Species of the anamorph genus Phoma are commonly isolated from a wide range of ecological niches. They are notoriously difficult to identify due to the paucity of morphological features and the ...plasticity of these when cultivated on agar media. Species linked to Phoma section Peyronellaea are typified by the production of dictyochlamydospores and thus have additional characters to use in taxon delineation. However, the taxonomy of this section is still not fully understood. Furthermore the production of such chlamydospores also is known in some other sections of Phoma. DNA sequences were generated from three loci, namely ITS, actin, and β-tubulin, to clarify the phylogeny of Phoma taxa that produce dictyochlamydospores. Results were unable to support section Peyronellaea as a taxonomic entity. Dictyochlamydospore formation appears to be a feature that developed, or was lost, many times during the evolution of Phoma. Furthermore, based on the multigene analyses, five new Phoma species could be delineated while a further five required taxonomic revision to be consistent with the genetic variation observed.
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BFBNIB, GIS, IJS, KISLJ, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
The preparation of 2,4-diaza-1,3,5-pentanetrione compounds were described. The fungicidal effects of these compounds on the mycelial growth of the isolate, Phoma eupyrena were carried out by in vitro ...experiment. The results show that the response to treatment depended not only on the concentration of the compounds used and duration of inoculation but also on the chemical constitution. All the compounds tested were effective at concentrations greater than serial dilution 10 super(-2). At lower concentrations, they were not too effective. The compounds were very active against P. eupyrena.
The phoma-like dilemma Hou, L.W.; Groenewald, J.Z.; Pfenning, L.H. ...
Studies in mycology,
06/2020, Volume:
96, Issue:
1
Journal Article
Peer reviewed
Open access
Species of Didymellaceae have a cosmopolitan distribution and are geographically widespread, occurring in diverse ecosystems. The family includes several important plant pathogenic fungi associated ...with fruit, leaf, stem and root diseases on a wide variety of hosts, as well as endophytic, saprobic and clinically relevant species. The Didymellaceae was recently revised based on morphological and phylogenetic analyses of ex-type strains subjected to DNA sequencing of partial gene data of the LSU, ITS, rpb2 and tub2 loci. Several poly- and paraphyletic genera, including Ascochyta, Didymella and Phoma were redefined, along with the introduction of new genera. In the present study, a global collection of 1 124 Didymellaceae strains from 92 countries, 121 plant families and 55 other substrates, including air, coral, human tissues, house dust, fungi, insects, soil, and water were examined via multi-locus phylogenetic analyses and detailed morphological comparisons, representing the broadest sampling of Didymellaceae to date. Among these, 97 isolates representing seven new genera, 40 new species and 21 new combinations were newly introduced in Didymellaceae. In addition, six epitypes and six neotypes were designated to stabilise the taxonomy and use of older names. A robust, multi-locus reference phylogenetic tree of Didymellaceae was generated. In addition, rpb2 was revealed as the most effective locus for the identification of Didymellaceae at species level, and is proposed as a secondary DNA marker for the family.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In our ongoing search for new bioactive fungal metabolites, four previously undescribed oxazole carboxylic acid derivatives (
-
) for which we proposed the trivial names macrooxazoles A-D together ...with two known tetramic acids (
-
) were isolated from the plant pathogenic fungus
. Their structures were elucidated based on high-resolution mass spectrometry (HR-MS) and nuclear magnetic resonance (NMR) spectroscopy. The hitherto unclear structure of macrocidin Z (
) was also confirmed by its first total synthesis. The isolated compounds were evaluated for their antimicrobial activities against a panel of bacteria and fungi. Cytotoxic and anti-biofilm activities of the isolates are also reported herein. The new compound
exhibited weak-to-moderate antimicrobial activity as well as the known macrocidins
and
. Only the mixture of compounds
and
(ratio 1:2) showed weak cytotoxic activity against the tested cancer cell lines with an IC
of 23 µg/mL. Moreover, the new compounds
and
, as well as the known compounds
and
, interfered with the biofilm formation of
, inhibiting 65%, 75%, 79%, and 76% of biofilm at 250 µg/mL, respectively. Compounds
and
also exhibited moderate activity against
preformed biofilm with the highest inhibition percentage of 75% and 73% at 250 µg/mL, respectively.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Aims
One of the major limitations to the production of alfalfa (Medicago sativa) is the fungus Phoma medicaginis, which infects alfalfa and causes leaf spots. This study aims to understand alfalfa’s ...response to P. medicaginis infection, the colonization of arbuscular mycorrhizal fungus (AMF) and the effect of AMF on plant–pathogen interactions.
Methods and Results
Transcriptome analysis (RNA‐seq) was used to identify differentially expressed genes (DEGs) in alfalfa infected by P. medicaginis and colonized by AMF Rhizophagus intraradices. AMF ameliorated the effects of P. medicaginis infection on alfalfa by reducing leaf spot incidence and disease index by 39·48 and 56·18% respectively. Inoculation with pathogen and AMF induced the activity of defence pathways, including peroxidase (POD), polyphenol oxidase activities and jasmonic acid (JA), salicylic acid concentration. Plants showed differential expression of P. medicaginis resistance‐related genes, including genes belonging to pathogenesis‐related (PR) proteins, chitinase activity, flavonoid biosynthesis, phenylpropanoid biosynthesis, glutathione metabolism, phenylalanine metabolism and photosynthesis. Inoculation with AMF led to changes in the expression of genes involved in PR proteins, chitinase activity, phenylalanine metabolism and photosynthesis.
Conclusion
The physiological and transcriptional changes caused by P. medicaginis infection in non‐mycorrhizal and mycorrhizal alfalfa provides crucial information for understanding AMF’s association with pathogenic systems.
Significance and Impact of the Study
This study showed that AMF alleviated alfalfa leaf spots demonstrating that AMF can serve as a biocontrol strategy for alfalfa disease management.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The aim of our study was to examine the different concentrations of AuNPs as a new antimicrobial substance to control the pathogenic activity. The extracellular synthesis of AuNPs performed by using
...sp. as an endophytic fungus. Endophytic fungus was isolated from vascular tissue of peach trees (
) from Baft, located in Kerman province, Iran. The UltraViolet-Visible Spectroscopy (UV-Vis spectroscopy) and Fourier transform infrared spectroscopy provided the absorbance peak at 526 nm, while the X-ray diffraction and transmission electron microscopy images released the formation of spherical AuNPs with sizes in the range of 10-100 nm. The findings of inhibition zone test of Au nanoparticles (AuNPs) showed a desirable antifungal and antibacterial activity against phytopathogens including
AG1-IA (AG1-IA has been identified as the dominant anastomosis group) and
pv.
. The highest inhibition level against sclerotia formation was 93% for AuNPs at a concentration of 80 μg/mL. Application of endophytic fungus biomass for synthesis of AuNPs is relatively inexpensive, single step and environmentally friendly. In vitro study of the antifungal activity of AuNPs at concentrations of 10, 20, 40 and 80 μg/mL was conducted against rice fungal pathogen
to reduce sclerotia formation. The experimental data revealed that the Inhibition rate (RH) for sclerotia formation was (15, 33, 74 and 93%), respectively, for their corresponding AuNPs concentrations (10, 20, 40 and 80 μg/mL). Our findings obviously indicated that the RH strongly depend on AuNPs rates, and enhance upon an increase in AuNPs rates. The application of endophytic fungi biomass for green synthesis is our future goal.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Development of a plant disease like Phoma blight (Phoma sojicola) of soybean Glycine max (L.) Merr. in time and space is a variable, largely depending on environmental factors like temperature, ...precipitation and humidity. Considering importance of this disease, understanding its dynamics via mathematical and statistical models will help in disease forecasting and prevention of yield losses. To serve this objective, present study on epidemiology of Phoma leaf blight of soybean was carried out under natural epiphytotic conditions on 2 soybean cultivars (Shalimar soybean 1 and Kashmir local) at research farm of Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu and Kashmir during rainy (kharif) season 2019 and 2020. Weather factors significantly influenced disease development irrespective of crop cultivar as revealed by correlation matrix between weekly disease score and weather of preceding one and preceding three weeks. Disease intensity was found positively correlated with RH and rains while as the correlation with temperature was negative. It followed similar trend with all the three sets of weather parameter as weather of preceding one week and that of 3rd and preceding three weeks have contributed to the extent of 57, 50 and 51%, respectively. The study further reveals that optimum temperature for all the events of pathogenesis besides inoculum dispersal in this case lies below 25oC while as the optimum relative humidity must be above 90% and this all is made possible when it rains at least once a week in the summer.
The fungus Phoma sclerotioides, causal agent of brown root rot, is associated with winterkill and poor spring regrowth of alfalfa and other forage legumes in regions with harsh winters. In the ...continental United States, it has been reported in Wyoming, Idaho, Montana, Minnesota, and Wisconsin. A symptomatic alfalfa root collected in 2003 in northern New York tested positive for the pathogen using PCR based sequence-characterized amplified region (SCAR) markers. To evaluate the distribution and prevalence of the pathogen in the Northeast, alfalfa and birdsfoot trefoil plants were collected from forage production fields in New York in spring 2004 and in New Hampshire, New York and Vermont in spring 2005. Isolations were made from roots and crowns, and diagnosis of the pathogen was based on morphological characterization of axenic cultures and confirmed by PCR. The pathogen appears to be wide-spread in forage production fields in all three states. Disease incidence levels exceeded 20 percent in multiple fields, and, in the 2005 survey, 8 of 10 fields sampled in New York, 6 of 7 fields sampled in Vermont, and 5 of 6 fields sampled in New Hampshire carried the pathogen. Pathogenicity testing is in progress. This is the first report of brown root rot in the eastern United States.
The successful management of ray blight disease of pyrethrum, caused by infection with Phoma ligulicola in Tasmania relies upon the strategic use of the fungicide, azoxystrobin. The sensitivity of ...isolates exposed to one or two applications of azoxystrobin, was compared to a small number of isolates from an unexposed population. A sensitivity test based on conidial germination was conducted at concentrations of 0, 0.01, 0.04, 0.16, 0.625, 2.5, 50 and 100 mu g azoxystrobin/ml in 2% water agar (WA). The mean EC sub(50) for the exposed population was 0.07 mu g/ml, whilst for the unexposed population was 0.08 mu g/ml. Resistance factors in the exposed population ranged from 0.1 to 2.4. This information serves as baseline data for tracking sensitivity changes in the future.
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