal metabolite, namely penicillither, was purified and identified from PDB cultures and detected in pycnidiospore mucilages of strain P2. This study suggests that the LbRs are a repertoire for screening biocontrol agents (BCAs) against rapeseed diseases, and D. macrostoma P2 is a multi-functional BCA, a penicillither producer, and an endophyte.
View
Identification of Didymellaceae fungi associated with different disease symptoms in some medicinal plants of Khuzestan Province, Iran
Article
Full-text available
  • Jan 2023
Bitter apple (Citrullus colocynthis), camelthorn (Alhagi sp.), cordia (Cordia myxa), dill (Anethum graveolens), eucalyptus (Eucalyptus sp.), licorice (Glycyrrhiza glabra), plantain (Plantago sp.), and rosemary (Rosmarinus officinalis) are medicinal plants distributed in different parts of Khuzestan province. These plants could be host to many pathogenic and non-pathogenic fungi. In this study, 30 samples from medicinal plants showing leaf spot, stem canker and stem necrosis were collected during 2019-2020, and in which 23 isolates of six species in the family Didymellaceae were identified. Molphological characteristics were studied on potato – dextrose - agar (PDA). For molecular study, partial regions of tub2 gene were amplified using appropriate primers and sequenced. Based on molecular phylogeny in combination with morphology, the isolates were identified as follow: Allophoma labilis, Didymella glomerata, Epicoccum italicum, Neodidymelliopsis farokhinejad, Nothophoma raii and Xenodidymella glycyrrhizicola. In our knowledge, this is the first report of above species on surveyed hosts and first record of both E. italicum and N. raii for mycobiota of Iran.
View
Leaf blight caused by Didymella glomerata on blackberry in Turkey
Article
  • Oct 2022
The cultivation of blackberries has recently increased in Turkey, despite the fact that wild blackberry types have grown almost everywhere in the country. During the summer of 2011, leaf blight symptoms were observed in a blackberry vineyard in Karlısu, as well as on wild blackberry plants in Altınözü, Hatay province, Turkey. Based on morphology, fungal isolates obtained from these blighted leaf margins shared similar morphological characteristics and were tentatively identified as Didymella glomerata. To confirm the morphologic identification, the nucleotide sequences of a representative isolate’s ITS, LSU, and tub2 regions of DNA were used. The sequences of three regions were 99–100% identical to D. glomerata isolate sequences in GenBank. Healthy blackberry suckers of the thornless blackberry cultivars ‘Triple Crown’ and ‘Chester’ grown in pots were inoculated with spore suspension on foliar parts under greenhouse conditions for pathogenicity testing. D. glomerata was extremely virulent, causing severe leaf blight in both blackberry cultivars. D. glomerata was constantly isolated from inoculated plants’ leaf lesions. This is the first report of D. glomerata infection of blackberry, a novel host for this pathogen in Turkey and around the world. More research into the biology and management of the disease is required.
View
Partial Control of Grape Powdery Mildew by the Mycoparasite Ampelomyces quisqualis
Article
Full-text available
  • Jan 1995
  • PLANT DIS
Ampelomyces quisqualis normally infects senescent colonies of Uncinula necator in late summer. Our objective was to introduce the mycoparasite at the start of an epidemic, and thereby reduce the rate of disease increase. Prior to establishing field trials, isolates of A. quisqualis were evaluated for pathogenicity, virulence, and host range in greenhouse and laboratory assays. Infection of powdery mildew colonies only occurred when plants were kept wet and resulted in sporulation of A. quisqualis within 10 days. Two isolates of A. quisqualis (G5 and G273) were evaluated for pathogenicity and virulence against 18 monoconidial isolates of U. necator on grape seedlings and showed little evidence of pathogenic specialization. Three isolates (G273, SF419, and SF423) were equally pathogenic to Sphaerotheca fuliginea on cucurbit, S. macularis on strawberry, and U. necator on grape seedlings. All A. quisqualis isolates appear to have a broad host range and cause significant damage to powdery mildew colonies. Pycnidia of A. quisqualis G273 were produced on cotton wicks saturated with malt extract agar or wheat bran malt extract agar. Wicks were suspended above grapevines of Vitis vinifera «Riesling» and Vitis interspecific hybrid Aurore. Conidia were dispersed during rain to infect powdery mildew colonies while leaf surfaces were wet. Conidia were released for 3 months in 1990 from a single deployment of wicks. Higher numbers of conidia were released during the entire growing season in 1992 and 1993 due to replenishment of colonized wicks at monthly intervals. Wicks released conidia for 1 to 2 months in 1992 and 1993 before becoming depleted. Powdery mildew development was reduced on Riesling vines in 1990 following deployment of colonized wicks at 15 cm of shoot growth. Disease severity but not incidence was reduced on Aurore vines in 1992 under A. quisqualis-colonized wicks. High rainfall in 1992 provided ample opportunities for dispersal of inoculum of the mycoparasite and the wet conditions were conducive to parasitism. Disease development was late and much reduced in 1993, which was a drier season than 1992. Consequently, no differences were observed in A. quisqualis-treated and untreated plots in the same vineyard that year
View
View
View
View
View
View
View
Remarks on Species of Phoma Referred to Peyronellaea, V
Article
  • Jan 1977
A review is given of the synonymy, characteristics and differentiating diagnostic criteria of Phoma glomerata, P. jolyana, P. jolyana var. circinata (Kuznetz.) comb. nov., P. , pomorum and P. sorghina. A synopsis of the taxonomic position of all the Peyronellaeas mentioned in literature is added.
View
Scanning electron microscopy of the ontogeny of Ampelomyces quisqualis pycnidia
Article
  • Oct 1985
  • CAN J MICROBIOL
Observations on Ampelomyces quisqualis disclosed that the pycnidium may originate either from one cell of a single pycnidiospore, or from one hyphal cell. In the first case the pycnidiospore becomes two celled and swollen and a profuse germination of one of the two swollen spore cells can be observed. Later, the short hyphae branches, interweave, and anastomose to form a compact network around the mother spore, the pycnidium primordium. Similarly, we observed profuse branching in a single hyphal cell. The newly formed branches interweave and anastomose to form a compact network which gives rise to the pycnidium primordium. Hyphal rings were also observed throughout this study, but no pycnidia arose from these structures. During the vegetative growth of the fungus, hyphal anastomosis seems to be a frequent pattern. It seems that the pycnidial ontogeny of A. quisqualis does not conform to any known developmental type.
View
View