IoT for Monitoring Fungal Growth and Ochratoxin A Development in Grapes Solar Drying in Tunnel and in Open Air

Optimisation of solar drying to reduce fungal growth and Ochratoxin A (OTA) contamination is a crucial concern in raisin and currant production. Stochastic and deterministic analysis has been utilized to investigate environmental indicators and drying characteristics. The analysis was performed using two seedless grape varieties (Crimson—red and Thompson—white) that were artificially inoculated with Aspergillus carbonarius during open-air and tunnel drying. Air temperature (T) and relative humidity (RH) were measured and analysed during the drying experiment, along with grape surface temperature (Ts), and water activity (aw). The grape moisture content, fungal colonization, and OTA contamination were estimated, along with the water diffusivity (Deff) and peel resistance (rpeel) to water transfer. Monitoring the surface temperature of grapes is essential in the early detection of fungal growth and OTA contamination. As surface temperature should be carried out continuously, remote sensing protocols, such as infrared sensors, provide the most efficient means to achieve this. Furthermore, data collection and analysis could be conducted through the Internet of Things (IoT), thereby enabling effortless accessibility. The average Ts of the grapes was 6.5% higher in the tunnel than in the open-air drying. The difference between the RH of air and that in the plastic crates was 16.26–17.22%. In terms of CFU/mL, comparison between white and red grapes in the 2020 and 2021 experiments showed that the red grapes exhibited significantly higher values than the white grapes. Specifically, the values for red grapes were 4.3 in 2021 to 3.4 times in 2020 higher compared to the white grapes. On the basis of the conducted analysis, it was concluded that tunnel drying provided some advantages over open-air drying, provided that hygienic and managerial requirements are met

Reduction of Mycotoxigenic Fungi Growth and Their Mycotoxin Production by Bacillus subtilis QST 713

The use of chemical pesticides to control the occurrence of mycotoxigenic fungi in crops has led to environmental and human health issues, driving the agriculture sector to a more sustainable system. Biocontrol agents such as Bacillus strains and their antimicrobial metabolites have been proposed as alternatives to chemical pesticides. In the present work, a broth obtained from a commercial product containing Bacillus subtilis QST 713 was tested for its ability to inhibit the growth of mycotoxigenic fungi as well as reduce their mycotoxin production. Mass spectrometry analysis of Bacillus subtilis broth allowed to detect the presence of 14 different lipopeptides, belonging to the iturin, fengycin, and surfactin families, already known for their antifungal properties. Bacillus subtilis broth demonstrated to be a useful tool to inhibit the growth of some of the most important mycotoxigenic fungi such as Aspergillus flavus, Fusarium verticillioides, Fusarium graminearum, Aspergillus carbonarius, and Alternaria alternata. In addition, cell-free Bacillus subtilis broth provided the most promising results against the growth of Fusarium graminearum and Alternaria alternata, where the radial growth was reduced up to 86% with respect to the untreated test. With regard to the mycotoxin reduction, raw Bacillus subtilis broth completely inhibited the production of aflatoxin B1, deoxynivalenol, zearalenone, and tenuazonic acid. Cell-free broth provided promising inhibitory properties toward all of the target mycotoxins, even if the results were less promising than the corresponding raw broth. In conclusion, this work showed that a commercial Bacillus subtilis, characterized by the presence of different lipopeptides, was able to reduce the growth of the main mycotoxigenic fungi and inhibit the production of related mycotoxins

Aspergillus flavus and Fusarium verticillioides interaction: modeling the impact on mycotoxin production.

The influence of climate change on agricultural systems has been generally accepted as having a considerable impact on food security and safety. It is believed that the occurrence of mycotoxins will be greatly affected by future climate scenarios and this has been confirmed by recent data. Temperature (T) and CO2 increases, variation in rain intensity and distribution, as well as extreme weather events, affect the dominant fungal species in different ways, depending on their ecological needs. Therefore, the aim of this work was to study Aspergillus flavus (Af) and Fusarium verticillioides (Fv) co-occurrence in vitro in order to collect quantitative data on the effect of fungal interaction on growth and mycotoxin production and develop functions for their description. Experimental trials were organized with the cited fungi grown alone or together. They were incubated at different T regimes (10\u201340\ub0C, step 5\ub0C) for 21 days. Fungal growth was measured weekly, while AFs and FBs were quantified at the end of the incubation period. Temperature and incubation time significantly affected fungal growth both for Af and Fv (p 64 0.01), and a significant interaction between T and the presence of one versus both fungi influenced the amount of AFs and FBs produced. Each fungus was affected by the presence of the other fungus; in particular, Af and Fv showed a decrease in colony diameter of 10 and 44%, respectively, when they were grown together, compared to alone. The same influence was not found for mycotoxin production. In fact, the dynamics of toxin production in different temperature regimes followed a comparable trend with fungi grown alone or together, but a significant impact of inoculum 7 temperature interaction was highlighted. Fungal growth and toxin production in different T regimes were well described, both for AFs and FBs, by a Bete function. These results are the first attempt to model mycotoxigenic fungal co-occurrence under several T regimes; this is essential in order to improve effective prediction of growth and mycotoxin production by such fungi

TEMPERATURE AND LEVEL DENSITY PARAMETER OF EVAPORATION RESIDUES PRODUCED IN THE REACTION 165Ho + 600 MeV 20Ne

Evaporative and preequilibrium neutrons emitted from evaporation residues in the reaction Ho + 600 MeV neon are exploited to deduce the thermal excitation energy E* and temperature T of the residues. From these quantities the level density parameter is deduced at a temperature of 4.1 MeV

TRANSCRIPTIONAL ANALYSIS OF EIGHT MAGIC MAIZE PARENTAL LINES INFECTED WITH FUSARIUM VERTICILLIOIDES

Maize (Zea mays L.) is among the most important crops worldwide for food, feed, biofuels, and industrial applications. Its cultivation faces significant constraints due to Fusarium species that affect the quality and quantity of maize products. Among these, Fusarium verticillioides is responsible for severe diseases including seedling blights, stalk rot, and ear rot. The impact of the fungus is worsened by the fact that chemical and agronomic measures used to control Fusarium infection are often inefficient. Hence, genetic resistance is considered the most reliable resource to reduce damages caused by F. verticillioides. This study aims to elucidate the genetic basis of resistance to this fungus in maize. Young seedlings of eight divergent maize lines, founder of the MAGIC population, were artificially inoculated with a F. verticillioides strain using the rolled towel assay method. Total RNA was extracted from both control and treated samples after 72 hours of artificial inoculation and underwent paired-end sequenced with Illumina technology. Here we report the use this large transcriptomic dataset to identify the early transcriptional changes and the differentially expressed genes (DEGs) involved in fungal infection. The analysis identified several hundred DEGs, whose functions were explored through Gene Ontology enrichment analysis. A co-expression network analysis further refined the set of genes with potential implications in disease response. The results identify a limited set of genes that might play an important roles in maize resistance to F. verticillioides providing new insights into the molecular resistance mechanisms against the pathogen

Room temperature single-photon sources based on single colloidal nanocrystals in microcavities

Abstract Direct lithography of resist blends, embedding semiconductor colloidal nanocrystals (NCs) is an innovative way to achieve nanopositioning of NCs in quantum-confined optical resonators. In this work, we show a new appealing approach for the fabrication of single-photon sources operating at room temperature by localizing semiconductor colloidal NCs into vertical planar microcavities with lithographic techniques

Fusarium verticillioides and aspergillus flavus co-occurrence influences plant and fungal transcriptional profiles in maize kernels and in vitro

Climate change will increase the co-occurrence of Fusarium verticillioides and Aspergillus flavus, along with their mycotoxins, in European maize. In this study, the expression profiles of two pathogenesis-related (PR) genes and four mycotoxin biosynthetic genes, FUM1 and FUM13, fumonisin pathway, and aflR and aflD, aflatoxin pathway, as well as mycotoxin production, were examined in kernels and in artificial medium after a single inoculation with F. verticillioides or A. flavus or with the two fungi in combination. Different temperature regimes (20, 25 and 30◦ C) over a time-course of 21 days were also considered. In maize kernels, PR genes showed the strongest induction at 25◦ C in the earlier days post inoculation (dpi)with both fungi inoculated singularly. A similar behaviour was maintained with fungi co-occurrence, but with enhanced defence response at 9 dpi under 20◦ C. Regarding FUM genes, in the kernels inoculated with F. verticillioides the maximal transcript levels occurred at 6 dpi at 25◦ C. At this temperature regime, expression values decreased with the co-occurrence of A. flavus, where the highest gene induction was detected at 20◦ C. Similar results were observed in fungi grown in vitro, whilst A. flavus presence determined lower levels of expression along the entire time-course. As concerns afl genes, considering both A. flavus alone and in combination, the most elevated transcript accumulation occurred at 30◦ C during all time-course both in infected kernels and in fungi grown in vitro. Regarding mycotoxin production, no significant differences were found among temperatures for kernel contamination, whereas in vitro the highest production was registered at 25◦ C for aflatoxin B1 and at 20◦ C for fumonisins in the case of single inoculation. In fungal co-occurrence, both mycotoxins resulted reduced at all the temperatures considered compared to the amount produced with single inoculation

Functional Study of Lipoxygenase-Mediated Resistance against Fusarium verticillioides and Aspergillus flavus Infection in Maize

Mycotoxin contamination of maize kernels by fungal pathogens like Fusarium verticillioides and Aspergillus flavus is a chronic global challenge impacting food and feed security, health, and trade. Maize lipoxygenase genes (ZmLOXs) synthetize oxylipins that play defense roles and govern host-fungal interactions. The current study investigated the involvement of ZmLOXs in maize resistance against these two fungi. A considerable intraspecific genetic and transcript variability of the ZmLOX family was highlighted by in silico analysis comparing publicly available maize pan-genomes and pan-transcriptomes, respectively. Then, phenotyping and expression analysis of ZmLOX genes along with key genes involved in oxylipin biosynthesis were carried out in a maize mutant carrying a Mu transposon insertion in the ZmLOX4 gene (named UFMulox4) together with Tzi18, Mo17, and W22 inbred lines at 3- and 7-days post-inoculation with F. verticillioides and A. flavus. Tzi18 showed the highest resistance to the pathogens coupled with the lowest mycotoxin accumulation, while UFMulox4 was highly susceptible to both pathogens with the most elevated mycotoxin content. F. verticillioides inoculation determined a stronger induction of ZmLOXs and maize allene oxide synthase genes as compared to A. flavus. Additionally, oxylipin analysis revealed prevalent linoleic (18:2) peroxidation by 9-LOXs, the accumulation of 10-oxo-11-phytoenoic acid (10-OPEA), and triglyceride peroxidation only in F. verticillioides inoculated kernels of resistant genotypes

Loss of zmlipoxygenase4 decreases fusarium verticillioides resistance in maize seedlings

Fusarium verticillioides is one of the most relevant fungal species in maize responsible for ear, stalk and seedling rot, as well as the fumonisin contamination of kernels. Plant lipoxygenases (LOX) synthesize oxylipins that play a crucial role in the regulation of defense mechanisms against pathogens and influence the outcome of pathogenesis. To better uncover the role of these signaling molecules in maize resistance against F. verticillioides, the functional characterization of the 9\u2010LOX gene, ZmLOX4, was carried out in this study by employing mutants carrying Mu insertions in this gene (named as UFMulox4). In this regard, the genotyping of five UFMulox4 identified the mutant UFMu10924 as the only one having an insertion in the coding region of the gene. The impact of ZmLOX4 mutagenesis on kernel defense against F. verticillioides and fumonisin accumulation were investigated, resulting in an increased fungal susceptibility compared to the inbred lines W22 and Tzi18. Moreover, the expression of most of the genes involved in the LOX, jasmonic acid (JA) and green leaf volatiles (GLV) pathways, as well as LOX enzymatic activity, decreased or were unaffected by fungal inoculation in the mutant UFMu10924. These results confirm the strategic role of ZmLOX4 in controlling defense against F. verticillioides and its influence on the expression of several LOX, JA and GLV genes

Enhancing plant defense using rhizobacteria in processing tomatoes: a bioprospecting approach to overcoming Early Blight and Alternaria toxins

Plant growth-promoting rhizobacteria (PGPR) with antagonistic activity toward plant pathogenic fungi are valuable candidates for the development of novel plant protection products based on biocontrol activity. The very first step in the formulation of such products is to screen the potential effectiveness of the selected microorganism(s). In this study, non-pathogenic rhizobacteria were isolated from the rhizosphere of tomato plants and evaluated for their biocontrol activity against three species of mycotoxin-producing Alternaria. The assessment of their biocontrol potential involved investigating both fungal biomass and Alternaria toxin reduction. A ranking system developed allowed for the identification of the 12 best-performing strains among the initial 85 isolates. Several rhizobacteria showed a significant reduction in fungal biomass (up to 76%) and/or mycotoxin production (up to 99.7%). Moreover, the same isolates also demonstrated plant growth-promoting (PGP) traits such as siderophore or IAA production, inorganic phosphate solubilization, and nitrogen fixation, confirming the multifaceted properties of PGPRs. Bacillus species, particularly B. amyloliquefaciens and two strains of B. subtilis, showed the highest efficacy in reducing fungal biomass and were also effective in lowering mycotoxin production. Isolates such as Enterobacter ludwigii, Enterobacter asburiae, Serratia nematodiphila, Pantoea agglomerans, and Kosakonia cowanii showed moderate efficacy. Results suggest that by leveraging the diverse capabilities of different microbial strains, a consortium-based approach would provide a broader spectrum of effectiveness, thereby signaling a more encouraging resolution for sustainable agriculture and addressing the multifaceted nature of crop-related biotic challenges