Reduction In Germination Research Articles

Oxidative stress, protein metabolism, and physiological potential of soybean seeds under weathering deterioration in the pre-harvest phase

Weathering deterioration affects seed quality, especially in areas with excessive rainfall. This study aimed to evaluate the oxidative stress, physiological quality, and protein metabolism of seeds of different soybean cultivars under weathering deterioration at the pre-harvest phase. Six soybean cultivars (BMX Apolo, DM 6563, NS 5959, NA 5909, BMX Potência, and TMG 1175) were subjected to simulated rainfall at the R8 stage. Each level was divided into two applications at 72-h intervals: 60 mm (30 + 30), 120 mm (60 + 60), and 180 mm (90 + 90). Then, the seeds were harvested and evaluated for physiological potential, antioxidative enzymes, hydrogen peroxide, malondialdehyde, proteins, and protease activity. The simulated rainfall allowed the variation in seed moisture, promoting a significant reduction in germination and seed vigor, especially at 120 and 180 mm levels. There were also reductions in antioxidative enzyme activity with weathering deterioration (mainly for catalase, ascorbate peroxidase, and peroxidase), accumulation of hydrogen peroxide and malondialdehyde, and reductions in protein content and protease activity. The proposed rainfall system is efficient in inducing weathering deterioration during the pre-harvest phase and its deleterious effects. Weathering deterioration in soybean seeds in the pre-harvest stage is directly influenced by genotype.

Assessing the heat sensitivity of Urdbean (Vigna mungo L. Hepper) genotypes involving physiological, reproductive and yield traits under field and controlled environment.

The rising temperatures are seriously impacting the food crops, including urdbean; hence efforts are needed to identify the sources of heat tolerance in such crops to ensure global food security. In the present study, urdbean genotypes were evaluated for heat tolerance under natural outdoor for two consecutive years (2018, 2019) and subsequently in the controlled environment of the growth chamber to identify high temperature tolerant lines. The genotypes were assessed involving few physiological traits (membrane damage, chlorophyll, photosynthetic efficiency, stomatal conductance, lipid peroxidation), reproductive traits (pollen germination % and pollen viability %) and yield related traits (total number of pods plant-1, total seeds plant-1, single seed weight and seed yield plant-1). Based upon these tested traits, PantU31, Mash114, UTTARA and IPU18-04 genotypes were identified as promising genotypes for both years under heat stress condition. Further confirming heat tolerance, all these four tolerant and four sensitive genotypes were tested under controlled environment under growth chamber condition. All these four genotypes PantU31, Mash114, UTTARA and IPU18-04 showed high chlorophyll content, photosynthetic efficiency, stomatal conductance, leaf area, pods plant-1, total seeds plant-1 and low reduction in pollen germination % and pollen viability under stress heat stress condition. Moreover, yield and yield related traits viz., pods plant-1, seeds plant-1, single seed weight and seed yield plant-1 showed very strong positive correlation with pollen germination and pollen viability except electrolyte leakage and malondialdehyde content. Thus, these genotypes could be potentially used as donors for transferring heat tolerance trait to the elite yet heat-sensitive urdbean cultivars.

Characterization of kefir yeasts with antifungal capacity against Aspergillus species.

Kefir is a fermented probiotic drink obtained by placing kefir granules in a suitable substrate. The kefir granules are a consortium of bacteria and yeasts embedded in a exopolysaccharide matrix. The aim of this research was the isolation and identification of yeasts from kefir of different origin, the evaluation of their antifungal capacity against Aspergillus spp., and the characterization of virulence related traits. Using RFLP of ITS1/ITS4 region, D1/D2 region sequencing, and RAPD techniques, 20 kefir isolates were identified as Geotrichum candidum, Pichia kudriavzevii, Pichia membranifaciens, Saccharomyces cerevisiae, and Candida ethanolica. Their antifungal capacity was evaluated by their conidia germination reduction, which allowed the selection of eight isolates with high to moderate conidia germination reduction against Aspergillus flavus and Aspergillus parasiticus. Furthermore, these selected isolates showed growth inhibition on contact in the dual culture assay for both Aspergillus species and 3 of them-belonging to S. cerevisiae and P. kudriavzevii species-generated volatile organic compounds which significantly affected the growth of both fungi. For the evaluation of virulence-related traits, growth at high temperatures, enzymatic activities, and the adhesion to Caco-2 cells were analyzed. The isolates did not present more than one positive virulence-related trait simultaneously. In particular, it is important to highlight that the adhesion capacity to the model of intestinal barrier was extremely low for all of them. According to the results obtained, further studies would be of interest for the possible use of these promising yeasts as biocontrol agents against fungi in food.

Seed Germination Ecology of Chenopodium album and Chenopodium murale.

Chenopodium album L. and Chenopodium murale L. are two principal weed species, causing substantial damage to numerous winter crops across the globe. For sustainable and resource-efficient management strategies, it is important to understand weeds' germination behaviour under diverse conditions. For the germination investigations, seeds of both species were incubated for 15 days under different temperatures (10-30 °C), salinity (0-260 mM NaCl), osmotic stress (0-1 MPa), pH (4-10), and heating magnitudes (50-200 °C). The results indicate that the germination rates of C. album and C. murale were 54-95% and 63-97%, respectively, under a temperature range of 10 to 30 °C. The salinity levels for a 50% reduction in the maximum germination (GR50) for C. album and C. murale were 139.9 and 146.3 mM NaCl, respectively. Regarding osmotic stress levels, the GR50 values for C. album and C. murale were 0.44 and 0.43 MPa, respectively. The two species showed >95% germination with exposure to an initial temperature of 75 °C for 5 min; however, seeds exposed to 100 °C and higher temperatures did not show any germination. Furthermore, a drastic reduction in germination was observed when the pH was less than 6.0 and greater than 8.0. The study generated information on the germination biology of two major weed species under diverse ecological scenarios, which may be useful in developing efficient weed management tactics for similar species in future agri-food systems.

Prevalence of fungi associated with seven wheat varieties and seed quality analysis

Seven varieties of wheat seeds, such as BARI Gom-25, BARI Gom-26, BARI Gom-27, BARI Gom-28, BARI Gom-29, BARI Gom-30 and Kanchan were studied to determine the prevalence of seedborne fungi and their effects on germinating seeds and seedlings. The seeds were categorized into apparently healthy seeds, black point seeds, and shriveled and undersized seeds. Variation in different parameters (viz.Grading, weight, purity percentage, germination and seedling growth) became evident among the varieties. Seed health test on blotters and agar plate method showed that the major fungi associated with healthy seeds and black point seeds were Alternaria alternata, A. triticina, Bipolaris sorokiniana, B. tetramera, Curvularia lunata, Fusarium spp., and species of Aspergillus. The incidence of B. sorokiniana increased with increasing severity of black point infection. Reduction in germination, seedling emergence, plant stand, root and shoot growth, and vigor index were directly related with the severity of black point. Aspergillus spp. were seen more frequently associated with non-germinated seeds. J. Biodivers. Conserv. Bioresour. Manag. 2022, 8(1): 33-48

A comparative study on the antifungal efficacy of cold atmospheric plasma at low and high surface density on Aspergillus chevalieri and mechanisms of action

Cold atmospheric plasma (CAP) is a promising innovative technology for microbial inactivation on food surfaces. In this study, we evaluated the potential of CAP at low (CAP-O3) and high (CAP-NOx) power using Aspergillus chevalieri as a fungal model, one of the most xerophilic and xerotolerant molds causing food spoilage, We observed a strong reduction in mycelial growth (60%) and conidial germination (90%) after 30 min of CAP-NOx, while CAP-O3 was less effective showing no reduction in mycelia growth and only 36% of spore germination reduction. Furthermore, cell death was accompanied by a loss of cellular and mitochondrial potential membrane, a significant (p < 0.05) increase in intracellular ROS, RNS, calcium, and DNA damage. For the first time, we reported that trehalose, glycerol, chitin and glucan accumulation are some adaptive mechanisms of A. chevalieri to counteract CAP stress, with CAP-NOx treatments inducing a major accumulation of these two osmolites. Our results suggested that Cold atmospheric plasma-induced cell death can be explained by oxidative stress-dependent through a cascade of reactions initiated by membrane depolarization.

Seven years of white mold biocontrol product’s performance efficacy on Sclerotinia sclerotiorum carpogenic germination in Brazil: A meta-analysis

Biocontrol is a plausible strategy to be considered on the management of white mold but the efficacy is not always the same. Therefore, the identification of the sources of such variable performance fosters a fine-tune product recommendation to achieve the highest performance. Based on seven soybean crop seasons, 59 uniform field trials were conducted throughout Brazil to assess the performance of Sclerotinia sclerotiorum sclerotia parasitism under different temperature and rainfall regimes. Hence, we carried out a meta-analysis to evaluate the effect of three treatment classes (Trichoderma-, Bacillus-, and a Mixed combination of both organisms) on the reduction of S. sclerotiorum sclerotia carpogenic germination (mean difference; MD) according to a multilevel network model (59 trials, k = 340). Throughout trials included in the meta-analysis, biocontrol reduced carpogenic germination ca. 70 % of times, with fitted MD¯ values of − 10.6 for Bacillus, −8.6 for Trichoderma, and − 7.0 for Mixed Bacillus and Trichoderma groups. Separate network models were then fitted to determine the influence of average monthly temperature (AMT) and average monthly rainfall (AMR) under three classes (low, moderate, and high) for each variable on the carpogenic germination. Overall, interactions of treatments and low or moderate AMT and AMR were significant (p < 0.1). Temperatures above 27 °C and precipitation higher than 250 mm have not contributed to the reduction in carpogenic germination regardless of the considered active ingredient. Hence, biocontrol product́s reduce carpogenic germination in ca. 9 % and dominant weather conditions. These relationships are important factors involved in sclerotia colonization and therefore, high temperatures and rainfall should not be indicated for the product’s application for best BCAs performance.

Features of the preservation of rye genotypes in model conditions

Aim. The aim of the work was to establish the impact of rye seed storage in model conditions at seed moisture content of 5–7 % on germination indicators, productivity elements and plant height. Methods. The material for the research were seeds of rye accessions of different genotypes. The seeds used in the experiment were grown in the experimental fields of the Institute of Plant Production naned after V. Ya. Yuriev of NAAS (PPI), located in the northern forest-steppe of Ukraine. Laboratory germination was assessed according to the International Seed Testing Associations. Seeds after storage were sown in the experimental field of PPI during the growing seasons 2015/2016, 2016/2017, 2017/2018 in order to assess the elements of plant productivity. Indicators of temperature and precipitation of the period of seed growing have been recorded. Statistical processing of the obtained data was performed by standard methods using Excel. Results. It was found that after 12 months of storage of seeds of different genotypes in model conditions, significant changes in germination were observed only in isolated cases. After storing the seeds for 18 months, a significant reduction in germination was observed for all samples. Conclusions. Seeds of rye accessions with different genotypes in model conditions have different longevity. No significant benefits of seed moisture in the range of 5–7 % for its longevity. No significant stable impact of model storage conditions of experimental accessions of rye on plant height and elements of the structure of productivity in the year of research.

Comparing the effects of grain weathering and presence of fungal communities on waxy and non‐waxy sorghum hybrids grown across Texas

AbstractGrain weathering in grain sorghum [Sorghum bicolor (L.) Moench] is a persistent concern for producers in warm and humid climates. Further, grain sorghum genotypes are known to vary in their response to grain weathering; in some cases, this response is associated with a specific grain trait. For example, waxy endosperm sorghum is perceived to be more susceptible to grain weathering. This study herein compared waxy, heterozygous waxy, and non‐waxy sorghum hybrids grown in multiple environments for grain weathering susceptibility and characterization of the fungal communities on the grain. The traits used to evaluate grain weathering included first grain weathering rating (FGWR), area under the disease progress curve (AUDPC), initial germination (IG), and reduction in germination (RIG). Grain weathering intensity varied among the tested environments; increased weathering occurred with wetter conditions. In combined analyses, the environment accounted for more variation (70.2, 38.2, 39.9, and 81.1%) than did genotype (9.0, 26.9, 15.8, and 5.0%) for FGWR, AUDPC, IG, and RIG, respectively. In only one of the four environments were the waxy and heterozygous waxy hybrids statistically different from the non‐waxy genotypes. Ultimately, variation was more associated with genotypes than endosperm classes. Overall, Alternaria spp., Bipolaris spp., Fusarium semitectum, Curvularia spp., and Aspergillus niger were the most frequently observed pathogens across environments. Within an environment, the percent of different fungal pathogens remained relatively constant, but varied across environments. There was no clear distinction between either the level of grain weathering or the presence of a particular pathogen and endosperm type. The results indicate that grain sorghums with waxy endosperm are no more susceptible to grain weathering than those with normal, non‐waxy endosperm.

Bell pepper germination and seedling’s parameters under different osmotic potentials

Bell pepper (Capsicum annuum L.) is the third most cultivated Solanaceae species in Brazil and is highly sensitive to osmotic stresses. The increasing soil salinity is a frequent problem that hinders the plant absorption of water and nutrients by the roots, limiting agricultural production. Therefore, this study’s objectives were to evaluate the germination, vigor, and development of bell pepper commercial cultivars after NaCl treatments to simulate osmotic stress. Five cultivars (Yolo wonder, SF134 yellow, Marta, All big red, Cascadura) were submitted to four osmotic potentials (salt stresses of 0, -0.3, -0.6, -0.9 MPa) in a factorial scheme of 5×4, with four repetitions. The results indicated that the bell pepper germination is highly affected according to the presence of NaCl. The bell pepper germination supports NaCl concentrations equal to or higher than -0.3 MPa osmotic potential. Significant reductions in germination, germination speed index, seedling length, and dry mass as the salinity increases - osmotic potential decrease. The yellow bell pepper ‘SF134’ presented similar germination down to -0.6 MPa and can be cultivated in regions with salinity problems. The green bell pepper ‘Cascadura’ presented great germination, germination speed index and dry mass, and superior seedling length, being indicated for cultivation in more diverse environments.

Fungal endophyte Epicoccum nigrum 38L1 inhibits in vitro and in vivo the pathogenic fungus Fusarium graminearum

Wheat (Triticum aestivum L.) and its products constitute a major part of the daily human and animal diet. However, Fusarium head blight caused by Fusarium graminearum is one of the most devastating fungal diseases in wheat. In this study, a fungal endophyte strain 38L1 was newly isolated from leaf of maize (Zea mays L.) and identified as Epicoccum nigrum using molecular phylogenetic analysis of the rDNA internal transcribed spacer (ITS), large subunit ribosomal RNA (LSU) and beta-tubulin (TUB) gene sequences. In dual cultures and double plate assays, strain 38L1 markedly inhibited the mycelial growth of F. graminearum strain PH-1 and four other pathogenic fungi including Botrytis cinerea strain P-1, Colletotrichum gloeosporioides strain Y-3, Botrytis cinerea strain F-2, and Sclerotinia sclerotiorum strain D-4, indicating a broad antifungal activity. Besides, culture filtrates of strain 38L1 indicated a high fungicidal effect resulting in a significant reduction of mycelial growth, mycelial biomass and spore germination of F. graminearum strain PH-1. Furthermore, the application of conidial suspensions and/or culture filtrates of E. nigrum strain 38L1 with spore suspensions of F. graminearum strain PH-1 on wheat spikes resulted in a significant biocontrol efficacy of Fusarium head blight in growth chamber and field conditions. Hence, these results suggest that E. nigrum strain 38L1 could be a potential biocontrol agent against F. graminearum strain PH-1 in vitro and in vivo.

AtZAT4, a C2H2-Type Zinc Finger Transcription Factor from Arabidopsis thaliana, Is Involved in Pollen and Seed Development.

Pollen plays an essential role in plant fertility by delivering the male gametes to the embryo sac before double fertilization. In several plant species, including Arabidopsis, C2H2-type zinc-finger transcription factors (TFs) have been involved in different stages of pollen development and maturation. ZINC FINGER of Arabidopsis thaliana 4 (AtZAT4) is homologous to such TFs and subcellular localization analysis has revealed that AtZAT4 is located in the nucleus. Moreover, analysis of AtZAT4 expression revealed strong levels of it in flowers and siliques, suggesting a role of the encoded protein in the regulation of genes that are associated with reproductive development. We characterized a T-DNA insertional heterozygous mutant Atzat4 (+/−). The relative gene expression analysis of Atzat4 (+/−) showed significant transcript reductions in flowers and siliques. Furthermore, the Atzat4 (+/−) phenotypic characterization revealed defects in the male germline, showing a reduction in pollen tube germination and elongation. Atzat4 (+/−) presented reduced fertility, characterized by a smaller silique size compared to the wild type (WT), and a lower number of seeds per silique. Additionally, seeds displayed lower viability and germination. Altogether, our data suggest a role for AtZAT4 in fertilization and seed viability, through the regulation of gene expression associated with reproductive development.

Allelopathic Proclivities of &lt;i&gt;Simarouba glauca&lt;/i&gt; on Agricultural Crops

In this study, the allelochemicals present in the leachates of bark, fresh leaves, leaf litter and root of Simarouba glauca were identified using Gas Chromatography. The results revealed that the following allelochemicals viz. , benzoic acid, caffeic acid, catechol, coumaric acid, ferulic acid, resorcinol, salicylic acid and vanillic acid were present in the leachates. The bioassay of identified allelochemicals were tested on germination, seedling growth and vigour index of the following agricultural crops viz., blackgram, greengram, cowpea and redgram. The results reported that all the allelochemicals exhibited reduction in germination and growth of pulse crops. Among the allelochemicals, ferulic acid and salicylic acid exhibited maximum inhibitory effect on germination of the test crops at 1mM and 2mM concentrations respectively when compare to control. The maximum inhibitory effect on seedling growth and vigour index was registered by ferulic acid at both concentrations. Among the test crops, redgram was most affected and cowpea was least affected due to allelochemicals.

Hairy fleabane germination in response to temperature, osmotic potential, pH, salinity levels, and seed dormancy periods

AbstractHairy fleabane (Erigeron bonariensis L. Cronq.) is an invasive weed in low‐disturbance annual, perennial, and noncrop systems in the San Joaquin Valley (SJV), California. It is often observed emerging year‐round in diverse environmental conditions in the SJV. However, very little information is available on the reasons for this. The study aimed to assess the effect of temperature, water potential, salinity, pH level, and dormancy periods on hairy fleabane's germination. Tests were conducted at different day/night temperatures (5:0, 10:5, 15:10, 20:15, 25:20, and 30:25 °C), water potential (0 to –5.56 MPa), salinity (0–25 dS m–1), and pH (5–9). Germination tests were also performed on seeds the day they were collected from mature plants, and 7, 14, and 21 d later. Tests were conducted in growth chambers set to 20 °C or under ambient laboratory conditions at 22 °C. About 1% of the seeds germinated at 5 °C but maximum germination occurred at 25:20 °C. About 9% of the seeds germinated at –0.51 MPa and the estimated value for 50% germination reduction was –0.2 MPa. Seed germination had high tolerance to salinity, as 42% of the seeds germinated at 15 dS m–1. Germination did not differ across pH levels. About 50% of the seeds germinated the day they were collected, indicating that this species had a very short seed dormancy requirement. These findings could explain why hairy fleabane is observed emerging year‐round in the SJV, particularly in irrigated cropping systems.

Phytotoxicity evaluation of poly (ɛ-caprolactone) nanocapsules prepared using different methods and compositions in Brassica juncea seeds

The objective of this study was to analyze the phytotoxic effects of poly (ɛ-caprolactone) (PCL) nanocapsules on mustard ( Brassica juncea ) seeds. The nanoformulations were prepared using two protocols: PCL nanocapsules containing Tween as a stabilizer (NC TW) and PCL nanocapsules containing poly(vinyl alcohol) (PVA), a polymer that has emulsifying properties (NC PVA). Two experimental systems were used (nanoformulations sprayed on the substrate and as seed treatment), each one in a factorial scheme with two formulations (NC TW and NC PVA) and five dilutions (0%, 25%, 50%, 75%, and 100% of the stock formulation). In general, intermediary concentrations of NC TW showed higher phytotoxicity than NC PVA, as indicated by sharper reductions in germination and increases in the percentage of abnormal seedlings. However, in the substrate treatment, NC PVA (100%) led to a sharper reduction in germination than NC TW in the same dilution. NC TW-treated seeds presented greater water absorption. In an additional assay with nanocapsules labeled with a fluorescent probe (rhodamine B), NC PVA-treated seeds showed higher fluorescence intensity in the seed coat. In the case of NC TW-treated seeds, the fluorescence signal tended to move to the seed interior as the nanocapsule levels increased. Moreover, the seed treatment with this formulation induced sharper increases in water uptake by the seeds than NC PVA. The different effects induced by NC TW and NC PVA could be related to the different characteristics of the nanocapsules, as the lower size and more negative charge of NC TW might have favored their entrance into the seeds. • The nanocapsules led to some negative effects on seed germination. • They did not affect shoot and root length of mustard seedlings. • The nanocapsules altered the water uptake by the seeds. • The effects were dependent on the nanocapsules’ characteristics. • The effects were relatively low given the potential benefits of nanoencapsulation.

Response of Physiological, Reproductive Function and Yield Traits in Cultivated Chickpea (Cicer arietinum L.) Under Heat Stress.

Under global climate change, high-temperature stress is becoming a major threat to crop yields, adversely affecting plant growth, and ultimately resulting in significant yield losses in various crops, including chickpea. Thus, identifying crop genotypes with increased heat stress (HS) tolerance is becoming a priority for chickpea research. Here, we assessed the response of seven physiological traits and four yield and yield-related traits in 39 chickpea genotypes grown in normal-sown and late-sown environments [to expose plants to HS (>32/20°C) at the reproductive stage] for two consecutive years (2017–2018 and 2018–2019). Significant genetic variability for the tested traits occurred under normal and HS conditions in both years. Based on the tested physiological parameters and yield-related traits, GNG2171, GNG1969, GNG1488, PantG186, CSJ515, RSG888, RSG945, RVG202, and GNG469 were identified as promising genotypes under HS. Further, ten heat-tolerant and ten heat-sensitive lines from the set of 39 genotypes were validated for their heat tolerance (32/20°C from flowering to maturity) in a controlled environment of a growth chamber. Of the ten heat-tolerant genotypes, GNG1969, GNG1488, PantG186, RSG888, CSJ315, and GNG1499 exhibited high heat tolerance evidenced by small reductions in pollen viability, pollen germination, and pod set %, high seed yield plant–1 and less damage to membranes, photosynthetic ability, leaf water status, and oxidative processes. In growth chamber, chlorophyll, photosynthetic efficiency, pollen germination, and pollen viability correlated strongly with yield traits. Thus, GNG1969, GNG1488, PantG186, RSG888, CSJ315, and GNG1499 genotypes could be used as candidate donors for transferring heat tolerance traits to high-yielding heat-sensitive varieties to develop heat-resilient chickpea cultivars.

Effect of soil solarization and organic amendments on Sclerotium rolfsii Sacc sclerotia

Soil-borne pathogen Sclerotium rolfsii Sacc attacks several crops in Morocco. Studies were initiated to assess the potential of soil solarization, alone or combined with two organic amendments, namely compost and sheep manure, on the viability of S. rolfsii sclerotia. In the 4 and 6 weeks microplots experiment the highest soil temperature recorded was 59.3 °C in the solarized plots. Treatments from solarized plots with compost was significantly (p < 0.05) reduced germination and viability of sclerotia than other treatments, with a germination reduction rate of sclerotia (GRRS) of 100%, 93.4% and 53.6% at 5, 10 and 20 cm soil depth respectively. The field trial lasted 2 months and the germination rate of sclerotia (GRS) of plots solarized with compost, with sheep manure and those non-solarized/non-amended was 10.25%, 15.38% and 80.19% respectively. The results suggest that soil solarization combined with organic amendments proves to be effective in the control of S. rolfsii.

Biosynthesis and characterization of silver nanoparticles prepared using seeds of Sisymbrium irio and evaluation of their antifungal and cytotoxic activities

Abstract Recent studies have shown that green synthesis of silver nanoparticles (AgNPs) and their application in the control of phytopathogenic fungi is a burgeoning field. Sisymbrium irio (Si) (London rocket) is a well-known weed that grows abundantly in Saudi Arabia from February to May. The present study is concerned with the rapid synthesis of silver nanoparticles from the aqueous seed extract of Si) in the presence of sunlight. The biosynthesized Si-AgNPs were characterized using UV-Visible spectroscopy (UV-Vis), energy dispersive X-ray (EDX) microanalysis, dynamic light scattering analysis (DLS), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy analysis (FTIR). The UV-Vis spectrum revealed a prominent surface plasmon resonance (SPR) absorption band (∼439 nm) characteristic of AgNPs. As revealed by TEM analysis, the Si-AgNPs were predominantly spheroidal in shape and measured between 4 and 51 nm, while the Z average of nanoparticles was 94.81 nm as revealed by the DLS spectrum. The FTIR spectrum displayed peaks related to important functional groups (amines, phenols, carboxylic acids, flavonoids, aromatic compounds, and esters) that aid in the reduction, encapsulation, and stability of AgNPs. The Si-AgNPs were further investigated against a panel of potent fungal phytopathogens that included Alternaria alternata, A. brassicae, Fusarium solani, F. oxysporum, and Trichoderma harzianum. The cytotoxic activity of the biosynthesized nanoparticles against human cervical cancer cell lines (HeLa) was also tested. Si-AgNPs at 80 µg·mL−1 demonstrated a marked reduction in mycelial growth and spore germination. Similarly, Si-AgNPs exhibited dose-dependent cytotoxic activity against the HeLa cell line, with an IC50 value of 21.83 ± 0.76 µg·mL−1. The results of the present study demonstrate the robust cytotoxic and antifungal activities of Si-AgNPs. Based on the findings, Si-AgNPs can be exploited to design formulations that can effectively act as anticancer agents, controlling the proliferation of cancer cells while also combating fungal phytopathogens. However, future research to understand their toxicity mechanisms is needed.

First Report of the Biosynthesis and Characterization of Silver Nanoparticles Using Scabiosa atropurpurea subsp. maritima Fruit Extracts and Their Antioxidant, Antimicrobial and Cytotoxic Properties.

Candida and dermatophyte infections are difficult to treat due to increasing antifungal drugs resistance such as fluconazole, as well as the emergence of multi-resistance in clinical bacteria. Here, we first synthesized silver nanoparticles using aqueous fruit extracts from Scabiosa atropurpurea subsp. maritima (L.). The characterization of the AgNPs by means of UV, XRD, FTIR, and TEM showed that the AgNPs had a uniform spherical shape with average sizes of 40–50 nm. The biosynthesized AgNPs showed high antioxidant activity when investigated using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. The AgNPs displayed strong antibacterial potential expressed by the maximum zone inhibition and the lowest MIC and MBC values. The AgNPs revealed a significant antifungal effect against the growth and biofilm of Candida species. In fact, the AgNPs were efficient against Trichophyton rubrum, Trichophyton interdigitale, and Microsporum canis. The antifungal mechanisms of action of the AgNPs seem to be due to the disruption of membrane integrity and a reduction in virulence factors (biofilm and hyphae formation and a reduction in germination). Finally, the silver nanoparticles also showed important cytotoxic activity against the human multiple myeloma U266 cell line and the human breast cancer cell line MDA-MB-231. Therefore, we describe new silver nanoparticles with promising biomedical application in the development of novel antimicrobial and anticancer agents.

In vitro effect of cocoa leachates on growth and development of Moniliophthora roreri ([Cif.] H.C. Evans et al.) isolated from Theobroma cacao (L.)

The cocoa crop is part of the peasant’s economic activity and agroforestry systems in many regions of Colombia and the world. Its yields are diminished by phytosanitary problems, being the frosty pod rot caused by the fungus Moniliophthora roreri, the most limiting disease with decreases in production of over 90%. In this study, samples of cocoa leachates from commercial producing farms were characterized and the antifungal activity of sterilized, non-sterilized, and filtered cocoa leachates against M. roreri was evaluated under in vitro conditions, at concentrations of 1, 2, 5, 10, and 15%. Monosporic isolates of the pathogen were obtained from diseased fruits collected from cocoa-producing farms in the municipality of Yacopi in Cundinamarca, Colombia. The effect of leachates on M. roreri conidial germination, mycelial growth, and inoculum production was evaluated. It was found that non-sterilized cocoa leachates at all concentrations caused 100% reduction on the three variables evaluated, while sterilized leachates generated the same effect at concentrations of 10 and 15%. Filtered leachates showed no inhibitory effect on the radial growth of the pathogen, but they caused a reduction of conidial germination of 89.9, 90.5 and 95.9% at concentrations of 5, 10, and 15%. The presence of malic, citric, and ascorbic acids, compounds such as NH4, PO4, and NO3, and elements such as Ca, K, Na, Mg, and Cl in the evaluated leachates was identified using high-efficiency liquid chromatography and physicochemical analysis. This research showed the potential of cocoa leachates, even at low concentrations, for the control of M. roreri, which can be attributed to the action of specific compounds such as those found in chromatographic tests.