Alternaria Tenuissima Research Articles

A new species of Pythium hydnosporum as a pathogen associated with vine decline of melon (Cucumis melo L.) in Iraq

Several pathogenic fungi have become an important vine decline of cantaloupe melone (Cucumis melo L.). In 2021, root rot on cantaloupe was observed during the harvest phase in the fields in Penjwen and Shahrazoor in Sulaimani governorate of Northern Kurdistan region Iraq. This present study was conducted to isolate the causal agent of fungi in lesions of root rot of cantaloupe. A total of 16 fungal isolates were obtained of which isolates Monosporascus cannonballus, M. eutypoides, Acremonium vitellinium, Fusarium oxysporium, F. equiseti, Macrophomina phaseolina, Saccharomyces kudriavzevii, F. robinianum, Rhizopus arrhizus, Botrytis cinerea, Cytospora eucalypticola, F. falciforme, Pythium hydnosporum, Alternaria tenuissima, Rhizoctonia solani and Phytophthora colocasiae were obtained from root melon. Identification of all fungal isolates was based on using both morphological characteristics and molecular analysis, on internal transcribed spacer (ITS1, ITS4, LSU) are primers that are used for identification. DNA sequences of the fungal pathogen were identified as Pythium hydnosporum a new pathogenic fungi causal agent of cantaloupe vine decline. A pathogenicity test was conducted to verify Koch's postulates and P. hydnosporum was observed to cause root rot of melon, symptoms of the disease were similar to those seen in the field.

Complete genome sequence of a novel mitovirus identified in the phytopathogenic fungus Alternaria tenuissima.

In this study, a novel positive-sense single-stranded RNA (+ ssRNA) mycovirus, Alternaria tenuissima mitovirus 1 (AtMV1), was identified in Alternaria tenuissima strain YQ-2-1, a phytopathogenic fungus causing leaf blight on muskmelon. The genome of AtMV1 is a single RNA molecule that is 3013 nt in length with an A + U content of 66.58% and contains a single open reading frame (ORF) using the fungal mitochondrial genetic code. The ORF was predicted to encode a 313-amino-acid RNA-dependent RNA polymerase (RdRp) with a molecular mass of 35.48 kDa, which contains six conserved motifs with the highly conserved GDD tripeptide in motif IV. The 5' and 3' untranslated regions were predicted to fold into stem-loop and panhandle secondary structures. The results of a BLASTp search revealed that the amino acid (aa) sequence of RdRp of AtMV1 shared the highest sequence similarity (51.04% identity) with that of Sichuan mito-like virus 30, a member of the genus Duamitovirus within the family Mitoviridae. Phylogenetic analysis based on the aa sequence of the RdRp suggested that AtMV1 is a novel member of the genus Duamitovirus. To our knowledge, this is the first report of the complete genome sequence of a new mitovirus infecting A. tenuissima.

The complete mitogenome of Alternaria tenuissima (Kunze) Wiltshire 1933 (Pleosporaceae), a fungus causing apple leaf blotch disease

Alternaria tenuissima (Kunze) Wiltshire 1933 is a plant pathogenic fungus mainly causing leaf blotch disease. Here, we de novo assembled mitochondrial genome of A. tenuissima isolate AT-1224. The total mitogenome size is 57,475 bp with 29.00% G + C content. The genome contained 12 coding genes and 15 hypothetical proteins, 34 transfer RNA (tRNA) genes and 2 ribosomal RNA (rRNA). There are 227 SSR repeats, range from 2 to 4 base pairs, most five repeats were AT (144), AAT (54), AG (33), AC (13) and AAG (5). The results also found 13 tandem repeats (>100 bp), the largest repeat were forward 2 times located from 13,405 to 20,024 bp and 25,549 to 32,168 bp. Phylogenetic analysis based on 17 species complete mitogenomes indicated that A. tenuissima mitogenome was closest to 2 species, A. solani and A. alternata, sister clade to 6 species, representing Curvularia clavate, Exserohilum rostratum, Exserohilum turcicum, Bipolaris cookie, Bipolaris oryzae and Bipolaris sorokiniana. Further analysis among common fungus in local apple orchards using mitochondrial protein-coding genes revealed A. tenuissima were closing to 2 Alternaria fungi and a fungus representing Phoma sp. These results provide a basic reference for identification and evolution studies of A. tenuissima on apple trees.

Identification of fungal species associated with gall oak (Quercus infectoria Oliv.) decline in Iran.

The gall oak (Quercus infectoria Oliv.) tree is one of the most important and valuable forestry species in the Northern Zagros forests in the west of Iran. Gall oak decline is considered to be one of the most important diseases currently affecting the oak Zagros forests in Iran. The main objective of the present study, conducted in the years 2021-2023, was to investigate the possible role of fungi as causative agents of gall oak dieback in the Zagros forests of Iran. Wood samples were taken from gall oak trees showing canker, dieback, and internal wood discoloration symptoms. Fungal isolates recovered from gall oak trees were identified based on cultural and morphological characteristics, as well as phylogenetic analyses using DNA sequencing of the internal transcribed spacer region of rDNA (ITS) and partial beta-tubulin (tub2). Achaetomium aegilopis, Alternaria tenuissima, Apiospora intestine, Botrytis cinerea, Coniochaeta sp., Coniothyrium palmarum, Coniothyrium sp., Cytospora rhodophila, Dialonectria episphaeria, Diatrype sp., Diatrypella macrospora, Endoconidioma populi, Fonsecazyma sp., Fusarium ipomoeae, Jattaea discrete, Kalmusia variispora, Microsphaeropsis olivacea, Neoscytalidium dimidiatum, Paecilomyces lecytidis, Paramicrosphaeropsis eriobotryae, Paramicrosphaeropsis ellipsoidea, and Seimatosporium pezizoides were identified from diseased trees. Pathogenicity tests were performed by artificial inoculation of excised branches of healthy gall oak trees under controlled conditions and evaluated after 35 days by measuring the discolored lesion length at the inoculation site. N. dimidiatum was the most virulent species and caused the longest wood necrosis within 35 days of inoculation. In the greenhouse test, only some species induced typical symptoms of canker. All isolated fungi are reported for the first time on gall oak trees in the world.

Identification, fermentation optimization, and biocontrol efficacy of actinomycete YG-5 for the prevention of Alternaria leaf spot disease in star anise

Star anise (Illicium verum), a valuable spice tree, faces significant threats from fungal diseases, particularly Alternaria leaf spot. This study investigates the potential of a soil-derived actinomycete strain, YG-5, as a biocontrol agent against Alternaria tenuissima, the causative pathogen on Alternaria leaf spot in star anise. Through comprehensive morphology, physiology, biochemistry, and genetic analyses, we identified the isolate as Streptomyces sp. YG-5. The strain exhibited broad-spectrum antimicrobial activity against several plant pathogens, with inhibition rates ranging between 36.47 to 80.34%. We systematically optimized the fermentation conditions for YG-5, including medium composition and cultivation parameters. The optimized process resulted in an 89.56% inhibition rate against A. tenuissima, a 14.72% improvement over non-optimized conditions. Notably, the antimicrobial compounds produced by YG-5 demonstrated stability across various temperatures, pH levels, and UV irradiation. In vivo efficacy trials showed promising results, with YG-5 fermentation broth reducing Alternaria leaf spot incidence on star anise leaves by 56.95%. These findings suggest that Streptomyces sp. YG-5 holds significant potential as a biocontrol agent against Alternaria leaf spot in star anise cultivation, offering a sustainable approach to disease management in this valuable crop.

Fungal endophytes Fusarium solani SGGF14 and Alternaria tenuissima SGGF21 enhance the glycyrrhizin production by modulating its key biosynthetic genes in licorice (Glycyrrhiza glabra L.).

To identify promising fungal endophytes that are able to produce glycyrrhizin and enhance it in licorice and the mechanisms involved. Fifteen fungal endophytes were isolated from Glycyrrhiza glabra L. rhizomes among which SGGF14 and SGGF21 isolates were found to produce glycyrrhizin by 4.29 and 2.58µg g-1 dry weight in the first generation of their culture. These isolates were identified as Fusarium solani and Alternaria tenuissima, respectively, based on morphological characteristics and sequence analysis of internal transcribed spacer, TEF1, ATPase, and CAL regions. Subsequently, G. glabra plants were inoculated with these fungal isolates to examine their effect on glycyrrhizin production, plant growth parameters and the expression of key genes involved in glycyrrhizin pathway: SQS1, SQS2, bAS, CAS, LUS, CYP88D6, and CYP72A154. Endophytes were able to enhance glycyrrhizin content by 133%-171% in the plants. Natural control (NC) plants, harboring all natural endophytes, had better growth compared to SGGF14- and SGGF21-inoculated and endophyte-free (EF) plants. Expression of SQS1, SQS2, CYP88D6, and CYP72A154 was upregulated by inoculation with endophytes. LUS and CAS were downregulated after endophyte inoculation. Expression of bAS was higher in SGGF21-inoculated plants when compared with NC, EF, and SGGF14-inoculated plants. Two selected fungal endophytes of G. glabra can produce glycyrrhizin and enhance glycyrrhizin content in planta by modulating the expression of key genes in glycyrrhizin biosynthetic pathway.

ПОЧВЕННЫЕ БАКТЕРИИ ИЗ АВТОХТОННЫХ МИКРОБНЫХ СООБЩЕСТВ ЦЕНТРАЛЬНОЙ СИБИРИ В БИОЛОГИЧЕСКОЙ ЗАЩИТЕ ПШЕНИЦЫ ОТ ALTERNARIA TENUISSIMA

The most powerful soil bacteria from autochthonous microbial communities of Central Siberia against phytopathogenic fungi Alternaria tenuissima were selected. Isolation from soil samples and cultivation of bacterial isolates were performed on the artificial nutrient medium for bacteria PD-agar. Antagonistic activity was measured on GRM Saburo. In this case, Alternaria tenuissima was sown in a dish on GRM Saburo, and the selected bacterial strains were sown around the micromycete. As a result of joint growth of the test culture and soil bacteria, the most powerful antagonists in the suppression zone of Alternaria tenuissima were identified. The most powerful bacteria-antagonists in reducing the intensity and prevalence of root rot were identified by the method of artificial infection of Alternaria tenuissima. Before infection with micromycete, bacterization of spring wheat seeds Novosibirskaya-15 with the studied bacterial isolates was carried out. Mathematical processing of the obtained results was fulfilled by one-way variance analysis and two-sample F-test for variance. The results of the study on the use of soil autochthonous antagonist microorganisms in biological protection of spring wheat from the causative agents of root rot Alternaria tenuissima showed that the studied bacterial isolates statistically significantly (p < 0.01) reduced the intensity and prevalence of this disease. The maximum effect in reducing the intensity and prevalence of the disease was shown by isolates B2 and B4 (according to preliminary identification of Bacillus sp.). Also, the studied bacterial strains showed a positive effect on the length of sprouts. At the same time, isolate B2 showed a statistically significant (p < 0.001) effect on the length of spring wheat sprouts. The stimulating effect was manifested in an increase in the length of sprouts compared to the control. Therefore, this strain can be recommended not only for protection against Alternaria tenuissima, but also for stimulating wheat growth.

Dieback of royal poinciana (Delonix regia) trees induced by Alternaria tenuissima and its impact on photochemical efficiency of photosystem II

In Saudi Arabia, poinciana (Delonix regia) trees are afflicted by dieback disease, manifesting symptoms that can lead to complete defoliation and, ultimately, the demise of trees in advanced stages. To investigate the dieback symptoms, samples were collected from branches at the transition zone. Identification of fungal isolates involved the assessment of colony and spore morphology, as well as PCR amplification and sequencing of the internal transcribed spacer (ITS) gene regions. The predominant fungus isolated was Alternaria tenuissima. Chlorophyll a fluorescence quenching and polyphasic fluorescence induction kinetics were conducted to assess the photochemical and nonphotochemical processes of Photosystem II (PSII) in stem barks affected by dieback. The dieback disease significantly reduced chlorophyll content, potentially hindering PSII performance in terms of maximum photochemical efficiency, quantum yield, electron flux, and photoprotection. These findings suggest that compromised photochemistry and photoprotection render poinciana trees inoculated by dieback less efficient in utilizing light energy and more susceptible to photoinhibition. Additionally, this study implies the use of non-invasive chlorophyll fluorescence techniques as a phenotyping tool for assessing photoprotective and photoinhibitory responses of stems to dieback stress.

Diversity of causal agents of Pseudostellaria heterophylla leaf spot from Guizhou Province, China

AbstractPseudostellaria heterophylla, a valuable Chinese herbal medicine, is widely cultivated in China, with a planted area of 5402.7 hm2 in Shibing County, Guizhou Province. The occurrence of leaf spot disease represents a significant challenge in the production area. In this study, 30 samples of P. heterophylla exhibiting symptoms of leaf spot were collected from three primary production areas in Guizhou Province. Following isolation and purification, 51 isolates were classified into two genera based on both cultural and conidial characteristics, along with ITS sequence data. Fourteen representative strains were selected for morphological and multigene molecular identification, which revealed that these representative strains were affiliated with Alternaria arborescens species complex (SC), Alternaria tenuissima, Alternaria gaisen, and Sclerotiophoma versabilis. The isolation rates of Alternaria and Sclerotiophoma were 84.3% and 15.7%, respectively. Pathogenicity tests confirmed the identity of the causal agents and demonstrated varying levels of aggressiveness among the different genera and species of pathogens towards P. heterophylla leaves. This study marks the first identification of A. arborescens SC, A. gaisen, and S. versabilis as pathogens causing leaf spot in P. heterophylla in China.

Morpho-molecular charactrization of endophytic fungi associated with aquilaria malaccensis lam.

A total of 26 fungal isolates were identified from Aquilaria malaccensis Lam. (Agarwood). Among them Aspergillus flavus Link type-1, Aspergillus flavus Link type-2, Aspergillus niger Tiegh. type. 1, Aspergillus niger Tiegh. type. 2, Aspergillus sp. 1, Aspergillus sp. 2, Alternaria alternata (Fr.) keissl., Curvularia lunata (Wakker) Boedijn, Penicillum digitatum (Pers.) Sacc., Penicillium commune Thom, Penicillum italicum Wehmer, Penicillium sp. 1, Penicillium sp. 2, Penicillium sp. 3, Penicillium sp. 4, Eupenicillium sp. 1, Eupenicillium sp. 2, Sphaeropsis sp. Sacc. and Harknessia sp. Cooke. were identified by morphological analysis and Alternaria tenuissima (Kunze) Wiltshire, Alternaria palandui Ayyangar, Fusarium sporotrichioides Sherb., Lasiodiplodia theobromae (Pat.) Griffon & Maubl., Lasiodiplodia pseudotheobromae A.J.L. Phillips, A. Alves & Cronus, Diaporthe hongkongensis R.R. Gomes, Glienke & Cronus and Diaporthe perseae (Zerova) R.R. Gomes, Glienke & Cronus were identifed upto genus level by morphological analysis, which were later on identified and confirmed at species level by molecular analysis. Among these isolated fungal species- Alternaria palandui, Diaporthe hongkongensis, Diaporthe perseae and Lasiodiplodia pseudotheobromae have been reported as newly recorded species and Harknessia sp. and Sphaeropsis sp. were reported as new generic records for Bangladesh. Bangladesh J. Plant Taxon. 31(1): 141-154, 2024 (June)

Rapid detection of Alternaria spp. by PCR in the newly created forest plantations on the drained bottom of the Aral Sea

Salinization and drought are the most important abiotic stress factors causing significant impact to the agriculture of Uzbekistan. To eliminate the negative consequences of the drying of the Aral Sea, large-scale works are currently being conducted on this territory to create protective forest plantations of halophytic trees and shrubs. An important issue in the protection of forest plantations is the isolation, identification and monitoring of phytopathogenic fungi associated with these forest plantations. The study's objective was to isolate Alternaria fungi from Haloxylon aphyllum (Minkw.) Iljin, Tamarix hispida Willd., T. ramossisima Ledeb. and to also apply a diagnostic marker using PCR assays to detect and identify Alternaria pathogens in these plants. As a result of the study, 10 strains of Alternaria fungi were isolated from plant samples of black saxaul – Haloxylon aphyllum, and two tamarisk species – Tamarix hispida, Tamarix ramossisima. The dominant species was: Alternaria tenuissima (Kunze) Wiltshire. β-tubulin gene was used as a molecular marker to distinguish and identify Alternaria spp in 34 leaf samples of Haloxylon aphyllum, Tamarix hispida and Tamarix ramossisima. The primer set used in the PCR assay was shown to be capable of detecting the presence of Alternaria in the leaves. Therefore, a β-tubulin-based diagnostic marker can be widely applied for monitoring of Alternaria infecting a wide-range of halophytic trees and shrubs in the protective forest plantations.

Evaluation and Control of Alternaria tenuissima Causing Leaf Spots in Blue Honeysuckle in China.

Blue honeysuckle is emerging as a popular edible fruit and is also used in folk medicine. However, from June to August 2021, a serious leaf-spot disease affected the yield and quality of blue honeysuckle in Harbin, Heilongjiang Province, China; the species and characteristics of the pathogens responsible for the disease were unknown. In this study, 30 fungal isolates were obtained from infected blue honeysuckle leaves and identified as Alternaria tenuissima based on morphological and molecular characteristics and phylogenetic analyses. To the best of our knowledge, this is one of the first studies to identify A. tenuissima as the causal agent of blue honeysuckle leaf spots in China. Pathogenicity tests of the isolates revealed that most isolates were moderately pathogenic. All blue honeysuckle cultivars tested were found to be susceptible to 30 A. tenuissima isolates. In addition, elder, Dahurian rose fruit, sea buckthorn, rowan, hawthorn, bird cherry, and sorb could be infected by A. tenuissima isolates, while European cranberry bush and Nanking cherry were not infected. A. tenuissima isolates were highly sensitive to prochloraz (EC50 ≤ 0.50 μg ml-1) with 86.21% efficacy at 400 μg ml-1 in the field trials. Therefore, crop rotation and application of chemical fungicides are considered to control the disease-causing leaf spots in blue honeysuckle. These results provide a basis for controlling A. tenuissima in blue honeysuckle in China.

Bacillus-derived consortium enhances Ginkgo biloba's health and resistance to Alternaria tenuissima.

Bacillus, as a plant-growth-promoting rhizobacteria, can enhance the resistance of plants to phytopathogens. In our study, Bacillus strains showing excellent biocontrol were screened and used to control ginkgo leaf blight (Alternaria tenuissima). Four biocontrol Bacillus strains-Bsa537, Bam337, Bso544, and Bsu503-were selected from 286 isolates based on their capacity to inhibit pathogens and promote plant growth. The four Bacillus strains significantly improved the resistance of ginkgo to leaf blight. This was especially the case when the four strains were used as a mixture, which contributed to a decrease in lesion area of >40%. Hence, a mixture of Bacillus strains was used to control ginkgo leaf blight in the field. Treatment efficiency varied from 30% to 100% (average 81.5%) and was higher than that of the control (-2% to -18%, average - 8.5%); the antioxidant capacity of the treated ginkgo was also stronger. In addition, ginkgo biomass increased as a result of treatment with the Bacillus mixture, including leaf weight, area, thickness, number of lateral roots and root weight. Furthermore, the Bacillus mixture improved the ginkgo rhizosphere soil by boosting the number of beneficial microorganisms, lowering the number of pathogens and hastening soil catabolism. The Bacillus mixture improved the health status of ginkgo by protecting it from pathogen attack, promoting its growth and improving the microorganism community in the rhizosphere. This work closes a technological gap in the biological control of ginkgo leaf blight, investigates application methods for compound Bacillus biofertilizers and establishes a framework for the popularity and commercialization of these products. © 2024 Society of Chemical Industry.

Identification the Pathogen Cause a New Apple Leaf Blight in China and Determination the Controlling Efficacy for Five Botanical Fungicides.

Alternaria leaf blight has recently been described as an emerging fungal disease of apple trees which is causing the significant damage in the apple-growing areas of Tianshui and Jingning, Gansu, China. In the present study, the pathogen species involved in apple leaf blight and its biological characteristics were identified, and the inhibitory activity of different botanical fungicides against the pathogen was evaluated in vitro. Four strains were isolated from the symptomatic areas of necrotic apple leaves, and initially healthy leaves showed similar symptoms to those observed in orchards after inoculation with the ABL2 isolate. The ABL2 isolate was identified as Alternaria tenuissima based on the morphological characteristics of its colonies, conidiophores, and conidia, and this was also confirmed by multi-gene sequence (ITS, OPA10-2, Alta-1, and endoPG) analysis and phylogenic analysis. The optimum temperature, pH, carbon source, and nitrogen source for the growth of A. tenuissima mycelia were 28 °C, 6-7, soluble starch, and soy flour, respectively. In addition, the botanical fungicide eugenol exhibited the highest inhibitory effect on the mycelial growth and conidia germination of A. tenuissima, and the median effective concentration (EC50) values were 0.826 and 0.755 μg/mL, respectively. The protective and curative efficacy of eugenol were 86.85% and 76.94% after inoculation in detached apple leaves at a concentration of 4 μg/mL. Our research provides new insights into the control of apple leaf blight disease by applying botanical fungicides.

In vitro antagonist activity of cedar Trichoderma species against three cedarwood lignivorous fungi

Cedarwood lignivorous fungi cause significant damage to cedar groves. In Morocco, the losses of cedar wood are estimated at more than 30% due to these fungi, which cause two primary diseases known as M'jej and Saboune. In this study, we are interested in the isolation and molecular identification of parasitic fungi and trichoderma species in the cedar groves of Tazekka National Park and Azrou forest, as well as the biological control of these lignivorous fungi by Trichoderma species. The molecular characterization identified three phytopathogenic fungi: Paecilomyces maximus, Pleurostoma richardsiae, and Alternaria tenuissima. Under in vitro conditions, Trichoderma species (Trichoderma lixii, Trichoderma simmonsii, and Trichoderma viridescens) were more effective. They significantly inhibited the mycelial growth of the studied pathogens through the production of volatile metabolites and mycoparasitic capacity. A maximum percentage exceeding 73 % was recorded. In addition, the direct confrontation tests showed a great capacity of Trichoderma isolates to colonize the medium in competition with the pathogenic fungi, with colonization percentages that reached 81.25 %. In general, Trichoderma agents significantly inhibited the growth of pathogens through various inhibition mechanisms, including colonization of the space, mycoparasitism, or the production of volatile or diffusible metabolites. An in-vivo study is recommended to take advantage of this ecological biocontrol solution.

Metabolomic and Transcriptomic Analyses Reveal the Molecular Mechanism Underlying the Massive Accumulation of Secondary Metabolites in Fenugreek (Trigonella foenum-graecum L.) Seeds.

Fenugreek (Trigonella foenum-graecum L.) is a traditional medicinal plant for treating human diseases that is widely cultivated in many countries. However, the component and related metabolic pathways are still unclear. To understand the changes in expression of the component and related genes during seed development, this study employed metabolomic and transcriptomic analyses and integrative analysis to explore the metabolites and pathways involved in the growth of fenugreek. The antifungal activity of the fenugreek seeds was also analyzed. A total of 9499 metabolites were identified in the positive ion mode, and 8043 metabolites were identified in the negative ion mode. Among them, the main components were fatty acyls, prenol lipids, steroids, steroid derivatives, flavonoids, and isoflavonoids. Among these enriched pathways, the top 20 pathways were "flavone and flavonol biosynthesis", "isoflavonoid biosynthesis", and "flavonoid biosynthesis". 3,7-Di-O-methylquercetin, flavonoids, pseudobaptigenin, isoflavonoids, methylecgonine, alkaloids, and derivatives were the most significantly upregulated metabolites. There were 38,137 differentially expressed genes (DEGs) identified via transcriptomic analysis. According to the KEGG pathway enrichment analysis, 147 DEGs were significantly enriched in "flavonoid biosynthesis". Ten DEGs of the six key enzymes were found to be involved in three pathways related to flavonoid and alkaloid synthesis in fenugreek. The antifungal activity test revealed the inhibitory effect of the ethanol extract of fenugreek seeds on Alternaria tenuissima (Kunze)Wiltshire and Magnaporthe oryzae. These findings further prove that the use of botanical pesticides in fenugreek fruit has research value.

ПОЧВЕННЫЕ БАКТЕРИИ ИЗ АВТОХТОННЫХ МИКРОБНЫХ СООБЩЕСТВ ЦЕНТРАЛЬНОЙ СИБИРИ В БИОЛОГИЧЕСКОЙ ЗАЩИТЕ ПШЕНИЦЫ ОТ ALTERNARIA TENUISSIMA

The aim of the study is to find the strongest soil microorganisms from autochthonous microbial communities of Central Siberia against phytopathogenic micromycetes Alternaria tenuissima. The object of the study is autochthonous soil bacteria isolated from the soils of the Krasnoyarsk forest-steppe in the Sukhobuzimsky District. Soil samples were taken from under spring wheat Novosibirskaya 15 and from under perennial grasses. The soil cover is represented by ordinary leached chernozem. Ammonium nitrate was used (34.7 kg/ha active ingredient). The climatic conditions are moderately dry and continental. The studies were carried out in 2022–2023. Antagonistic activity was measured on the GRM Saburo. With a general growth of the test culture and soil bacteria, the strongest antagonists were found in the suppression zone of Alternaria tenuissima. The identification of the most powerful bacterial antagonists in reducing the intensity and prevalence of root rot was carried out using the method of artificial infection with Alternaria tenuissima. Before infection with micromycete, bacterization of spring wheat seeds Novosibirskaya 15 with the studied bacterial isolates was carried out. Mathematical processing of the obtained results was carried out by one-way variance analysis and two-sample F-test for variance. The results of the study on the use of soil autochthonous antagonist microorganisms in biological protection of spring wheat from the causative agents of root rot Alternaria tenuissima showed that the studied bacterial isolates statistically significantly (p < 0.01) reduced the intensity and prevalence of this disease. The maxi-mum effect in reducing the intensity and prevalence of the disease was shown by isolates B2 and B4. Also, the studied bacterial strains showed a significant effect (p < 0.001) on the length of sprouts. The greatest increase in length in spring wheat sprouts was in the experimental variant with strain B2. This strain can be recommended not only for protection against Alternaria tenuissima, but also for stimuli-ting wheat growth.

Utilization of Antagonistic Bacteria for Managing Potato Brown Leaf Spot Caused by Alternaria tenuissima and Plant-Associated Biochemical Changes During Disease Development

Utilization of Antagonistic Bacteria for Managing Potato Brown Leaf Spot Caused by Alternaria tenuissima and Plant-Associated Biochemical Changes During Disease Development

Isolation and identification of Bacillus subtilis and its potential in biocontrol of phytopathogenic fungi

In the work, based on morphological, cultural, biochemical properties and on the basis of the 16S rRNA gene, a local strain of bacteria Bacillus subtilis TM was isolated from saline soils of the Fergana region of Uzbekistan. The strain was registered with NCBI under the number: OR944512.1. It was revealed that the strain Bacillus subtilis TM exhibits high antagonistic activity against the phytopathogenic fungi Fusarium verticillioides, Fusarium solani, Aspergillus orchaceus, Alternaria alternata, Fusarium culmorium, Alternaria tenuissima with an inhibition zone of 40-60 mm. At the same time, the B. subtilis TM strain showed moderate antagonistic activity against Fusarium oxysporium, Penicillium chrysogenium (with an inhibition zone of 22-23 mm) and relatively less antagonistic activity against Cladosporium sp (with an inhibition zone of 12 mm).

Fungal Endophytes of Moringa (Moringa oleifera L.), Neem (Azadirachta indica) and Lavender (Lavandula angustifolia) and Their Biological Control of Fusarium Wilt of Banana

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), significantly affects the productivity of the banana crop in the field. Currently, there are no effective control measures available, and therefore, there is an urgent need to develop novel strategies to control the spread of the disease. Biological control is a promising strategy for the management and control of the disease. The aim of this study was to identify fungal endophytes associated with Moringa (Moringa oleifera), Neem tree (Azadirachta indica) and Lavender (Lavandula angustifolia) and their antifungal activities against Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4). We isolated 69 fungal endophytes from different tissues of M. oleifera, A. indica and L. angustifolia and screened for antifungal activity against Foc TR4. Six fungal endophytes exhibited highest antagonistic activity against Foc TR4 based on dual-culture assays. Based on morphology and ITS gene sequence analysis, the selected six endophytes were identified to be related to Alternaria alternata (MB7 and NR3), Neofusicoccum parvum (LB1), Fusarium oxysporum (LR1), Talaromyces amestolkiae (MB14) and Alternaria tenuissima (NB6). The culture filtrates of the six fungal endophytes (LB1, LR1, MB7, MB14, NB6 and NR3) exhibited more than 50% inhibition of mycelial growth of Foc TR4 in vitro and were producers of β-1,3-glucanase. The six fungal endophytes showed biocontrol efficacy against Fusarium wilt in pot experiments. The findings from this study demonstrate that fungal endophytes LB1, LR1, MB7, MB14, NB6 and NR3 should be explored as biocontrol agents and biofertilizers in banana production.