Growth Of Fungal Isolates Research Articles

Characteristics of Zymoseptoria tritici isolates from the Russian Federation and the Republic of Kazakhstan by azoxystrobin sensitivity

Septoria tritici blotch is one of the harmful diseases of wheat cultivars cultivated in the Russian Federation and the Republic of Kazakhstan. The purpose of the research was to study a sample of Zymoseptoria tritici isolates obtained from the Saratov and Tambov (Russian Federation) and Almaty (Republic of Kazakhstan) regions according to the degree of the azoxystrobin sensitivity, as well as to evaluate these isolates for the presence of the G143A mutation using PCR-RFLP analysis. The azoxystrobin sensitivity of Z. tritici isolates was evaluated by studying the growth restriction of cultures on a nutrient medium (concentrations of active drug in the medium were 100, 10, 1, 0.1, 0.01 mg/l.). In the control, on the 21st day of cultivation, the diameter of the colonies of Z. tritici strains varied from 14.24±1.43 mm to 19.53±0.66 mm. Azoxystrobin had a significant inhibitory effect on the growth of fungal isolates from the Tambov region: EC50 is 1.72 μg/l, from the Almaty region EC50 is 2.36 μg/l, from the Saratov region EC50 is 2.63 μg/l. The results of biotesting made it possible to identify isolates of Z. tritici resistant to azoxystrobin: 277-22-5, 277-22-13 (from Kazakhstan); 104-23-9, 104-23-10 (from the Saratov region); 19-23-5, 19-23-8 (from the Tambov region). PCR-RFLP method made it possible to identify mitochondrial mutations G143A in selected fungal isolates, which are associated with the development of resistance to fungicides in the causative agent of septoria. This work is the beginning of a more in-depth study of the sensitivity of the economically significant phytopathogen Z. tritici to fungicides in the territories of Russia and the Republic of Kazakhstan.

BIODEGRADATION OF GLYPHOSATE CONTAINING HERBICIDE BY SOIL FUNGI

Ten fungal isolates were isolated from two herbicide-contaminated soil farms obtained from Amoyo and the University of Ilorin environment in Kwara State after enrichment with mineral salt medium (MSM) supplemented with glyphosate-containing herbicide. The growth of fungal isolates was efficiently stimulated by the organophosphorus herbicide. Fungi isolated were subjected to screening by varying the herbicide concentrations from 0.1 to 3%, which is prepared with MSM. This screening showed that all the fungal isolates had the ability to act in the biodegradation process. However, varying degradative potentials were observed, as some had heavy growth while others had only slight or no growth as the concentrations of the herbicide increased. The ten fungal isolates were characterized and identified as Aspergillus niger, Penicillum spinulosum, Aspergillus terrus, Aspergillus flavus, Fusarium oxysporum, Mucor spp., Aspergillus oryzae, Aspergillus tamari, Rhizopus stolonifer, and Trichoderma koningii, and these were reduced to six after screening with 3% concentration of the herbicide. Four isolates (A. niger, F. oxysporum, Mucor spp., and A. flavus) were selected based on their growth ability on the medium during screening and were used in the biodegradation study. However, there is an increase in fungal dry weights ranging from 8.60 to 18% for 12 days. This shows that these fungi can be employed in the biodegradation of herbicides since they are potentially effective species and are environmentally safer alternative to protect the soil from the contamination of glyphosate-containing herbicide residues.

Prevalence and Eco-friendly Management of Dry Rot of Potato in Rawalpindi and Islamabad

The dry rot disease of potato is caused by Fusarium species is a disastrous disease of potato as postharvest disease that can contribute huge losses of potato during storage. During current study market based survey was done in Rawalpindi and Islamabad during year 2021to estimate the disease prevalence and diseases losses during storage of different potato verities in different months. It revealed that maximum dry rot disease prevalence of potato was 1.90%, 1.86% in Rawalpindi and Islamabad respectively. Fungi isolates were isolated from diseases samples and were preserved and identified on the basis of cultural and morphological keys. The pathogenicity test confirmed the virulence of pathogenic fungal isolates. Among the cultivars, average loss of dry rot of potato within the three months; August and September, October were found in cultivar Kuroda and Lady Rosetta was 1.36% and 1.21% respectively in Rawalpindi while 1.86% and 1.48% average loss was estimated in Kuroda and Lady Rosetta respectively in Islamabad. During disease management studies in which biocontrol agent (Pseudomonas fluorescence, Bacillus subtilis and Bacillus cereus) were used during the dual culture technique and P. fluorescence was found most effective which reduced the 70% growth of fungal isolates and the maximum zone of inhibition 16mm was calculated. These preliminary postharvest disease studies will ultimately a source of information for the researchers and industrialist to develop cost effective and ecofriendly management against dry rot disease of potato during storage conditions.

In vitro: stem cutting a simple technique for determination aggressive potential of fungal isolates causing root rot disease of grapevine

Pathogenic soil borne fungi causing epidemic root rot disease on grapevine and high loss of plant growth and fruit yield. Fast detection of aggressive fungal isolates is the first tool for introduce selection effective a agent for management disease progress. In vitro two simple techniques based on stem cutting of grapevine i.e., mycelial growth and cell wall degrading enzymes activities were evaluated for screening of aggressive fungal isolates in comparsion with classical pathogenicity test. Fourteen isolates of fungi associated with root rot disease of grapevine plants i.e. Fusarium oxysporumi Schlechtend, Fusarium solani (Mart.) Sacc, Botryodiplodia theobromae, Rhizoctonia solani Kuhn and Macrophomina phaseolina (Tassi) Gold. were tested and pathological action on grapevine plant (Cv.crimson) under soil artificially infested by classical method with their mycelial growth,cell wall degrading enzymes activities on stem cutting of grapevine as well as each fungal isolates of shoot and root compare the control. Fungal isolate of Botryiodiplodia theobromae No. (7) was the most isolate recorded high and significant root rot (100%) incidence and disease severity on grapevine plants followed by Fusarium avenacum isolate No. (11) and Fusarium solani isolate No. (12). Positive correlation co-efficient was observed between mycelial growth of fungal isolates tested on stem cutting of grapevine plants and root rot disease incidence and their disease severity followed by their production pectinase and cellulase enzymes. So, mycelial of fungal growth on stem cutting of grapevine is a good and simple of opportunity technique for determination aggressive degrees of fungal isolates in vitro as alternative accuracy, very short time test and very shape cost than classical pathogenicity test.

Physiological variability of Macrophomina phaseolina (Tassi) Goid. Isolates causing root rot of castor

The fungus Macrophomina phaseolina is the devastating fungus of many crops. For this study, infected maize samples were collected from castor growing areas of Gujarat. Twenty-five isolates of M. phaseolina were isolated from infected castor samples and their growth was evaluated at 20, 25, 30, 35 and 40°C as well as at 5.0, 5.5, 6.0, 6.5, 7.0, 7.5 and 8.0 pH. The growth of fungal isolates was significantly affected by different levels of temperature and pH. Among different five temperature levels, significantly maximum mean growth (89.53 mm) was observed at 35 ºС temperature followed by 30 ºС(82.46 mm) after four days of incubation on PDA medium. Among different seven pH levels, significantly maximum mean growth of dry mycelial (352.42 mg) was recorded at pH 7.0 followed by pH 6.5 (313.70 mg) and pH 6.0 (311.02 mg), however pH 6.5 and pH 6.0 were statistically at par with each other. Among different seven pH levels, significantly maximum mean growth of dry mycelial (352.42 mg) was recorded at pH 7.0 followed by pH 6.5 (313.70 mg) and pH 6.0 (311.02 mg), clearly indicated the preference of isolates to particular range of pH. Mean dry mycelial weight was increased with increase in pH and temperature.

Production and efficacy of neem nanoemulsion in the control of Aspergillus flavus and Penicillium citrinum in soybean seeds

The search for alternative methods that are efficient to control phytopathogens is extremely important. For this purpose, the aim of this study is to develop and characterize Neem oil nanoemulsions (Azadirachta indica), as well as evaluate its applicability to fungi Aspergillus flavus and Penicillium citrinum in soybean seeds. Soybean seeds were placed with nanoemulsion containing different Neem oil concentrations (0.5%, 1%, 2%, and 3% w/v) for t1 (600 min) and t2 (30 min). Control samples (positive: infested and untreated; and negative: not infested and treated) were also carried out. Prior to the treatments, the formulated nanoemulsions were characterized by dynamic light dispersion, polydispersity, rheology, and stability test. Subsequently, the soybean seeds were treated with nanoemulsion and then tested for germination and health. The nanoemulsion showed a mean droplet diameter of 59 ± 0.6 nm, and a viscosity of 2.542 ± 0.07 mPa s. The droplet sizes in the nanoemulsion were stable for a period of 20 days and the polydispersity remained around 0.209 ± 0.02. Neem oil had an inhibitory effect on the growth of fungal isolates, being that the highest antifungal activity was observed at the concentration of 3% (w/v) (28 mm inhibition zone for A. flavus and 25 mm for P. citrinum). Neem oil nanoemulsions were efficient against the studied fungi and did not present phytotoxic effects to the seeds. Nanoemulsion is easily accessible, economically viable and, in addition, less toxic than common synthetic pesticides. This study showed that Neem oil nanoemulsions have significant potential applications in agriculture.

The use of fluorescent powders to track autocontamination of emerald ash borer (Coleoptera: Buprestidae) by the entomopathogen Beauveria bassiana (Ascomycota: Hypocreales)

ABSTRACTWe evaluated the use of fluorescent powders for tracking dispersal by the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), of Beauveria bassiana isolates from an autocontamination device. Neither of the two DayGlow powders tested (Arc Yellow and Aurora Pink) interfered with fungal germination or growth, nor did they affect survival of beetles in the laboratory, or affect virulence of the fungus. The powders persisted at least 10 days out-of-doors on dead beetles in sticky band traps, and at least 14 days on pouches inside autocontamination traps. During field trials of autocontamination traps with powder-dusted fungal pouches in southwestern Ontario, 8.0% of the 4010 beetles captured in green prism and sticky-band traps were positive for fluorescent powders. Only half (46.2–57.8%) of the powder-positive beetles actually carried viable fungal conidia, as determined by plating of beetle rinses, possibly as a result of patchy growth of fungal isolates and reduced conidia production on pouch surfaces during the 16-day trapping experiment. The presence of viable conidia (either one or both isolates) on about 10% of beetles that did not carry any visible powder particles may be an indication of horizontal transmission of the fungus by beetles that had visited the autocontamination traps.

Efficacy of Cuminum cyminum essential oil on FUM1 gene expression of fumonisin-producing Fusarium verticillioides strains.

The purpose of this study was to evaluate the effect of Cuminum cyminum (C. cyminum) essential oil on the growth and FUM1 gene expression of fumonisin-producing Fusarium verticillioides (F. verticillioides) strains isolated from maize. All fungal strains were cultured on potato dextrose agar (PDA) slopes at 30°C for 7 days. The antifungal activity was evaluated by broth microdilution assay. One set of primers was F. verticillioides species specific, which selectively amplified the intergenic space region of rDNA. The other set of primers was specific to FUM1 gene region of fumonisin-producing F. verticillioides. FUM1 transcript levels were quantified using a reverse transcription-polymerase chain reaction (RT-PCR) protocol. Minimum inhibitory concentration (MIC) values of C. cyminum oil against F. verticillioides strains varied from 0.195 to 0.781 µl.ml(-1) (mean MIC value: 0.461 µl.ml(-1)) indicating 54.5% of the fungal strains inhibited at 0.390 µl.ml(-1). PCR analysis of FUM1 gene expression revealed that DNA fragment of 183 bp was amplified in all the isolates of F. verticillioides before treatment with C. cyminum essential oil. Based on RT-PCR analyses, reduction in the expression of fumonisin biosynthetic genes was significant only for FUM1 gene (p<0.05), while no effect was observed on ITS gene. This study showed that all F. verticillioides isolates were susceptible to C. cyminum essential oil, indicating a significant reduction in the growth of fungal isolates. In addition, this oil completely inhibited the expression of FUM1 gene in concentrations dose-dependently.

Effects of metals on the germination and growth of fungal isolates from New Caledonian ultramafic soils

Soils of New Caledonian mining areas have relatively high metal contents. Two ultramafic soils rich in extractable Mn, Fe, Ni and Co and two agricultural soils with much lower concentrations of metals were compared through different experiments. Microbial population numbers and their tolerance to Mn 2+ and Ni 2+ were estimated. The effect of five metals (Ni 2+, Co 2+, Fe 2+, Mn 2+ and Mg 2+) upon spore germination and mycelial growth was investigated for fungi isolated from the two types of soils. Nickel appeared to be the most toxic metal, but the other metals also had inhibitory effects at concentrations similar to those which occur in ultramafic soils. Spore germination was more sensitive to metals than mycelial growth. The toxic effects of the five metals were not cumulative when mixed together into the medium; antagonism between ions, partly neutralizing their effects may account for this. Fungal isolates from ultramafic soils appeared to be more tolerant to metals than those from agricultural soils. Some ultramafic soil isolates appeared to actually require the presence of metals, with their growth being stimulated by relatively high concentrations of these elements. Two fungal isolates of genera which are often common in agricultural soils (i.e. Curvularia and Fusarium), and which are not present in New Caledonian ultramafic soils were also tested. Curvularia was more sensitive to the five metals than all the other isolates and Fusarium was particularly inhibited by Ni 2+. However, a proportion of the spores of each isolate was able to germinate and to grow moderately well in the presence of relatively high metal concentrations. Their absence from ultramafic soils is thought to result from their elimination by competitors that are more tolerant to metals.