Rhizopus Stolonifer Research Articles

Detection of Seed Mycoflora Associated with Indian Mustard (Brassica juncea L.) by Various Seed Health Testing Methods

India is one of the major oilseed crops grower. Mustard (Brassica juncea L.) is an important oilseed crop second after groundnut. Mustard is majorly grown in India which carry many seedborne diseases which causes not only seed rot, seedling blight but also reduction in quality of seed parameters which results qualitative and quantitative yield losses. In standard agar plate seed germination per centage ranged from 78.50 to 85.00% and in Modified PDA method ranged from 70.00 to 78.00%. In standard agar plate and Modified PDA method highest per cent of infected seed was observed in Pusa bold 74.25% and 64.50%, respectively. In two seed health testing methods (SHT) were evaluated standard agar plate show higher seed mycoflora than modified PDA method. All two methods were found effective and reliable for the detection of seedborne fungi such as Alternaria brassicae, Fusarium oxysporum, Aspergillus niger, Aspergillus flavus, Rhizoctonia solani, Penicillium sp. and Rhizopus stolonifer isolated from mustard seeds of varieties Krishna, Kranti, Local and Pusa bold.

Antifungal Effects and Postharvest Diseases Control Potential of E, E-2, 4-Nonadienal against Rhizopus stolonifer.

Pathogenic microorganisms are a significant cause of food spoilage, adversely affecting both product quality and human health. This study evaluated the antifungal activities of 34 aldehydes against foodborne and plant pathogenic fungi, identifying 8 promising lead compounds. Among them, E, E-2, 4-nonadienal exhibited optimal effects against Rhizopus stolonifer with an EC50 of 11.29 μg/mL. In vitro assays demonstrated that E, E-2, 4-nonadienal significantly impact R. stolonifer through both direct contact and fumigation. The preliminary mode of action (MOA) studies indicated that it effectively inhibited spore germination, disrupted ergosterol biosynthesis, and induced oxidative stress, affecting the permeability of the fungal cell membrane and altering mycelial morphology. Additionally, E, E-2, 4-nonadienal significantly reduced soft rot in spore-infected stored cherry tomatoes and showed low toxicity. Thus, aldehydes, exemplified by E, E-2, 4-nonadienal, are potential food and agricultural preservatives, offering efficiency, safety, and cost-effectiveness.

The potential of helichrysum italicum essential oil-infused alginate coatings and film for prolonging the shelf-life of cherry tomatoes

This study aimed to develop edible coatings and films using sodium alginate (1 % Alg) and varying concentrations of Helichrysum italicum essential oil (HIEO) (0.3 % and 0.5 %) for cherry tomato preservation. The treatments consisted of Alg, Alg/0.3 % HIEO, and Alg/0.5 % HIEO. The physico-chemical, mechanical, water vapor permeability, optical, thermal, and antifungal properties of these coatings and films were examined. Scanning electron microscopy and Fourier transform infrared spectroscopy analyses showed that the addition of HIEO resulted in a heterogeneous morphology and slight chemical structural changes in the Alg film. The Alg/0.5 % HIEO films exhibited improved water vapor permeability, antioxidant capacity, ultraviolet light barrier properties, elongation at break, and thermal stability. Additionally, 0.5 % HIEO significantly reduced the mycelial growth of Botrytis cinerea (in vitro), making Alg/0.5 % HIEO the optimal coating. Cherry tomatoes coated with Alg/0.5 % HIEO and stored at 25 °C and 60 % relative humidity for 18 d showed reduced weight loss (5.22 ± 1.45 %) and preserved firmness (6.43 N). This coating also inhibited the Rhizopus stolonifer lesion diameter by 61.36 % (in vivo). In conclusion, Alg/0.5 % HIEO coatings are promising sustainable active packaging solutions for cherry tomato storage applications.

Production and characterization of biosurfactants from lactic acid bacteria in Dadiah for strawberries edible coating

Biosurfactants are amphiphilic components applied in various fields, one of which is preserving agricultural products. Biosurfactants can be used as additives in edible coatings to prevent microbial adhesion by reducing surface tension on the fruit surface. They also play a role in increasing the moisture barrier and slowing down the physiological changes of fruit. Nonetheless, biosurfactants were often produced by non-GRAS bacteria. GRAS biosurfactant-producing bacteria are urgently needed for application in food products. This study aims to isolate and characterize biosurfactant-producing strains of lactic acid bacteria from Dadiah and evaluate their efficacy in reducing microbial adhesion on strawberries. From four selected isolates found in Dadiah, Lactiplantibacillus plantarum was the best candidate, producing biosurfactant with index emulsification (EI24) of 64.48 ± 0.37% with a CMC of 1 g/l. LC-MS and FT-IR characterized the biosurfactants as glycolipids. The rate of antibacterial and anti-adhesive tests on Escherichia coli ATCC 8739 were 18.79 ± 5.23% and 55.26 ± 0.02%, while on Staphylococcus aureus ATCC 6738 were 31.60 ± 2.63% and 74.63 ± 0.00% at a concentration of 3000 mg/l. However, no anti-fungal activity against Rhizopus stolonifer and Aspergillus niger was observed at the same concentration. Compared to SDS, biosurfactants demonstrated non-toxicity with an LC50 value of 2.94 x 108 mg/l. A combination of 1% chitosan reduced the number of fungal cells by 29.76 ± 3.25% on 125 mg/l biosurfactant and bacterial cells by 31.91 ± 5.06% on 1000 mg/l biosurfactant after 10 days, indicating their potential to reduce fruit spoilage and enhance microbial anti-adhesive properties of edible coatings.

Fungicidal Potentials of Leaf and Bark Extracts of Bryophyllum pinnatum on Cowpea (Vigna unguiculata L.) Seed Fungi

In Nigeria, Cowpea (Vigna unguiculata [L.] Walp) is an important grain legume which besides being a food crop serves as a major source of income for rural households. The action of pathogens on stored seeds causes huge post-harvest and economic losses to cowpea farmers in Nigeria. This research was aimed at isolating and identifying the spoilage pathogens of cowpea seed and testing the potentiality of ethanol extracts of Bryophyllum pinnatum on the isolates. Spoilt cowpea seed samples were purchased from different markets in Anambra State. They were transported to Alpha Research Laboratory, Awka in sterile polythene bags for microbial isolation. The spoilage organisms were isolated from the seeds through microbial culture. The media used for the isolation were Sabouraud Dextrose Agar and Potato Dextrose Agar. Pathogenic fungi were isolated from the spoilt cowpea seeds. The findings indicated that Aspergillus aculeatus, Fusarium solani, Penicillium citrinum, Rhizopus stolonifer, and Aspergillus flavus were present. The pathogenicity test also showed that the above organisms were responsible for cowpea spoilage. These isolates were tested for their in-vitro antifungal activity against the leaf and bark extracts of Bryophyllum Pinnatum. The antifungal activity ethanol extracts of Bryophyllum pinnatum on the isolated microorganisms were investigated using the disc method. Three different concentrations (25%, 50%, 100%) of extracts were used for the test. Fusarium solani showed the highest percentage of inhibition with antifungal medication while Penicillium citrinum showed the least percentage of inhibition with antifungal medication. The antifungal potential of Bryophyllum pinnatum extract on spoilage pathogens of stored cocoyam corms encourages more research on the active ingredient of the plant for easy use by farmers as alternative to commercial/ synthetic fungicides.

ISOLATION AND MOLECULAR IDENTIFICATION OF INDIGENOUS BACTERIOCIN-PRODUCING WEISSELLA CIBARIA

Globally, over 6.22 million deaths are associated with antibiotic resistance. Bacteriocins, a set of antimicrobial peptides synthesized on the ribosomes, are widely viewed as a potential answer to this issue. This is due to their pore-forming ability and antimicrobial activity against antibiotic-resistant pathogens. The aim of this study is to isolate bacteriocin-producing Weissella cibaria and evaluate its antimicrobial activity against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhi, Proteus mirabilis, Streptococcus sp., Candida sp. and Rhizopus stolonifer. Weissella cibaria man1 was isolated by inoculating deMan Rogosa Sharpe (MRS) broth with small pieces of ripe Mangifera indica (mango), 24-hour incubation at 370C, 10-fold serial dilution and plating on MRS agar. Molecular identification was achieved by DNA extraction, amplification of the 16S rRNA gene through polymerase chain reaction (PCR), agarose gel electrophoresis, gene sequencing, and BLASTN homology searches in the National Center for Biotechnology Information (NCBI). Antimicrobial activity of the bacteriocin was determined by agar well diffusion assay. Mangifera indica (mango) was found to harbor bacteriocin-producing Weissella cibaria man1. The bacteriocin (weissellicin man1) exhibited a broad spectrum of antimicrobial activity. Weissellicin man1 suppressed the growth of several target pathogens (Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus mirabilis, Candida sp. and Rhizopus stolonifer) but had no inhibitory action against Escherichia coli, Streptococcus sp., Staphylococcus aureus. In conclusion, weissellicin man1 from Weissella cibaria man1 has a broad-spectrum of antimicrobial action. These findings will facilitate further evaluation of the antimicrobial potency of weissellicin man1.

Evaluating the multifaceted impact of Cephalaria extract on dough quality: Antioxidant, antimicrobial, and cytotoxic properties

SummaryCephalaria syriaca, known as cephalaria, is an annual, pilose plant with pink‐purple flowers growing wild in wheat fields. Viscoelastic properties of gluten‐free doughs can be improved by adding cephalaria. However, this addition results in some undesirable properties in bread such as bitter taste and dark internal colour. This study aimed to reduce these effects by obtaining cephalaria obtained from distilled water and ethanol extracts and to increase the potential use of extracts in bread production. Different proportions of water and ethanol extracts obtained from oil‐free cephalaria were added to bread by creating a model with Mixture Design, and the optimum concentration was determined by farinograph trials. The antioxidative, antimicrobial, and cytotoxic effects of extract and the effect of cephalaria on yeast activity were examined. Cephalaria extracts had no measurable antimicrobial effect and no antifungal effect on Rhizopus stolonifer, while an antifungal effect was found against A. niger and P. expansum. The IC50 value was found to be 4.15 mg mL−1 for ethanol extract while the water extract had no effect on cells. The addition of extract had no negative effect on the number of yeasts in sourdough fermentation. The study has improved the usage of cephalaria by using water and ethanol extracts in dough.

Antimicrobial Activity of Honey and Propolis from Alba County, Romania.

Investigating the quality of bee products obtained across different geographical regions and analyzing their antimicrobial activity is of significant interest to various scientific disciplines. This study focuses on comparing the antimicrobial activity of honey and propolis samples from different areas of Alba County, Romania. The quality parameters of five samples of two types of bee products (honey and propolis) were assessed. Then, the samples were tested to comparatively determine their antimicrobial properties against 12 species of bacteria (Escherichia coli, Salmonella typhimurium, Salmonella enteritidis, Salmonella anatum, Salmonella choleraesuis, Pseudomonas aeruginosa, Pseudomonas fluorescens, Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Bacillus subtilis, and Listeria monocytogenes) and 7 fungal strains (Candida albicans, Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Rhizopus stolonifer, Fusarium oxysporum, and Alternaria alternata). Of the bacterial strains, the most sensitive to the action of honey samples were the two strains of Staphylococcus followed by P. fluorescens. The two strains of Pseudomonas and L. monocytogenes were the most sensitive to the activity of propolis. Of the fungal strains, F. oxysporum was the most sensitive to the actions of both honey and propolis, followed by P. chrysogenum in the case of honey samples and the two Aspergillus strains in the case of propolis. These findings indicate that bee products are rich sources of bioactive compounds exhibiting strong antimicrobial properties and significant potential for the development of new phytopharmaceutical products.

Biodegradable soy protein isolate carvacrol coating controls soft rot on nectarines by enhancing defense response

Nectarine fruits are rich in nutrients, which are susceptible to fungal infection during postharvest, resulting in quality deterioration and decay. This study aimed to assess the effect of different concentrations of carvacrol and soy protein isolate coatings on the fungal infection and quality characteristics of nectarines during postharvest storage. The results showed that soy protein isolate carvacrol (SPI-C) coating inhibited the growth of Rhizopus stolonifer in vitro. The SPI-C coating significantly reduced the incidence of postharvest soft rot, maintained the postharvest quality of nectarines during storage. SPI-C coating induces the defense response to soft rot by enhancing the accumulation of phenolic, flavonoids and lignin, and up-regulating the expression of defense-related genes in nectarines. The SPI-C coating activated the transcription of antioxidant enzymes (CAT, SOD and POD) and eliminated ROS damage. The disease resistance response promotes the production of defense-related substances by upregulating the gene expression of PpPPO and PpPAL. In summary, SPI-C coating significantly reduces the incidence of postharvest soft rot, maintains the postharvest quality and induces defense response to soft rot by enhancing the expression of genes involved in phenylpropanoid metabolism in nectarines during storage.

Primary Screening of Fungi with Aflatoxin-Production Potential in Rotten Tomato sold at Shasha Market Akure

The present study aimed to isolate, characterise, and evaluate aflatoxin-producing fungus from rotting tomatoes sold in Shasha market, Akure. Rotten tomato fruits from the Shasha market in Akure were cultured on potato dextrose and malt extract agar that was made selective for fungi by adding chloramphenicol to inhibit bacteria. Results showed that fungal isolates have 1.40 to 3.30 x 103 sfu/g of total fungus. Penicillium spp., Rhizopus stolonifer, Mucor mucedo, and Phytophthora spp. had the lowest proportion of occurrence (4.76%), followed by Aspergillus flavus (33.33%) and Aspergillus niger (23.81%). Hepatoma, or liver cancer, and severe hepatitis are caused by aflatoxin, especially in underdeveloped nations like Nigeria. This study informs people that eating rotten tomatoes is harmful. To avoid aflatoxins-producing fungus contamination of tomato fruits, farmers and marketers must implement pre- and post-harvest procedures.

Evaluation of seed oil from Hura crepitans, Trichosanthes cucumerina and Thevetia nerifolia

The oil contents and fatty acid composition of three non-edible seed oils extracted using Soxhlet extraction with hexane as the solvent were presented. The physical and chemical properties of the oils were determined from which cetane number, biofuel potential, higher heating values, and antimicrobial activities were assessed. The dominant fatty acids were 49 % linoleic acid, 37 % pentadecenoic acid, and 38 % cis-10-heptadecenenoic acid for Hura crepitans (HC), Thevetia nerifolia (TN) and Trichosanthes cucumerina (TC), respectively. The seed oils were majorly unsaturated, with HC having the highest degree of unsaturation. Acid value, saponification value, iodine value, and free fatty acids were low compared to many reported values in literature. The cetane values were generally high because the oils have a reasonable amount of saturated fatty acid, with TN having the highest cetane number. The low iodine value and saponification value make the biofuel potential and higher heating value to be high with TN having the highest in both and thus the best seed oil for biofuel. However, TN and HC have no antimicrobial activity to Klebsiella pneumoniae (gram -ve), Staphylococcus aureus (gram +ve), Escherichia coli (gram -ve), Bacillus subtilis, Enterobacter aerogenes, Candida albican, Rhizopus stolonifer, Fusarium Solani, Aspergillus flavus and Candida tropicalis, while TC has broad spectrum of activity against all tested bacteria and fungi, except Klebsiella pneumoniae.

Level of Aflatoxins in Selected Cereals in Ekiti State, Nigeria

Aflatoxins are family of toxins produced by certain fungi found on agricultural crops such as maize (corn), peanuts, cottonseed, and nuts. The ingestion of such mycotoxin contaminated grains by animals and human beings has enormous public health significance. This has necessitated the evaluation of effects of Asparagus africanus (Lam - whole plant) extracts on aflatoxins production by fungi isolated from selected foods in Ekiti State, Nigeria. A total of 240 food samples were collected across the 16 Local Government areas in rural open markets. The food samples analyzed were: Igbemo rice Oryza sativa igbemo curtivar), maize (Zea mays) and groundnut (Arachis hypogaea). Aflatoxin-producing fungi and non aflatoxin producing fungi were isolated and identified using morphological method of identification on PDA and microscopic with lactophenol cotton blue stain. The molecular identification of the isolates was done using internal transcribe spacer (ITS) region. A total of 70 samples that contain Aspergillus spp were subjected to ELISA test to quantify and identify types of aflatoxins that were present in them. It was revealed that four types of aflatoxins were present in the food samples (AFB1, AFB2, AFG1, and AFG2). Also, different species of isolates were obtained from the samples viz: Aspergillus flavus, Aspergillus niger, Rhizopus stolonifer, Mucor mucedo, A. parasiticus, Neurospora crassa, Botrytis cinerea, Fusarium oxyporum and Penicillium oxalicum. Aspergillus flavus was prevalent among the isolates. The molecular identification showed three of the isolates were Aspergillus flavus with different percentage of ITS4 rDNA identity. The level of aflatoxins in some of the food samples analyzed is of great concern because of its ability to cause disease (in man and animal) and these toxins are introduced mostly during storage, that is, post-harvest.

Identification and Prevalence of Fungal Species in Stored Sorghum Grains Surveyed at Bodija and Oyo Town Markets in Oyo State and Ikire and Iwo Town Markets in Osun State, Western Nigeria

This study investigated the identification and prevalence of fungal species in stored sorghum grains surveyed at Bodija and Oyo town markets in Oyo State and Ikire and Iwo town markets in Osun State, Western Nigeria using appropriate standard methods. Six distinct fungal species were isolated from the sorghum grains and identified through macroscopic and microscopic examination. These species included Aspergillus flavus, A. niger, A. tamarii, A. terreus, Fusarium sp., and Rhizopus stolonifer. The prevalence of fungal contamination was found to be higher in the markets of Oyo State compared to those in Osun State. Additionally, Aspergillus flavus and A.niger were the most prevalent fungal species, while Rhizopus stolonifer was the least prevalent.

Direct antifungal activity of methyl salicylate on soft rot caused by Rhizopus stolonifer and its membrane targeting mechanism

Methyl salicylate (MeSA) plays a significant role in various physiological metabolic processes of plants, however, reports on the antifungal activity were rare. This study aimed to investigate the direct antifungal activity of MeSA against Rhizopus stolonifer and to explore its antifungal mechanism at the membrane targeting level. Our study demonstrated that MeSA had antifungal activity. MeSA inhibited the mycelial growth and spore germination of Rhizopus stolonifer, and acted on the plasma membrane, changed the integrity and permeability of the cell membrane, leaked cell contents, induced reactive oxygen species (ROS) accumulation, stimulated membrane lipid peroxidation, changed the morphology of the mycelium, and finally caused apoptosis. In addition, in vivo experiments, MeSA significantly delayed the occurrence of soft rot of various fruits and vegetables. The results indicated that MeSA has direct antifungal activity for Rhizopus stolonifer, and proposed its antifungal mechanism from membrane targeting.

Evaluation of antifungal activities of some Indian dietary spices against pathogenic Rhizopus arrhizus and Rhizopus stolonifer

Rhizopus arrhizus and Rhizopus stolonifer are pathogenic fungi responsible for causing ‘soft rot’ disease in fruits and vegetables, as well as life-threatening ‘mucormycosis’ in animals and humans, especially immunocompromised hosts. The use of synthetic fungicides and chemical preservatives to inhibit microbes is being challenged due to their toxic effects on human health and the environment. This has prompted researchers to investigate novel antimicrobials that are natural and safe. Current study aimed to evaluate the antifungal activities of essential oils (EOs), powdered (PWD) forms, and water extracts (WEs) of ten Indian dietary spices (Allium sativum (Als), Brassica nigra (Brn), Cinnamomum zeylanicum (Ciz), Cuminum cyminum (Cuc), Curcuma longa (Cul), Mentha piperita (Mep), Ocimum sanctum (Ocs), Syzygium aromaticum (Sya), Trigonella foenum-graecum (Trf), and Zingiber officinale (Zio)) against R. arrhizus (NCIM877) and R. stolonifer (NCIM1139). Spice agar method was used for investigating antifungal potential of PWD spices. Impregnated paper disc method and broth dilution technique were followed for screening the antifungal activities of EOs and WEs. Results revealed that EOs of six spices (Als, Brn, Ciz, Cuc, Mep, Sya), and PWD forms of four spices (Brn, Ciz, Cuc, Sya) inhibited the growth of both fungi in culture media, effectively. WEs of all ten spices remained ineffective in arresting the growth of tested fungal strains. R. stolonifer was found more sensitive compared to R. arrhizus towards tested substances. Based on these findings, further in vivo studies on PWD forms of Ccb, Ccm, and Sya and EOs of Als, Brn, Ccb, Ccm, Mep, Ocs and Sya may establish spices as ‘botanical antimicrobials’ to prolong the shelf life of valuable horticultural crops by arresting the growth of R. arrhizus and R. stolonifer.

Evaluation of the probiotic, anti-microbial, anti-biofilm, and safety properties of Levilactobacillus brevis Lb13H

In this research, the probiotic potential, anti-microbial, anti-biofilm, and safety properties of Levilactobacillus brevis Lb13H were investigated. Also, Gaussian Process Regression (GPR) model was applied to predict some of experimental parameters. The strain demonstrated resistance to acidic pH, gastric and intestinal juices, and bile salts. Additionally, the strain exhibited 45.34% surface hydrophobicity, 36.55% auto-aggregation capacity, 26.30% co-aggregation, 10.20% adhesion to Caco-2 cells, 42.57% cholesterol removal, and 48.63% radical-scavenging properties. The probiotic strain was able to inhibit the adhesion of Listeria monocytogenes to intestinal cells by 31.30%, and its competitive inhibition percentage was 37.5%. Furthermore, the replacement of L. monocytogenes with the strain was measured at 22.10%. The most significant antimicrobial effect was observed against L. monocytogenes, while the least effect was noted against Rhizopus stolonifer. Haemolytic activity, DNase production, and biogenic amine production were not observed in the strain, which was also found to be sensitive to the antibiotics ciprofloxacin and chloramphenicol. The cell-free supernatant of L. brevis Lb13H effectively inhibited and degraded biofilm formation by L. monocytogenes, achieving effectiveness rates of 40.80% and 36.60% respectively. The results of modeling indicated that there is not any difference between actual and predicted data and GPR can predict the variables with high accuracy.

Fungal pathogens of mold of winter wheat grains in Rostov region

Long-term monitoring of the colonization of winter wheat grain by fungal mold pathogens that negatively affect the quality of grain during storage, reducing the quality of seed material, food grains and forage, showed that a high level of occurrence on the grain ofRostov winter wheat samples for the period 2014–2021 was manifested by mold fungiMucorspp.,Aspergillusniger,Aspergillusglaucus,Aspergillus flavus, species of the genusPenicillium.Relatively low occurrence was observed inRhizopus nigricansandCladosporium herbarumspecies.Mold pathogens are producers of the most dangerous mycotoxins: ochratoxinA(species ofPenicillium,Aspergillus niger,A. glaucus), aflotoxinB1 (A.flavus), rhizonins (Rhizopusspp.), etc.In the regions ofSouthernRussia, with severe drought in the soil and on the lower parts of plants, the accumulation of the fungusPenicillium purpureogenumis often noted, for some time it could become dominant.When restoring the level of moisture supply, a decrease in the occurrence ofP. purpureogenumwas observed, often to zero, and an increase in the occurrence of mucor fungi (Fusarium solani,F.semitectum), non-circulatingMycelia sterilia fungi, etc., a noticeable increase in the total density of fungal colonies.The highest level of external infection of grain was due to colonization of grain by fungi from thePenicilliumgroup, as well asA. glaucusandA. niger, the highest level of internal infection was caused by thePenicilliumgroup,Rhizopus nigricans,A. niger.The dominance of external infection over internal infection was observed during colonization by penicilli and aspergillus, the dominance of internal over external infection by rhizopus and cladosporium.

Catalytic activity of chitinase encapsulated with alginate and its application in a biosensor for postharvest fungal detection

This research aimed to preserve the chitinase catalytic activity using alginate and zinc oxide nanoparticles (ZnO-NPs), to evaluate its thermal stability at 37 ºC, 50 ºC, and 70 ºC and its ability to detect Rhizopus stolonifer, Colletotrichum fragariae, and Alternaria alternata in a capacitive transducer-based biosensor. The ZnO-NPs measured less than 100 nm. The phosphate buffer-citric acid was a better solvent than water. Al+ZnONPs Ch showed the highest thermal stability at 37 ºC and 50 ºC (2 IU) for 45 d. Conversely, the free enzyme lost its activity from day 1–28 at 37 ºC (3.3 IU-2.8 IU), and alginate-encapsulated chitinase (AlCh) had the lowest activity at 50 ºC during 45 d (1.3 IU). Chitinase, alginate, and the ZnO-NPs were confirmed for FTIR spectra. The Al+ZnONPs Ch had the best response in the biosensor, observing a decrease in electrical frequency when the concentration of the tested fungi increased (106 spores mL−1 =100–250 kHz and 104 spores mL−1 = 400 kHz). In conclusion, at 37 ºC and 50 ºC, the chitinase had a stable catalytic activity compared to the remaining treatments, and it could be used to detect fungi in a biosensor at concentrations from 103 to 106 spores mL−1.

Synergistic biocontrol mixture: free-cell extract with β-glucanase activity and chitosan against Thielaviopsis paradoxa, Colletotrichum gloeosporioides, and Rhizopus stolonifer

Biocontrol, which uses antagonistic microorganisms to manage plant diseases, holds promise for reducing postharvest losses but faces challenges due to varied pathogen responses. In response, biocontrol mixtures were proposed to enhance the antagonistic effect. This study evaluates the efficacy of chitosan and extracellular glucanase (EG) from Wickerhamomyces anomalus, both individually and combined, against Thielaviopsis paradoxa, Colletotrichum gloeosporioides, and Rhizopus stolonifer. The maximum inhibition of mycelial growth by chitosan for these fungi was 90.25% at 3 mg/mL, 14.2% at 5 mg/mL, and 56.28% at 3 mg/mL, respectively. Additionally, chitosan significantly inhibited spore germination across all fungi. While W. anomalus cells prevented mycelial filament association, EG alone had minimal impact on mycelial development but inhibited spore germination in a concentration-dependent manner. Combining EG with chitosan enhanced spore germination inhibition, notably achieving 98.18%. The biocontrol mixture effectively protected fruit under laboratory-controlled conditions, suggesting a robust biocontrol strategy for postharvest fungal disease management.

Physiological and sanitary quality of sorghum seeds under the effect of oxalic and salicylic acid

Sorghum is one of the world's most important cereal crops, but it is susceptible to several diseases, particularly fungal diseases, with seeds being the main vehicle for dissemination. The objective of this study was to evaluate the effects of salicylic acid (SA) and oxalic acid (OA) on the physiological and sanitary quality of sorghum seeds. The seeds of Sorghum bicolor (L.) were immersed for 1 hour in solutions of OA (0.5, 1.0, 1.5, and 2.0 mM) and SA (0.5, 1.0, 1.5, and 2.0 mM). A treatment with Captan® fungicide was also used, and the control group was immersed in distilled H2O for 1 hour. Variables from seed vigor tests and fungal incidence tests were evaluated. The control group showed the highest germination rate. However, among the treatments, the doses of 1 mM OA and 0.5 mM SA resulted in higher germination in the first germination count. The application of 1 mM OA and both doses of SA (0.5 mM and 1 mM) promoted a greater seedling vigor index (GVI). Seeds treated with 1 mM OA and doses of 0.5, 1, 1.5, and 2.0 mM SA, as well as those treated with fungicide, had the highest emergence rates, and with 1.5 mM SA, the highest length of the longest root (LVEI). Seedlings from seeds treated with 0.5, 1, and 1.5 mM SA and with 0.5 and 1.5 mM had the highest coleoptile length (CPA). The 0.5 mM dose of SA reduced the incidence of Aspergillus flavus, and the doses of 2 mM OA and 1, 1.5, and 2 mM SA reduced the incidence of Rhizopus stolonifer to 0%. SA provided the best physiological and health effects for sorghum seeds, making it the best treatment.