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Alternaria sect. Ulocladium: conidia and conidiophores. A-B. A. capsici-annui. C-D. A. oudemansii. E-F. A. alternariae. G-H. A. botrytis. Scale bars = 10 μm.
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Alternaria is a ubiquitous fungal genus that includes saprobic, endophytic and pathogenic species associated with a wide variety of substrates. In recent years, DNA-based studies revealed multiple non-monophyletic genera within the Alternaria complex, and Alternaria species clades that do not always correlate to species-groups based on...
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Citations
... --из семян перца (Сагдуллаева и др., 1990). В свете последних изменений в роде Alternaria и новых требований к идентификации его видов [2,3,4,42,43,44] эти сведения не могут быть приняты как достоверные и должны быть подтверждены в дальнейших исследованиях. ...
In recent years, the prevalence, and negative effects of small-spored species of the genus Alternaria increased on nightshade crops. They are becoming more common in crops than large-spored species. Over 25 small–spored species have been recorded on nightshade crops: 12 from the Alternaria section, 4 each from the sections Infectoriae and Ulocladioides, one species each from the other six sections. A. alternata, A. tenuissima, and sometimes other species are found everywhere on crops. The aggressiveness of these species to nightshade crops is usually higher than that of species from other sections, but degree of the virulence varies greatly among different isolates. There are reports of local outbreaks of diseases on nightshade crops caused by A. longipes, A. chlamydosporigena and species of the Ulocladioides section. In Uzbekistan, small-spored Alternaria species have been found on plants from various families, but confirmation of their identification is required, considering modern requirements.
Key words: Solanaceous crops, early blight, brown spot, Alternaria, small-spored species.
Аннотация. В последние годы на паслёновых культурах возрастает распространённость и вредоносность мелкоспоровых видов рода Alternaria. Они на посевах встречаются чаще, чем крупноспоровые. На паслёновых культурах зарегистрировано более 25 мелкоспоровых видов: 12 из секции Alternaria, по 4 – из секций Infectoriae и Ulocladioides, по одному виду из других шести секций. Повсеместно на посевах встречаются A. alternata, A. tenuissima, иногда и другие виды. Агрессивность этих видов к паслёновым культурам обычно выше, чем у видов из других секций, но степень её варьирует сильно у разных изолятов. Есть сообщения о локальных вспышках болезней на паслёновых культурах, вызванных A. longipes, A. chlamydosporigena и видами секции Ulocladioides. В Узбекистане мелкоспоровые виды обнаруживали на растениях из различных семейств, но требуется подтверждение их идентификации с учётом современных требований
Ключевые слова: Паслёновые культуры, альтернароз, бурая пятнистость листьев, Alternaria, мелкоспоровые виды.
Аннотация. Кейинги йилларда Alternaria туркуми кичикспорали турларининг итузумдош экинларда учраши кўпаймоқда ва улар каттаспорали турларга нисбатан кўпроқ учрамоқда. Ушбу экинларда 25 тадан кўп кичикспорали турлар, жумладан Alternaria секциясининг 12 тури, Infectoriae ва Ulocladioides секцияларидан 4 тадан ва яна 6 та секциядан биттадан турлар қайд этилган. Итузумдош экинларда дунёнинг барча жойларида A. alternata, A. tenuissima ва баъзан бошқа турлар кенг тарқалган. Одатда бу турлар ушбу экинларни бошқа секцияларнинг турларидан кучли зарарлайди, аммо алоҳида изолятларининг ўсимликларни зарарлаш даражалари кучли ўзгарувчан ва ҳар хил. Итузумдош экинларни айрим жойларда A. longipes, A. chlamydosporigena ва Ulocladioides секциясининг турлари ҳам кучли зарарлаганлиги хабар қилинган. Ўзбекистонда Alternaria туркумининг кичикспорали турлари ҳар хил оилаларга мансуб ўсимликларда учрайди, аммо замонавий талабларга биноан, уларнинг идентификацияси қайтадан исботланиши лозим.
Калит сўзлар: Итузумдош экинлар, альтернариоз, барг қўнғир доғланиши, Alternaria, кичикспорали турлар.
... The conidial bodies of large-spored species typically measure 60-100 μm in length and the small-spored species are less than 60 μm. The morphological criteria can be influenced by growth conditions, including substrate, light, and humidity, potentially undermining their reliability in characterizing the genus (Woudenberg et al. 2013). ...
Sunflower (Helianthus annuus L.) is a widely cultivated, fast-growing crop known for its seeds and oil, with substantial ecological and economic importance globally. However, it faces challenges from leaf diseases caused by Alternaria species, which threaten its yield. Three small-spored Alternaria species were isolated from leaf spot and blight symptoms on sunflower in Myanmar. All the species were determined based on morphological characterization and a multi-locus phylogenetic assessment of seven genes, including the internal transcribed spacer of rDNA region (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), RNA polymerase second largest subunit (RPB2), translation elongation factor 1-α (TEF1), Alternaria major allergen gene (Alt a 1), endopolygalacturonase gene (EndoPG), and an anonymous gene region (OPA10-2). The results introduced two new Alternaria species, A. myanmarensissp. nov. and A. yamethinensissp. nov., and a known species of A. burnsii, firstly reported from sunflower.
... PCR was performed using a Veriti TM 96-Well Thermal Cycler (Applied Biosystems, Singapore), ITS and 28S was amplified under the following reaction conditions: pre-denaturation at 94 • C for 30 s, followed by 35 cycles of denaturation at 94 • C for 30 s, annealing at 53 • C for 30 s, and elongation at 72 • C for 1 min, and a final elongation at 72 • C for 3 min. For rpb2 amplification, a touchdown PCR program was applied following the description by Woudenberg et al. [36]. The PCR products were separated via electrophoresis on agarose gels running for 20 min in a TAE buffer. ...
Leptosphaerulina leaf spot, caused by Leptosphaerulina trifolii, is a major disease of alfalfa (Medicago sativa), leading to noticeable losses. From 2022 to 2023, we collected samples of alfalfa with symptoms of the disease from different locations in Inner Mongolia, China. Nine fungal isolates recovered from these samples were identified through morphological traits and a maximum likelihood phylogeny based on concatenated partial sequences of ITS, 28S, and rpb2. A pathogenicity test on alfalfa confirmed the pathogenicity of the isolates on alfalfa. Analysis of physiological traits of L. trifolii revealed optimal mycelium growth at 20 °C and a pH range of 5 to 7, with soluble starch as the preferred carbon source and yeast extract as the optimal nitrogen source. The pathogen thrived in V8-juice agar and oat agar media. This study confirms L. trifolii as the causative agent of Leptosphaerulina leaf spot of alfalfa in Inner Mongolia and provides valuable insights into its optimal growth conditions. These findings enhance the understanding and management of this disease in alfalfa fields.
... For instance, Alternaria alternata (Fr.) Keissl. is a cosmopolitan species that has been reported as an endophyte and a pathogen from a wide range of plant hosts (Woudenberg et al., 2013;DeMers, 2022). We found consistent evidence for the association between both Melampyrum species and Heterophoma species. ...
Cronartium pini and C. ribicola are rust fungi that cause destructive diseases of pines ( Pinus spp.). These rusts spread via alternate hosts, among which Melampyrum spp., Veronica spp. and Impatiens spp. are important for C. pini and Ribes spp. for C. ribicola . Congeneric alternate hosts vary in their susceptibility to Cronartium rusts, but the reasons for this variation are not clear. To clarify whether internal, endophytic fungi could explain these differences, we investigated the temporal and spatial variation in fungal endophyte composition of C. pini -resistant M. pratense , V. chamaedrys and I. glandulifera , C. pini -susceptible M. sylvaticum , V. longifolia and I. balsamina , C. ribicola -resistant R. rubrum and C. ribicola -susceptible R. nigrum . In total, 2695 fungal endophytic isolates were obtained and classified into 37 morphotypes, with 1373 cultures isolated in early summer and 1322 in late summer. Fifty-two isolates were identified to species or genus level. The most common morphotypes were identified as Heterophoma sp. Some variation in the abundance of morphotypes occurred between collection sites, but the same morphotypes dominated across the sites and species. The diversity of morphotypes was higher in early September than in late June in all species and the same morphotypes dominated in both early and late season. The diversity of fungal endophytes was higher in resistant Veronica and Ribes than in susceptible congeneric species, but the results suggest that the diversity or abundance of culturable fungal endophytes does not explain the differences in the congeneric species’ susceptibility to rust fungi.
... The genus Alternaria, comprising around 300 distinct species, exhibits a global distribution within diverse environments [1,2]. These species exhibit a dynamic range of behaviours, alternating between saprophytic and parasitic strategies in response to host conditions, leading to challenges in definitive lifestyle classification [1,3,4]. ...
... The genus Alternaria, comprising around 300 distinct species, exhibits a global distribution within diverse environments [1,2]. These species exhibit a dynamic range of behaviours, alternating between saprophytic and parasitic strategies in response to host conditions, leading to challenges in definitive lifestyle classification [1,3,4]. Functioning as both plant pathogens and saprobes, Alternaria species target various plants such as grains, vegetables, and fruits, inflicting substantial agricultural losses. ...
Background
Alternaria blotch disease in Himachal Pradesh, India, caused by Alternaria spp., adversely affects apple cultivars, resulting in reduced fruit size and quality accompanied by premature leaf fall.
Methods and results
Sixteen Alternaria isolates from apple growing regions underwent comprehensive analysis including morphology, pathogenicity, and molecular characterization. Variations in conidiophore and conidia dimensions, shapes, and divisions were observed among isolates. Pathogenicity assays revealed differences in incubation periods, latent phases, and disease responses. Molecular characterization via nuclear ITS rDNA and RAPD analysis indicated 99–100% homology with Alternaria alternata, Alternaria mali, and other Alternaria spp., with a close phylogenetic relationship to Chinese isolates. Differentiation of isolates based on origin, cultural characteristics, and morphology was achieved using RAPD markers.
Conclusions
The study identifies diverse genotypes and morphotypes of Alternaria contributing to apple blotch disease in Himachal Pradesh. These findings highlight the complexity of the pathogenic environment and hold significant implications for disease management in apple orchards.
... Morphological characterization was based on microscopic and macroscopic features using pure fungal colonies grown in PDA medium and incubated at ± 24 °C. For microscopic observations, three-to five-day-old cultures were used, and the diagnostic features such as mycelium type, conidia shape, and size, presence or absence of septa, and other general characteristics were described according to Woudenberg et al. (2013), Marin et al. (2020), and Aveskamp et al. (2010). Conidia size was based on average length and width measurements of 30 randomly selected conidia. ...
... The pathogenic isolates of interest for the present study were identified as A. longipes, C. geniculatus, and P. herbarum. According to Woudenberg et al. (2013), A. longipes belongs to the section Alternata, a taxonomic group that includes several closely related Alternaria species, including A. alternata, A. alstroemeria, A. longipes, and at least fifteen others. In the present study, we found that isolate H3 had small conidia growing in chains, which is typical of the Alternata section, with more elongated beaks, darker coloration, and predominantly smoother walls compared to A. alternata. ...
Ipomoea hederifolia L. is a weed that is considered problematic in several tropical crops. Phytopathogenic mycobiota could provide an alternative approach to biological weed management in agriculture. The objective of this study was to isolate and identify phytopathogenic fungi against I. hederifolia, under the inundative approach to biological control. The isolated fungi were subjected to pathogenicity tests in the laboratory through bioassays on detached leaves. The response variables recorded were incubation period, disease incidence, and the area under the disease progress curve (AUDPC). The fungi of interest were characterized morphologically and identified by molecular studies. The most aggressive pathogen was evaluated in a greenhouse by bioassays on whole I. hederifolia seedlings, using two inoculation methods: (1) agar disks with mycelium and (2) conidial suspension. Three of the eight fungi obtained were found to have pathogenic potential against the weed and were identified as Alternaria longipes, Cochliobolus geniculatus and Phoma herbarum. In the detached leaf bioassays, the incidence of the disease was greater than 81% in all cases and the average incubation period was between 3.4 and 4.5 days. A. longipes was significantly the most aggressive isolate (AUDPC = 9.1). In the bioassays on whole seedlings, 83% and 33% of the seedlings were infected by A. longipes using methods (1) and (2), respectively, after 10 days. We conclude that our isolate of A. longipes could be useful as a possible biocontrol agent for this weed; however, it is important to continue the next research steps of the inundative approach to confirm its suitability.
... The fungal strains IIUI313 (the purified strain from the Madagascar periwinkle) and IIUI314 (the purified strain from the Cupressus plant), which had rapid growth and large biomass production, were selected to synthesize the NC. The isolated fungal species were identified phenotypically based on colonial and cellular morphology [30,31], followed by molecular characterization for genotypic identification. A former CTAB method [32] with certain modifications was used to extract the genomic DNA. ...
Multidrug-resistant wound infections are a global health threat and a leading cause of death, persisting despite available treatments due to antibiotic resistance, biofilms, and ineffective drug delivery systems. The aim of this study is to (i) formulate an innovative nano-drug delivery system (NDDS) based on a Carbopol nanoemulgel (NEG) co-loaded with neomycin-silver/zinc oxide nanocomposite (NC) that could fight clinical MDR and treat biofilm-forming wound pathogens through topical application, and (ii) assess its in vivo wound-healing potential. The silver/zinc oxide (Ag/ZnO) NC was synthesized by co-inoculating the metabolites of Aspergillus welwitschiae and Meyerozyma guilliermondii. The synthesized NC was then conjugated with neomycin and loaded into a Carbopol NEG for efficient topical delivery. The resulting Neo-Ag/ZnO NEG was characterized physicochemically (e.g., UV-visible [UV-Vis] spectrophotometry, field emission scanning electron microscopy, X-ray diffraction, and Fourier transform infrared [FTIR] spectroscopy), biologically (e.g., in vitro antimicrobial, antibiofilm, and hemolytic activities), and pharmacologically (e.g., drug content, ex vivo drug release behavior, and in vivo wound-healing potential). The physicochemical analysis confirmed the successful mycosynthesis of the Carbopol NEG-loaded Neo-Ag/ZnO NC. SEM depicted a crystalline polyhedral shape of the small NC (average particle size of 38 nm). FTIR studies showed a slight interaction with the drug and other bioactive moieties in the Carbopol NEG. The Neo content in the Carbopol NEG was as high as 98%, and a maximum release of 81% for Neo, Ag, and ZnO ions was noticed after 12 h. The NDDS appeared hemocompatible and displayed a minimal inhibition concentration of 0.002 µg/mL with the greatest antimicrobial potential against S. aureus (an inhibition zone of 46 mm) compared to other tested wound microbes (p < 0.05). Statistically significant wound-healing activity was found for NDDS (p = 0.0001) in comparison to the control at a concentration of 100 mg/mL. The results showed that this newly developed Carbopol NEG-loaded neo-Ag/ZnO NC appeared promising for controlling resistant skin infections and boosting wound regeneration.
... All isolates were checked morphologically under a light microscope and molecularly by PCR amplification and sequencing of the internal transcribed spacer (ITS) regions of the ribosomal RNA gene cluster to confirm their identity as belonging to A. alternata. In addition, following the method previously described by Woudenberg et al. (35)(36)(37), we randomly took 13 putative A. alternata isolates from across the seven greenhouses and obtained their sequences at the following six loci for species confirmation: glyceraldehyde-3-phosphate dehydrogen ase (gapdh), RNA polymerase second largest subunit (rpb2), translation elongation factor 1-alpha (tef1), Alternaria major allergen gene (Alta1), endopolygalacturonase (endoPG), and an anonymous gene region (OPA10-2). ...
Alternaria alternata is a ubiquitous soil-borne fungus capable of causing diseases in a variety of plants and occasionally in humans. While populations of A. alternata from infected plants have received significant attention, relatively little is known about its soil populations, including its population genetic structure and antifungal susceptibilities. In addition, over the last two decades, greenhouses have become increasingly important for food and ornamental plant production throughout the world, but how greenhouses might impact microbial pathogens such as A. alternata populations remains largely unknown. Different from open crop fields, greenhouses are often more intensively cultivated, with each greenhouse being a relatively small and isolated space where temperature and humidity are higher than surrounding environments. Previous studies have shown that greenhouse populations of two common molds, Aspergillus fumigatus and A. alternata, within a small community in southwestern China were variably differentiated. However, the relative contribution of physical separation among local greenhouses to the large-scale population structure remains unknown. Here, we isolated strains of A. alternata from seven greenhouses in Shijiazhuang, northeast China. Their genetic diversity and triazole susceptibilities were analyzed and compared with each other and with 242 isolates from nine greenhouses in Kunming, southwest China. Results showed that the isolation of greenhouses located <1 km from each other locally contributed similarly to the overall genetic variation as that between the two distant geographic regions. In addition, our results indicate that greenhouses could be significant sources of triazole resistance, with greenhouses often differing in their frequencies of resistant strains to different triazoles.
IMPORTANCE
Greenhouses have become increasingly important for food production and food security. However, our understanding of how greenhouses may contribute to genetic variations in soil microbial populations is very limited. In this study, we obtained and analyzed soil populations of the cosmopolitan fungal pathogen Alternaria alternata in seven greenhouses in Shijiazhuang, northeast China. Our analyses revealed high proportions of isolates being resistant to agricultural triazole fungicides and medical triazole drugs, including cross-resistance to both groups of triazoles. In addition, we found that greenhouse populations of A. alternata located within a few kilometers showed similar levels of genetic differentiation as those separated by over 2,000 km between northeast and southwest China. Our study suggests that greenhouse populations of this and potentially other fungal pathogens represent an important ecological niche and an emerging threat to food security and human health.
... The isolated fungi were identified based on the macroscopic features of colonies, observed under a Stemi DV4 stereomicroscope (Carl Zeiss, Oberkochen, Germany), and the micromorphological characteristics of reproductive structures, analyzed with the optical microscope Zeiss Axio Imager M1 (Carl Zeiss, Oberkochen, Germany) using AxioVision Release 4.6 software. For identification, appropriate identification keys were used [17][18][19][20]. ...
Two ancient wooden vessels, specifically a monoxyle (1st century BCE to 1st century CE) and shipwreck (15th to 17th century CE), were excavated in a well-preserved state east of the confluence of the old Mlava and the Danube rivers (Serbia). The vessels were found in the ground that used to be river sediment and were temporarily stored within the semi-underground exhibition space of Mammoth Park. As part of the pre-conservation investigations, the primary aim of the research presented was to characterize the culturable mycobiomes of two excavated wooden artifacts so that appropriate conservation procedures for alleviating post-excavation fungal infestation could be formulated. Utilizing culture-based methods, a total of 32 fungi from 15 genera were identified, mainly Ascomycota and to a lesser extent Mucoromycota sensu stricto. Soft-rot Ascomycota of genus Penicillium, followed by Aspergillus and Cephalotrichum species, were the most diverse of the isolated fungi. Out of a total of 38 isolates, screened on 7 biodegradation plate assays, 32 (84.21%) demonstrated at least one degradative property. Penicillium solitum had the highest deterioration potential, with a positive reaction in 5 separate plate assays. The obtained results further broaden the limited knowledge on the peculiarities of post-excavation soft-rot decay of archaeological wood and indicate the biochemical mechanisms at the root of post-excavation fungal deterioration.
... The fungal structures in the lesions corresponded to species of the Alternaria genus. However, in addition to morphological characterization, molecular characterization through phylogenetic studies of DNA sequences is essential to differentiate species within the genus (Woudenberg et al., 2013(Woudenberg et al., , 2015. Therefore, the present study aims to identify the Alternaria species that causes tamarillo leaf spot in Brazil through molecular, morphological characterization, and pathogenicity testing. ...
... The identity of the consensus sequences with other species of the Alternaria section was greater than 98 %, directing the selection of Alternaria spp. accessions classified as type (T) within this section (Lawrence et al., 2013;Woudenberg et al., 2013Woudenberg et al., , 2015. The access codes for the sequences used are available in Table 1. ...
... The species A. alternata belongs to the Alternaria section, within the Alternaria genus, and is known worldwide for causing diseases in more than 100 plant species, including Solanaceae plants (Rotem, 1994; Woudenberg et al., 2013). In Brazil, different studies were carried out to characterize the molecular diversity of Alternaria species associated with leaf spots on Solanaceae, especially on potatoes (Solanum tuberosum L.) and tomatoes (Solanum lycopersicum L.) (Lourenço Junior et al., 2009;Rodrigues et al., 2010). ...
