Patterns of herbicide resistance in Raphanus raphanistrum revealed by comprehensive testing and statistical analysis.

BACKGROUND: Raphanus raphanistrum causes $40 million total revenue losses annually in Western Australia partly due to its historically-documented ability to evolve herbicide resistance to multiple modes of action. In this study, 376 field-sampled populations of R. raphanistrum were tested for resistance to 21 herbicides applied at the recommended label rate. Eight treatments were herbicide mixtures with two, three or four modes of action. RESULTS: A total of 7199 individual resistance tests were conducted across 4 years by screening approximately 104 000 individual seeds and seedlings. The mean survival of individuals within a population for all standalone herbicides was 9%, whereas survival was significantly decreased to 3.5% with a herbicide mixture. Some herbicides such as triasulfuron (herbicide Group 2), 2,4-D (Group 4) or diflufenican (Group 12) were highly impacted by resistance, with frequencies of resistant populations being > 50%. Conversely, there was negligible resistance to glyphosate (Group 9) or protoporphyrinogen oxidase (PPO) inhibitors (tiafenacil, saflufenacil + trifludimoxazin, fomesafen: Group 14), and pre-emergence herbicides (i.e., atrazine or mesotrione: Groups 5 and 27, respectively) remained largely effective. Binary, ternary or quaternary mixtures of Groups 4, 6, 12 and 27 herbicides reduced the frequency of high-level resistant populations to 7.1%, 3.8% or 0%, respectively. CONCLUSIONS: The cost-effective control of R. raphanistrum remains a challenge due to herbicide resistance. Raphanus raphanistrum management relies heavily on herbicide uses not yet compromised by resistance, such as pre-emergence herbicides (atrazine, fomesafen, mesotrione), glyphosate, and mixtures of two, three or four modes of action including bromoxynil, diflufenican, MCPA, picolinafen, pyrasulfotole and topramezone. Strategies that integrate effective herbicide use patterns, novel modes of action and efficiently-mechanized non-chemical weed control options (i.e., seed destructors) can completely constrain the selection of herbicide resistance in this highly adaptable species. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Crop rotational diversity can mitigate climate-induced grain yield losses.

Diversified crop rotations have been suggested to reduce grain yield losses from the adverse climatic conditions increasingly common under climate change. Nevertheless, the potential for climate change adaptation of different crop rotational diversity (CRD) remains undetermined. We quantified how climatic conditions affect small grain and maize yields under different CRDs in 32 long-term (10-63 years) field experiments across Europe and North America. Species-diverse and functionally rich rotations more than compensated yield losses from anomalous warm conditions, long and warm dry spells, as well as from anomalous wet (for small grains) or dry (for maize) conditions. Adding a single functional group or crop species to monocultures counteracted yield losses from substantial changes in climatic conditions. The benefits of a further increase in CRD are comparable with those of improved climatic conditions. For instance, the maize yield benefits of adding three crop species to monocultures under detrimental climatic conditions exceeded the average yield of monocultures by up to 553 kg/ha under non-detrimental climatic conditions. Increased crop functional richness improved yields under high temperature, irrespective of precipitation. Conversely, yield benefits peaked at between two and four crop species in the rotation, depending on climatic conditions and crop, and declined at higher species diversity. Thus, crop species diversity could be adjusted to maximize yield benefits. Diversifying rotations with functionally distinct crops is an adaptation of cropping systems to global warming and changes in precipitation.

Silver nanoclusters with Ag2+/3+ oxidative states are a new highly effective tool against phytopathogenic bacteria.

The main measure worldwide adopted to manage plant bacterial diseases is based on the application of copper compounds, which are often partially efficacious for the frequent appearance of copper-resistant bacterial strains and have raised concerns for their toxicity to the environment and humans. Therefore, there is an increasing need to develop new environmentally friendly, efficient, and reliable strategies for controlling plant bacterial diseases, and among them, the use of nanoparticles seems promising. The present study aimed to evaluate the feasibility of protecting plants against attacks of gram-negative and gram-positive phytopathogenic bacteria by using electrochemically synthesized silver ultra nanoclusters (ARGIRIUM­SUNCs®) with an average size of 1.79 nm and characterized by rare oxidative states (Ag2+/3+). ARGIRIUM­SUNCs strongly inhibited the in vitro growth (effective concentration, EC50, less than 1 ppm) and biofilm formation of Pseudomonas syringae pv. tomato and of quarantine bacteria Xanthomonas vesicatoria, Xylella fastidiosa subsp. pauca, and Clavibacter michiganensis subsp. michiganensis. In addition, treatments with ARGIRIUM­SUNCs also provoked the eradication of biofilm for P. syringae pv. tomato, X. vesicatoria, and C. michiganensis subsp. michiganensis. Treatment of tomato plants via root absorption with ARGIRIUM­SUNCs (10 ppm) is not phytotoxic and protected (80%) the plants against P. syringae pv. tomato attacks. ARGIRIUM­SUNCs at low doses induced hormetic effects on P. syringae pv. tomato, X. vesicatoria, and C. michiganensis subsp. michiganensis as well as on tomato root growth. The use of ARGIRIUM­SUNCs in protecting plants against phytopathogenic bacteria is a possible alternative control measure. KEY POINTS: • ARGIRIUM­SUNC has strong antimicrobial activities against phytopathogenic bacteria; • ARGIRIUM­SUNC inhibits biofilm formation at low doses; • ARGIRIUM­SUNC protects tomato plants against bacterial speck disease.

Marketed Quinoa (Chenopodium quinoa Willd.) Seeds: A Mycotoxin-Free Matrix Contaminated by Mycotoxigenic Fungi.

A total of 25 marketed quinoa seed samples different for origin, farming system and packaging were analyzed for the presence of mycotoxigenic fungi (by isolation both on Potato Dextrose Agar and with the deep-freezing blotter method) and relative contamination by mycotoxins (by LC-MS/MS analysis). Fungal microorganisms, but not mycotoxins, were detected in all the samples, and 25 isolates representative of the mycobiota were obtained. Morphological and molecular characterization and, for some isolates, the in vitro mycotoxigenic profile, allowed the identification of 19 fungal species within five different genera: Alternaria, Aspergillus, Penicillium, Cladosporium and Fusarium. Among the identified species, Alternaria abundans, A. chartarum, A. arborescens, Cladosporium allicinum, C. parasubtilissimum, C. pseudocladosporioides, C. uwebraunianum, Aspergillus jensenii, A. tubingensis, Penicillium dipodomyis, P. verrucosum and P. citreosulfuratum were first reported on quinoa, and Alternaria infectoria and Fusarium oxysporum were first reported on quinoa seeds. The geographical origin, farming system and packaging were showed to affect the amount and type of the isolated fungal species, highlighting that the level of fungal presence and their related secondary metabolites is conditioned by different steps of the quinoa supply chain. However, despite the presence of mycotoxigenic fungi, the marketed quinoa seeds analyzed resulted in being free from mycotoxins.

Different diagnostic approaches for the characterization of the fungal community and Fusarium species complex composition of Italian durum wheat grain and correlation with secondary metabolite accumulation.

BACKGROUND: The evolution of the fungal communities associated with durum wheat was assessed using different diagnostic approaches. Durum wheat grain samples were collected in three different Italian cultivation macro-areas (north, center and south). Fungal isolation was realized by potato dextrose agar (PDA) and by deep-freezing blotter (DFB). Identification of Fusarium isolates obtained from PDA was achieved by partial tef1α sequencing (PDA + tef1α), while those obtained from DFB were identified from their morphological characteristics (DFB + mc). The fungal biomass of eight Fusarium species was quantified in grains by quantitative polymerase chain reaction (qPCR). Fungal secondary metabolites were analyzed in grains by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Correlations between Fusarium detection techniques (PDA + tef1α; DFB + mc and qPCR) and mycotoxins in grains were assessed. RESULTS: Alternaria and Fusarium showed the highest incidence among the fungal genera developed from grains. Within the Fusarium community, PDA + tef1α highlighted that F. avenaceum and F. graminearum were the most represented members, while, DFB + mc detected a high presence of F. proliferatum. Alternaria and Fusarium mycotoxins, principally enniatins, were particularly present in the grain harvested in central Italy. Deoxynivalenol was mainly detected in northern-central Italy. CONCLUSIONS: The adoption of the different diagnostic techniques of Fusarium detection highlighted that, for some species, qPCR was the best method of predicting their mycotoxin contamination in grains. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

An integrated approach for the characterization of wild Crocus species adopting phenotypical and phytochemical traits.

Crocus is a taxonomically complex genus, characterized by high intra- and inter-specific variability. Five wild Crocus taxa - Crocus biflorus, C. longiflorus, C. neapolitanus, C. siculus and C. thomasii from three different areas of Southern Italy (Calabria, Basilicata and Sicily) have been investigated. We considered both flower morphological traits (inner and outer perigone segments, style branches and anthers) and the chemical profile of specialised metabolites (apocarotenoids: crocins; flavonoids: flavonols) in style branches, which were determined by high-performance liquid chromatography, coupled with a diode array detector and mass spectrometry (HPLC-UV-DAD-ESI-MS). Saffron (C. sativus) was also included as the 'control' species. The length of perigone tube, outer and inner tepals, anthers and style branches gave the highest contribution to the discrimination of different taxa. Concerning the specialised metabolite profiles, 20 flavonols and 24 crocins have been identified and quantified in the Crocus extracts and used to discriminate among samples, confirming that Crocus taxa can be considered as an important natural source of these substances. The chemical profiles of the different populations showed some distinctive qualitative and quantitative patterns that contributed to a certain degree of discrimination among species, in fact, flavonoids content range is comprised between 2.7 and 145.9 mg/g, whereas crocins range between 19.8 and 604.0 mg/g. It is thus hypothesized that the combination of morphological and phytochemical screenings may be an effective methodology to characterize wild Crocus genotypes from Southern Italy, also in comparison to C. sativus (saffron).

Conditional Seed Dormancy Helps Silene hicesiae Brullo & Signor. Overcome Stressful Mediterranean Summer Conditions.

Investigations on seed biology and ecology are of major importance for the conservation of threatened plants, both providing baseline information and suggesting practical approaches. In our study, we focused on the germination behavior of Silene hicesiae Brullo & Signor., a narrow endemic species to Panarea and Alicudi (Aeolian Archipelago, Italy), as well as one of the 50 most threatened Mediterranean island plants. Specifically, the effects of temperature, light, seed age, seed source, and collection year were evaluated; in addition, threshold temperatures and thermal-time parameters were estimated. The thermal range for fresh seed germination resulted between 5 and 15 °C, reaching up to 20 and 25 °C at increasing seed age, with 30 °C being clearly beyond the ceiling temperature. This behavior indicates that fresh seeds exhibit the Type 1 non-deep physiological dormancy, and that germination is regulated by conditional dormancy. This dormancy syndrome emerged as a highly efficient adaptation strategy for this species and, together with thermo-inhibition, would allow seeds to counteract or take advantage of Mediterranean environmental conditions. The comparison between the wild Panarea population and the corresponding ex situ cultivated progeny has enabled the identification of the latter as a suitable seed source for sustainable in situ reinforcement actions, at least in the short-term; indeed, plant cultivation for a single generation did not produce significant modifications in the germination behavior of the offspring.

Improving Hunted Wild Boar Carcass Hygiene: Roles of Different Factors Involved in the Harvest Phase.

Game meat production strongly differs from that of other meats, as peculiar factors present in the field and in the steps prior to transfer to a game-handling establishment can influence the hygiene of the carcasses and, therefore, of the meat. The effects of such factors were considered in hunted wild boars based on the main hygienic criteria adopted in meat processing. Environmental, animal, and hunting conditions were studied during two selective hunting seasons in Central Italy. A total of 120 hunted wild boar carcasses were sampled after the skinning process and analyzed for aerobic colony count, Enterobacteriaceae count, and Salmonella spp. isolation. The calculated mean values for aerobic colony and Enterobacteriaceae counts were 3.66 and 2.05 CFU/cm2, respectively, in line with the limits set for the meat of other ungulates by EU legislation. Salmonella spp. showed a prevalence of 2.5% (IC 95%: 1.72-3.27%). Statistical analysis of the data performed with the AIC criterion showed that the main parameter to consider for improving the hygienic level of carcasses is to reduce the time in the refrigerator before skinning, followed by hunting on cold days (<10 °C) without rain, hunting animals <60 kg, and reducing the time between shooting and evisceration.

Synergistic interaction between the type III secretion system of the endophytic bacterium Pantoea agglomerans DAPP-PG 734 and the virulence of the causal agent of olive knot Pseudomonas savastanoi pv. savastanoi DAPP-PG 722.

The endophytic bacterium Pantoea agglomerans DAPP-PG 734 was previously isolated from olive knots caused by infection with Pseudomonas savastanoi pv. savastanoi DAPP-PG 722. Whole-genome analysis of this P. agglomerans strain revealed the presence of a Hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS). To assess the role of the P. agglomerans T3SS in the interaction with P. savastanoi pv. savastanoi, we generated independent knockout mutants in three Hrp genes of the P. agglomerans DAPP-PG 734 T3SS (hrpJ, hrpN, and hrpY). In contrast to the wildtype control, all three mutants failed to cause a hypersensitive response when infiltrated in tobacco leaves, suggesting that P. agglomerans T3SS is functional and injects effector proteins in plant cells. In contrast to P. savastanoi pv. savastanoi DAPP-PG 722, the wildtype strain P. agglomerans DAPP-PG 734 and its Hrp T3SS mutants did not cause olive knot disease in 1-year-old olive plants. Coinoculation of P. savastanoi pv. savastanoi with P. agglomerans wildtype strains did not significantly change the knot size, while the DAPP-PG 734 hrpY mutant induced a significant decrease in knot size, which could be complemented by providing hrpY on a plasmid. By epifluorescence microscopy and confocal laser scanning microscopy, we found that the localization patterns in knots were nonoverlapping for P. savastanoi pv. savastanoi and P. agglomerans when coinoculated. Our results suggest that suppression of olive plant defences mediated by the Hrp T3SS of P. agglomerans DAPP-PG 734 positively impacts the virulence of P. savastanoi pv. savastanoi DAPP-PG 722.

Herbicide resistance across the Australian continent.

BACKGROUND: Lolium rigidum is the weed of greatest economic impact in Australia due to its formidable capacity to evolve herbicide resistance. In this study, 579 field-sampled L. rigidum populations were tested for resistance to 21 herbicides applied at the recommended rate. Nine herbicide treatments were binary mixtures. RESULTS: A total of 15 876 individual resistance tests were conducted by screening two million seeds at the recommended label rate. The overall frequency of resistant populations was 31%, 14%, 71%, 6% and 0% in response to the post-emergence herbicide treatments clethodim, clethodim + butroxydim, imazamox + imazapyr, glyphosate and paraquat, respectively. The resistance frequency to stand-alone pre-emergence wheat-selective herbicides ranged from 10% to 34%. Conversely, the levels of resistance to pre-emergence mixtures or stand-alone propyzamide were significantly lower, ranging from 6% to 0%. In winter, the responses to glyphosate, paraquat, cinmethylin, prosulfocarb, pyroxasulfone and trifluralin were reassessed, with 7%, 0%, 0%, 21%, 21% and 28% as the respective resistance frequencies. South Australia and Victoria are identified as epicenters for L. rigidum population resistance to pyroxasulfone, whereas populations in New South Wales have the greatest resistance to glyphosate and in Western Australia to clethodim. CONCLUSIONS: For the first time, resistance levels to stand-alone herbicides and binary mixtures are geographically ranked across the Australian continent by benchmark statistical analysis of resistance frequencies and distribution. The extension of these results will raise awareness of rapidly emerging patterns of herbicide resistance, encouraging the adoption of cost-effective modes of action and integration of diverse strategies for weed resistance management.

Linear models for diallel crosses: a review with R functions.

KEY MESSAGE: A new R-software procedure for fixed/random Diallel models was developed. We eased the diallel schemes approach by considering them as specific cases with different parameterisations of a general linear model. Diallel experiments are based on a set of possible crosses between some homozygous (inbred) lines. For these experiments, six main diallel models are available in literature, to quantify genetic effects, such as general combining ability (GCA), specific combining ability (SCA), reciprocal (maternal) effects and heterosis. Those models tend to be presented as separate entities, to be fitted by using specialised software. In this manuscript, we reinforce the idea that diallel models should be better regarded as specific cases (different parameterisations) of a general linear model and might be fitted with general purpose software facilities, as used for all other types of linear models. We start from the estimation of fixed genetical effects within the R environment and try to bridge the gap between diallel models, linear models and ordinary least squares estimation (OLS). First, we review the main diallel models in literature. Second, we build a set of tools to enable geneticists, plant/animal breeders and students to fit diallel models by using the most widely known R functions for OLS fitting, i.e. the 'lm()' function and related methods. Here, we give three examples to show how diallel models can be built by using the typical process of GLMs and fitted, inspected and processed as all other types of linear models in R. Finally, we give a fourth example to show how our tools can be also used to fit random/mixed effect diallel models in the Bayesian framework.

Scion and Rootstock Differently Influence Growth, Yield and Quality Characteristics of Cherry Tomato.

Grafting is a valuable tool for managing problems of tomato soil-borne pathogens and pests, but often generates unpredictable effects on crop yield and product quality. To observe these rootstocks-induced changes, experimental designs including many rootstock-scion combinations are required. To this end, a greenhouse experiment was conducted on 63 graft combinations, involving seven cherry tomato scions grouped in large, medium and small-fruited, and eight rootstocks with different genetic backgrounds (crosses between Solanum lycopersicum and S. habrochaites or S. peruvianum or S. pimpinellifolium, plus an intraspecific hybrid), using ungrafted controls. The response of the graft partners was firstly analyzed individually using the environmental variance (σ2E), then by grouping them by classes. When analyzed individually, the scion genotype influenced fruit L*, b*, shape index, total soluble solids (TSS) and its ratio with tritatable acidity (TSS/TA), whereas plant growth and yield were unpredictable. After clustering the graft partners, some of these responses were attributable to the imposed classes. The S. habrochaites-derived hybrids maximized plant biomass, unlike the S. pimpinellifolium ones. Both classes reduced fruit biomass in small- and medium-fruited scions (by 11 and 14%, respectively). The S. habrochaites and S. peruvianum hybrids reduced a* and TSS, whereas promoted TA. L-ascorbic acid was reduced by grafting (from -23 to -45%), in the S. pimpinellifolium group too, indicating, even in low vigor rootstocks, a dilution effect worsening this nutraceutical trait of tomatoes.

Preliminar histological study of the thymus in regularly slaughtered Chianina beef cattle to improve methods for the detection of illicit treatments.

Chianina is an Italian cattle breed appreciated for its meat and resilience skills. No standard values are present in literature regarding Chianina thymic involution. A possible early physiological involution has been reported during the Italian National Residue Plan screening tests. The aim of this work was to perform an anatomo­histopathological study of the thymus in Chianina cattle to improve knowledge about thymic involution in this breed. Forty Chianina bulls (16­24 months old), never treated with corticosteroids and regularly slaughtered in the Umbria region (Italy), were enrolled. Animals aged 19­21 months which received score 3 thymic atrophy had a prevalence of 0.15 (CI 95%: 0.02­0.45%), while the prevalence was 0.29 (CI 95%: 0.10­0.56%) among animals aged 22­24 months. The thymus/carcass weight and thymic cortex/medulla ratio resulted close to those reported in cattle experimentally challenged with corticosteroids. Results suggest that the Chianina breed could be characterized by a physiological premature involution of the thymus gland in comparison to other breeds. These results represent a starting point to increase the reliability of the National Residue Plan histological screening test.

Seed Dormancy Breaking and Germination in Bituminaria basaltica and B. bituminosa (Fabaceae).

Most legumes are well-known for the physical dormancy of their seeds; hence, the implementation of appropriate scarification techniques is essential for introducing new legume crops within agricultural systems. This study investigated morpho-anatomical traits and dormancy-breaking requirements in two taxa of the genus Bituminaria: the widespread B. bituminosa and the point endemic B. basaltica. As the species under investigation show monospermic indehiscent legumes, pods were used in this research. We performed pod trait measurements, light microscopy observations on the seed coat anatomical structure, and germination tests after mechanical, thermal, and chemical scarification treatments for seed dormancy breaking. Moreover, germination performance at different pod maturity stages and storage times was tested. Differences in morpho-anatomical traits were found, with B. basaltica having a thicker palisade cell layer and B. bituminosa showing larger pods. All of the scarification treatments proved to be able to break physical dormancy, with mechanical and chemical scarification being the most effective methods in both species. Nevertheless, dormancy-breaking treatments performed better in B. bituminosa. Seeds at early pod maturity stages showed higher germination capacity in both species. Overall, this research provided background knowledge on seed collection time, storage strategy, and effective pre-sowing treatment, which might contribute to enhance propagation and use of Bituminaria species for multiple purposes. Under this perspective, the future characterization of additional Bituminaria genetic resources from other Mediterranean populations will have remarkable importance.

Effects of Animal, Climatic, Hunting and Handling Conditions on the Hygienic Characteristics of Hunted Roe Doer (Caprelous capreolus L.).

The population of wild animals is increasing, and control strategies based on selective hunting are among the major options adopted. The game meat obtained is therefore available for controlled and certified valuable chains. The understanding of carcass contamination and the factors affecting it is therefore crucial to ensure meat safety and prolonged shelf-life. The carcass hygiene of 64 hunted wild male roe deer (Capreolus capreolus L.) was evaluated in relation to factors potentially affecting it. Aerobic colony and Enterobacteriaceae counts, as well as Salmonella spp. and Listeria monocytogenes detection, were performed. The interaction of the microbial determination with age and weight of the animals, the climate conditions, the shooting procedure, the time between the killing and the evisceration as well as the time of storage of the carcasses in refrigerated conditions before skinning, were evaluated. Neither Salmonella spp. nor Listeria monocytogenes were detected on the carcasses and the average loads detected were 3.39 ± 1.06 UFC/cm2 and 2.27± 1.11 UFC/cm2 for the aerobic colony count and Enterobacteriaceae count, respectively. The loads detected are similar to those reported by UE legislation for slaughtered species. The time of storage before skinning, the environmental temperature during hunting and the time between shooting and evisceration, associated with animal weight, affect the carcass hygiene and must be taken into careful consideration by hunters as food business operators.

Loss of trifluralin metabolic resistance in Lolium rigidum plants exposed to prosulfocarb recurrent selection.

BACKGROUND: Resistance to the dinitroaniline herbicide trifluralin in Lolium rigidum (annual ryegrass) often is mediated by the enhanced capacity to metabolize the herbicide to less toxic polar conjugates and/or by functionally recessive target-site mutations in α-tubulin. RESULTS: In two L. rigidum populations possessing enhanced trifluralin metabolism, resistance was largely reversed by recurrent selection with the thiocarbamate herbicide prosulfocarb (i.e. plant survival was two- to >20-fold lower). Their ability to metabolize trifluralin was significantly decreased (by ≈2.3-fold) following recurrent prosulfocarb selection, to levels comparable to those observed in susceptible plants or when trifluralin metabolism was inhibited by treatment with the insecticide phorate. CONCLUSIONS: This study provides evidence that trait(s) enabling efficient trifluralin metabolism in L. rigidum are purged from the population under prosulfocarb recurrent selection. The level of trifluralin metabolism in vitro and its inhibition caused by phorate action on trifluralin-metabolizing enzyme(s) is equivalent to the effect produced by prosulfocarb selection. The hypothetical link between the two phenomena is that the putative monooxygenase(s) conferring trifluralin metabolic resistance also mediate the activation of prosulfocarb to its toxic sulfoxide. Thus, we speculate that survival to prosulfocarb via a lack of metabolic herbicide activation, and survival to trifluralin conferred by enhanced herbicide metabolism, are mutually exclusive. These findings not only open up a new research direction in terms of the interaction between different herbicide resistance mechanisms in L. rigidum, but also offer strategies for immediate management of the population dynamics of metabolism-based resistance in the field. © 2020 Society of Chemical Industry.

Fungicides may have differential efficacies towards the main causal agents of Fusarium head blight of wheat.

BACKGROUND: Fusarium head blight (FHB) is a complex disease of wheat and barley caused by several Fusarium species. In recent years, a variation in the composition of the FHB community has been observed in several wheat cultivation areas across the world. In detail, F. avenaceum and F. poae increased their frequencies, while, a lower F. graminearum and F. culmorum incidence was simultaneously observed. These shifts within the FHB complex might have been caused by different factors, including the selective pressure caused by fungicides used to control the disease in the field. Therefore, the present study was carried out to evaluate, both in in vitro experiments and in field trials, the activity of commonly used fungicides of wheat (tebuconazole, metconazole, prothioconazole and prochloraz) towards the above mentioned four Fusarium species. RESULTS: A preliminary in vitro assay revealed that low concentrations of all tested fungicides caused the incomplete reduction of fungal development. Furthermore, F. poae and F. avenaceum showed, at the same time, a lower sensitivity to all tested fungicides. In field trials, all fungicides showed an activity against the four Fusarium species. However, F. avenaceum exhibited a reduced sensitivity to metconazole. The lower efficacy of metconazole towards F. avenaceum was also confirmed by an additional in vitro experiment on several F. avenaceum and F. graminearum different strains. CONCLUSION: The selective pressure exerted by the extensive use of certain fungicides may influence population dynamics of Fusarium species due to their different sensitivity. © 2020 Society of Chemical Industry.

Aspergillus, Penicillium and Cladosporium species associated with dried date fruits collected in the Perugia (Umbria, Central Italy) market.

A total of 20 dried date samples, chosen as representative among those available on the Perugia (Umbria, Central Italy) market, were analyzed for the possible occurrence of fungal species and related contamination by fungal secondary metabolites. Twenty-six isolates, representative of the total mycobiota, were obtained and morphologically identified as belonging to the genera Aspergillus, Penicillium and Cladosporium. Inside each genus, molecular characterization (by partial sequencing of ITS region and/or ß-tubulin and calmodulin regions for Aspergillus and Penicillium isolates or actin region for Cladosporium isolates) and in vitro mycotoxigenic profile characterization (by LC-MS/MS analysis) showed the presence of the following species: A. flavus, A. tubingensis, P. brevicompactum, P. chrysogenum, P. crustosum, P. glabrum, P. solitum, P. venetum, C. cladosporioides, C. limoniforme and C. halotolerans, with A. tubingensis as the prevalent species and P. crustosum, P. solitum, P. venetum and C. limoniforme first reported here on dates. Date packaging and format showed an effect on the incidence of isolated fungi, with the lowest incidence recovered from whole dates and in hermetic bag packaging. These findings can be useful both for dried dates producers and consumers, guiding them towards choices of packaging and format with a lower risk of mycotoxigenic species presence. However, no fungal metabolites were detected in the dried date samples analyzed, which were therefore regarded as safe for human consumption, underlining the absence of correspondence between fungal isolation and mycotoxin contaminations.

Cultivation Area Affects the Presence of Fungal Communities and Secondary Metabolites in Italian Durum Wheat Grains.

In this study, durum wheat kernels harvested in three climatically different Italian cultivation areas (Emilia Romagna, Umbria and Sardinia) in 2015, were analyzed with a combination of different isolation methods to determine their fungal communities, with a focus on Fusarium head blight (FHB) complex composition, and to detect fungal secondary metabolites in the grains. The genus Alternaria was the main component of durum wheat mycobiota in all investigated regions, with the Central Italian cultivation area showing the highest incidence of this fungal genus and of its secondary metabolites. Fusarium was the second most prevalent genus of the fungal community in all cultivation environments, even if regional differences in species composition were detected. In particular, Northern areas showed the highest Fusarium incidence, followed by Central and then Southern cultivation areas. Focusing on the FHB complex, a predominance of Fusariumpoae, in particular in Northern and Central cultivation areas, was found. Fusariumgraminearum, in the analyzed year, was mainly detected in Emilia Romagna. Because of the highest Fusarium incidence, durum wheat harvested in the Northern cultivation area showed the highest presence of Fusarium secondary metabolites. These results show that durum wheat cultivated in Northern Italy may be subject to a higher FHB infection risk and to Fusarium mycotoxins accumulation.

In Vitro Fumonisin Biosynthesis and Genetic Structure of Fusarium verticillioides Strains from Five Mediterranean Countries.

Investigating the in vitro fumonisin biosynthesis and the genetic structure of Fusarium verticillioides populations can provide important insights into the relationships between strains originating from various world regions. In this study, 90 F. verticillioides strains isolated from maize in five Mediterranean countries (Italy, Spain, Tunisia, Egypt and Iran) were analyzed to investigate their ability to in vitro biosynthesize fumonisin B1, fumonisin B2 and fumonisin B3 and to characterize their genetic profile. In general, 80% of the analyzed strains were able to biosynthesize fumonisins (range 0.03-69.84 µg/g). Populations from Italy, Spain, Tunisia and Iran showed a similar percentage of fumonisin producing strains (>90%); conversely, the Egyptian population showed a lower level of producing strains (46%). Significant differences in fumonisin biosynthesis were detected among strains isolated in the same country and among strains isolated from different countries. A portion of the divergent FUM1 gene and of intergenic regions FUM6-FUM7 and FUM7-FUM8 were sequenced to evaluate strain diversity among populations. A high level of genetic uniformity inside the populations analyzed was detected. Apparently, neither geographical origin nor fumonisin production ability were correlated to the genetic diversity of the strain set. However, four strains from Egypt differed from the remaining strains.