Investigating the effect of acoustic waves on spoilage fungal growth and shelf life of strawberry fruit.

The effects of acoustic waves on growth inhibition of food spoilage fungi (Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus and Botrytis cinerea) on the medium and strawberry surfaces were investigated. Firstly, single-frequency sound waves (250, 500, 1000, 2000, 4000, 8000, 12,000 and 16,000 Hz) were induced on inoculated medium with fungi spores for 24 h and growth diameter of each mold was evaluated during the incubation period. In the second stage, the sound waves with two frequencies of 250 Hz and 16,000 Hz were induced on inoculated strawberries with fungi spores at 5 °C for different times (2, 4, 6, 8 and 10 days). The results from the first stage indicated that the sound waves inhibited the growth of A. niger (20.02%) at 250 Hz and B. cinerea (4/64%) at 4000 Hz on potato dextrose agar (PDA) surface. Also, comparison of the growth diameter of some species of Aspergillus revealed various responses in presence of 250 Hz frequency. In the second stage, applying a frequency of 250 Hz over a period of 10 days proved to be more effective in inhibiting the growth of A. niger and B. cinerea on strawberries inoculated with fungal spores. Consequently, the shelf lives of the strawberries significantly increased to 26 days and 18 days, respectively, under this treatment. Based on the findings, it is concluded that sounding with acoustic waves can be used as a green and cheap technology along with other technologies to improve food safety.

Use of encapsulated pomegranate seed oil in novel coarse and nanosized materials for improving the storage life of strawberry.

Different-sized pomegranate seed oil-based emulsions (coarse (CsP) and nanoemulsions (NsP): 1246 and 325 nm) were successfully prepared. Strawberries treated with NsP and CsP showed a significant decrease (p < 0.05) in yeast-mold counts (TMY) by 1.80 log CFU g-1, and mesophilic aerobic bacteria counts (TMAB) decreased (p < 0.05) by 0.91 log CFU g-1, respectively. CsP- and NsP-treated strawberries had a TPC of 74.45 and 82.35 mg GAE kg-1, respectively, while control samples had a TPC of 44.24 mg GAE kg-1. The strawberries treated with NsP exhibited the highest antioxidant capacity with 179.44 mol TEAC g-1. After treatment with a coarse emulsion, severity levels of A. niger and B. cinerea were 60 and 73 % while the nanoemulsion treatment significantly reduced severity levels to 55.3 and 56 %. The coarse and nanoemulsions may have potential use within the food industry owing to their antioxidant and antifungal properties as well as their ability to enhance strawberry quality and function.

Resistance to Seven Site-Specific Fungicides in Botrytis cinerea from Greenhouse-Grown Ornamentals.

The fungal pathogen Botrytis cinerea is a notorious problem on many floriculture greenhouse hosts including petunia, geranium, and poinsettia; these key crops contribute to the $6.43 billion U.S. ornamental industry. While growers use cultural strategies to reduce relative humidity and free moisture to limit Botrytis blight, fungicides remain a primary component of control programs. Isolates (n = 386) of B. cinerea sampled from symptomatic petunia, geranium, and poinsettia in Michigan greenhouses from 2018 to 2021 were screened for resistance to eight fungicides belonging to seven Fungicide Resistance Action Committee (FRAC) groups. Single-spored isolates were subjected to a germination-based assay using previously defined discriminatory doses of each fungicide. Resistance was detected to thiophanate-methyl (FRAC 1; 94%), pyraclostrobin (FRAC 11; 80%), boscalid (FRAC 7; 67%), iprodione (FRAC 2; 65%), fenhexamid (FRAC 17; 38%), cyprodinil (FRAC 9; 38%), fludioxonil (FRAC 12; 21%), and fluopyram (FRAC 7; 13%). Most isolates (63.5%) were resistant to at least four FRAC groups, with 8.7% of all isolates demonstrating resistance to all seven FRAC groups tested. Resistance frequencies for each fungicide were similar among crops, production regions, and growing cycles but varied significantly for each greenhouse. Phenotypic diversity was high, as indicated by the 48 different fungicide resistance profiles observed. High frequencies of resistance to multiple fungicides in B. cinerea populations from floriculture hosts highlight the importance of sustainable and alternative disease management practices for greenhouse growers.

The biocontrol agent Lactiplantibacillus plantarum AMBP214 is dispersible to plants via bumblebees.

IMPORTANCE: Plant protection products are essential for ensuring food production, but their use poses a threat to human and environmental health, and their efficacy is decreasing due to the acquisition of resistance by pathogens. Stricter regulations and consumer demand for cleaner produce are driving the search for safer and more sustainable alternatives. Microbial biocontrol agents, such as microorganisms with antifungal activity, have emerged as a promising alternative management strategy, but their commercial use has been limited by poor establishment and spread on crops. This study presents a novel system to overcome these challenges. The biocontrol agent Lactiplantibacillus plantarum AMBP214 was spray-dried and successfully dispersed to strawberry flowers via bumblebees. This is the first report of combining spray-dried, non-spore-forming bacteria with pollinator-dispersal, which scored better than the state-of-the-art in terms of dispersal to the plant (CFU/flower), and resuscitation of the biocontrol agent. Therefore, this new entomovectoring system holds great promise for the use of biocontrol agents for disease management in agriculture.

Photoantimicrobial chitosan-gelatin-pomegranate peel extract films for strawberries preservation: From microbiological analysis to in vivo safety assessment.

This study aimed to investigate the application of biopolymeric materials (chitosan, gelatin, and pomegranate peel extract as photosensitizer) and antimicrobial photodynamic therapy (aPDT) on the physicochemical and microbial safety of strawberries. The photosensitizer potential of the materials was confirmed by a light-dose-dependent photobleaching profile. The application of light (525 nm; 50 J cm-2) decreased by >2 log CFU mL-1 the survival of Staphylococcus aureus on the surface of the photoactive-biopolymeric films. Moreover, the materials did not present in vivo cytotoxicity using Danio rerio (Zebrafish) as well as cytophytotoxic, genotoxic, or mutagenic potentials against Allium cepa plant model, which points out their safety to be used as films without posing a risk to the humans and the environment. The photoactive-polymeric coatings were able to maintain the strawberries weight, and the association with green light was 100 % effective in delaying fungal contamination. These coated-strawberries presented a significant reduction in S. aureus survival after light application (5.47-4.34 log CFU mL-1). The molecular level analysis of the photoactive compound cyanidin-3-glucoside indicates absorption on UV-Vis consistent with aPDT action. Therefore, this study showed that the antimicrobial effects of aPDT combined with photoactive-biopolymeric coatings were enhanced, while the quality of the strawberries was maintained.

Eco-sustainable coatings based on chitosan, pectin, and lemon essential oil nanoemulsion and their effect on strawberry preservation.

Films and coatings manufactured with bio-based renewable materials, such as biopolymers and essential oils, could be a sustainable and eco-friendly alternative for protecting and preserving agricultural products. In this work, we developed films and coatings from pectin and chitosan to protect strawberries (Fragaria x ananassa Duch.) from spoilage and microbial contamination. We developed three coatings containing equal amounts of glycerol and Sicilian lemon essential oil (LEO) nanoemulsion. We identified seventeen chemicals from LEO by GC-MS chromatogram, including d-limonene, α-Pinene, ß-Pinene, and γ-Terpinene. The pectin and chitosan coatings were further characterized using different physicochemical, mechanical, and biological methods. The films demonstrated satisfactory results in strength and elongation at the perforation as fruit packaging. In addition, the coatings did not influence the weight and firmness of the strawberry pulps. We observed that 100 % essential oil was released in 1440 min resulting from the erosion process. Also, the oil preserved the chemical stability of the films. Antioxidant activity (AA), measured by Electron Paramagnetic Resonance (EPR), showed that the coatings loaded with 2 % LEO nanoemulsion (PC + oil) showed that almost 50 % of AA from LEO nanoemulsion was preserved. The chitosan and the pectin-chitosan coatings (PC + oil) inhibited filamentous fungi and yeast contaminations in strawberries for at least 14 days, showing a relationship between the AA and antimicrobial results.

Early detection of Botrytis cinerea in strawberry fruit during quiescent infection using selected ion flow tube mass spectrometry (SIFT-MS).

Botrytis cinerea is a devastating pathogen that can cause huge postharvest losses of strawberry. Although this fungus usually infects strawberries through their flowers, symptoms mainly appear when fruit are fully mature. A fast and sensitive method to detect and quantify the fungal infection, prior to symptom development, is, therefore, needed. In this study, we explore the possibility of using the strawberry volatilome to identify biomarkers for B. cinerea infection. Strawberry flowers were inoculated with B. cinerea to mimic the natural infection. First, quantitative polymerase chain reaction (qPCR) was used to quantify B. cinerea in the strawberry fruit. The detection limit of qPCR for B. cinerea DNA extracted from strawberries was 0.01 ng. Subsequently, changes in the fruit volatilome at different fruit developmental stages were characterized using gas chromatography - mass spectrometry (GC-MS) and selected ion flow tube mass spectrometry (SIFT-MS). Based on GC-MS data, 1-octen-3-ol produced by B. cinerea was confirmed as a potential biomarker of B. cinerea infection. Moreover, the product ion NO+ 127, obtained by SIFT-MS measurements, was proposed as a potential biomarker for B. cinerea infection by comparing its relative level with that of 1-octen-3-ol (obtained by GC-MS) and B. cinerea (obtained by qPCR). Separate PLS regressions were carried out for each developmental stages, and 11 product ions were significantly altered at all developmental stages. Finally, PLS regressions using these 11 ions as variables allowed the discrimination between samples containing different amount of B. cinerea. This work showed that profiling the fruit's volatilome using SIFT-MS can be used as a potential alternative to detect B. cinerea during the quiescent stage of B. cinerea infection prior to symptom development. Moreover, the corresponding compounds of potential biomarkers suggest that the volatile changes caused by B. cinerea infection may contribute to strawberry defense.

Early on-site detection of strawberry anthracnose using portable Raman spectroscopy.

We developed a method for the early on-site detection of strawberry anthracnose using a portable Raman system with multivariate statistical analysis algorithms. By using molecular markers based on Raman spectra, the proposed method can detect anthracnose in strawberry stems 3 days after exposure to Colletotrichum gloeosporioides. A fiber-optic probe was applied for the portable Raman system, and the acquisition time was 10 s. We found that the molecular markers were closely related to the following subjects: i) an increase in amide III and fatty acids of C. gloeosporioides invading strawberry stems (Raman bands at 1180-1310 cm-1) and ii) a decrease in metabolites in strawberry plants, such as phenolic compounds and terpenoids (Raman bands at 760, 800, and 1523 cm-1). We also found that the increased fluorescence background caused by various chromophores within the invading C. gloeosporioides could serve as a marker. A two-dimensional cluster plot obtained by principal component analysis (PCA) showed that the three groups (control, fungal infection, and pathogen) were distinguishable. The linear discriminant analysis (LDA)-based prediction algorithm could identify C. gloeosporioides infection with a posterior probability of over 40%, even when no symptoms were visible on the inoculated strawberry plants.

Systemic Colonization of Xanthomonas fragariae Strain YL19 Causing Dry Cavity Rot of Strawberry Crown Tissue in China.

Xanthomonas fragariae usually causes angular leaf spot (ALS) of strawberry, a serious bacterial disease in many strawberry-producing regions worldwide. Recently, a new strain of X. fragariae (YL19) was isolated from strawberry in China and has been shown to cause dry cavity rot in strawberry crown. In this study, we constructed a green fluorescent protein (GFP)-labeled Xf YL19 (YL19-GFP) to visualize the infection process and pathogen colonization in strawberries. Foliar inoculation of YL19-GFP resulted in the pathogen migrating from the leaves to the crown, whereas dip inoculation of wounded crowns or roots resulted in the migration of bacteria from the crowns or roots to the leaves. These two invasion types both resulted in the systematic spread of YL19-GFP, but inoculation of a wounded crown was more harmful to the strawberry plant than foliar inoculation. Results increased our understanding of the systemic invasion of X. fragariae, and the resultant crown cavity caused by Xf YL19.

Probiotic Bacteria, Anaerobic Soil Disinfestation, and Mustard Cover Crop Biofumigation Suppress Soilborne Disease and Increase Yield of Strawberry in a Perennial Organic Production System.

Black root rot complex and crown rot of strawberry caused by soilborne fungi limit sustainable strawberry production in the northeastern United States, especially in perennial systems, including matted row and plasticulture. As pathogen populations build up over time in the rhizosphere and infect the root system, feeder roots are pruned, which diminishes nutrient and water uptake and causes stunted plant growth or death. Alternative management options are needed for many organic and small growers who can't use chemical fumigants due to new regulations and potential health hazards. Strawberry plug plants were grown on beneficial microbe-inoculated or uninoculated planting mix followed by transplanting in fruiting field plots that either was biofumigated with mustard cover crop (MCC), anaerobically disinfested (ASD), or left untreated. Different combinations of plug plants and field plot treatments were used to determine the efficacy of individual treatments or synergistic effects from combination treatment. Plug plants were transplanted in pretreated plastic mulched raised beds and grown following a typical organically recommended production system. Plants grown on TerraGrow (TG)-inoculated planting mix showed enhanced plant vigor in the fruiting field compared with untreated plants. Weeds that grew through planting holes were significantly (P ≤ 0.045) suppressed in ASD plots compared with untreated plots in the first year. Plants treated with a combination treatment of TG and ASD had significantly higher fruit yield in both years (2019 and 2020), although the difference was greater in the second year. Plant vigor and survival in treated plots except MCC were also significantly higher in the second year compared with the untreated control. Suppression of pathogenic microbes and plant vigor improvement in treated plots appear to be the factors providing beneficial effects and higher net economic return. Taken together, our results suggest that a combination of beneficial microbes and ASD could be an alternative to synthetic fumigation in a perennial strawberry production system.

A Genomic Resource for the Strawberry Powdery Mildew Pathogen Podosphaera aphanis.

Powdery mildew is one of the most economically destructive diseases in protected strawberry production. Here we present the first genome assembly for Podosphaera aphanis, the causal agent of powdery mildew on strawberry. This obligate-biotrophic fungal pathogen was sampled from a naturally occurring outbreak on Fragaria × ananassa 'Malling Centenary' plants grown under cover in the United Kingdom. Assembled reads resolved a 55.6 Mb genome, composed of 12,357 contigs whose annotation led to prediction of 17,239 genes encoding 17,328 proteins. The genome is highly-complete, with 97.5% of conserved single-copy Ascomycete genes shown to be present. This annotated P. aphanis genome provides a molecular resource for further investigation into host-pathogen interactions in the strawberry powdery mildew pathosystem.

Establishment of the Recombinase Polymerase Amplification-Lateral Flow Dipstick Detection Technique for Fusarium oxysporum.

Fusarium oxysporum causes crown rot, wilt, root rot, and many other major plant diseases worldwide. During the progression of strawberry crown rot disease, the pathogen is transmitted from the mother plant to the seedling through the stolon, with obvious characteristics of latent infection. Therefore, rapid and timely detection of F. oxysporum is important for efficient disease management. In this study, a recombinase polymerase amplification-lateral flow dipstick (RPA-LFD) detection technique was developed for the rapid detection of F. oxysporum on strawberry plants by targeting the CYP51C gene, which is unique to Fusarium spp. Because this RPA-LFD detection technique was highly specific to F. oxysporum, other Fusarium and non-Fusarium fungi were not detected. The optimal reaction temperature and time for this technique were 39°C and 8 min, respectively. The detection limit was 1 pg of F. oxysporum genomic DNA in a 50-µl reaction system. A total of 46 strawberry plants with or without crown rot symptoms collected from Jiande, Changxing, and Haining in Zhejiang Province were further assessed for F. oxysporum infection using both RPA-LFD and traditional tissue isolation techniques. The RPA-LFD test showed that 32 of the 46 strawberry plants tested were positive for F. oxysporum, while in the traditional isolation technique, F. oxysporum was isolated from 30 of the 46 strawberry plants. These results suggest that our established RPA-LFD method is rapid, sensitive, and highly specific in detecting F. oxysporum infection in strawberry plants.

Survival of Xanthomonas fragariae on Common Materials.

Xanthomonas fragariae causes strawberry angular leaf spot (ALS), an important disease for the strawberry nursery industry in North America. To identify potential inoculum sources, the survival of X. fragariae was examined on the surfaces of 11 common materials found in nurseries: corrugated cardboard, cotton balls, cotton cloth (t-shirt), strawberry leaf, sheet metal, plastic, rubber, Tyvek, wood (balsa), glass (microscope slide), and latex (latex glove). Prefabricated rectangular samples (7.62 by 2.54 cm) of each material were immersed in a bacterial suspension for 15 min, after which the samples were stored at approximately 20°C (room temperature) or -4°C (the cold storage temperature for dormant plants in strawberry nurseries) for 1, 3, 7, 14, 30, 60, 90, 180, 270, and 365 days after inoculation (DAI). After the storage period elapsed, bacteria were recovered from the surfaces of each of the samples with phosphate-buffered saline (PBS)-soaked cotton balls. Survival rate was determined with a viability real-time quantitative PCR procedure and in a plant bioassay that involved rub inoculation of strawberry leaflets with the PBS-soaked cotton balls used to recover bacteria from the samples. Results showed that X. fragariae could survive on all surfaces but that survival rate differed among materials and storage temperature. All materials were capable of harboring viable bacteria up to 7 DAI when stored at -4°C based on the formation of lesions on inoculated leaves in the plant bioassay. The longest survival observed was 270 DAI on cardboard stored at -4°C. At room temperature, cardboard, cotton balls, cotton t-shirt, and strawberry leaf tissue supported small bacterial populations up to 14 DAI. The information from this study can be used to improve sanitation practices for ALS management in strawberry nurseries.

Efficiency of nanoemulsion of essential oils to control Botrytis cinerea on strawberry surface and prolong fruit shelf life.

Strawberry fruit is highly susceptible to decay by fungi. The objective of this study was to determine if essential oils (EOs) or nano-emulsions (Nano-EM) of EOs from Thymus vulgaris (Th), Matricaria chamomilla (Mc), Pistacia atlantica (Pa), or Mentha longifolia (Me) could inhibit growth of strawberry spoilage fungi Botrytis cinerea and their effect, if any, on strawberry quality parameters. An In vitro study showed that Th and Me EOs had the same minimal inhibitory concentrations (MIC) of 0.021 % while the MICs for Mc and Pa EOs were 0.9 % and 1.5 %, respectively. Th and Me EOs were used for subsequent experiments. In the second experiment, the application of Th and Me EOs and their nano-EM at 0.021, 0.1, 0.5 and 1 % were studied to control B. cinerea growth on the fruit surface. Nano-EM of EOs had higher antifungal activity in the control of B. cinerea than EOs on fruit surface. Generally, antifungal activity was increased at higher concentrations of Nano-EM, but in the case of EOs, their antifungal activity was not increased by increasing concentration. Nano-EM of EOs with 0.5 % was selected for further study. Finally, the quality changes and postharvest losses of fruit treated with Nano-EM of EOs of Th and Me at 4 °C were studied. The results of third experiment showed that Nano-EM of both EOs reduced microbial load, decay index, weight loss and induced greater firmness, vitamin C, total flavonoid and antioxidant activity in strawberry during storage. NanoEM-ThEO 0.5 % was more effective than NanoEM-MeEO 0.5 % to retain strawberry firmness, vitamin C and total flavonoid.

Efficacy of Single- and Multi-Site Fungicides Against Neopestalotiopsis spp. of Strawberry.

Recently, the Florida strawberry industry faced unprecedented outbreaks of an emerging disease caused by the fungus Neopestalotipsis spp. Currently, there are no fungicides labeled to control this disease in the United States and the efficacy of single- and multisite fungicides is unknown. Therefore, this study aimed to determine the in vitro sensitivity of Neopestalotiopsis spp. isolates to fungicides with different modes of action and to evaluate the efficacy of these products on detached fruit and in the field. In preliminary in vitro tests, 30 commercially available fungicides were screened using discriminatory doses. The effective concentration that inhibited mycelial growth by 50% was determined for the most effective single-site fungicides. Four field experiments were conducted during the 2019-20, 2020-21, and 2021-22 seasons to determine product efficacy in managing the disease. The single-site fungicides fludioxonil, fluazinam, and sterol demethylation inhibitors, and the multisite fungicides captan, thiram, and chlorothalonil were the most effective in inhibiting pathogen growth and suppressing disease development. Conversely, products in Fungicide Resistance Action Committee (FRAC) groups 1 (methyl benzimidazole carbamate) and 7 (succinate-dehydrogenase inhibitors), except for benzovindiflupyr, were not effective against Neopestalotiopsis spp. Resistance to fungicides from FRAC group 11 (e.g., azoxystrobin) was confirmed by the presence of the G143A mutation in the cytochrome b gene together with inoculation tests and field trials. Our results provide information to support or discourage the registration of fungicides to manage Neopestalotiopsis fruit rot and leaf spot in strawberry production.

Soilborne pathogens affect strawberry fruit flavor and quality.

Fusarium oxysporum f. sp. fragariae and Macrophomina phaseolina are soilborne fungi leading impactful economical losses to strawberry growers worldwide. Symptoms caused by both pathogens are very similar and include vascular discoloration, wilting, stunting, and dieback of plants, but no fruit damage. An extraction of phenolic and volatile compounds was performed on strawberry fruits from three different cultivars while being grown in a plant growth medium infested by each pathogen. Inoculated plants showed higher content of certain phenolic compounds which have antifungal and antioxidant activity and may have a positive impact on strawberry shelf life. On the other hand, root and vascular infections caused by F. oxysporum and M. phaseolina were able to significantly alter strawberry aroma by reducing or increasing the content of specific volatile compounds which also have an important impact on fruit quality. The changes induced in the aroma profiles of the three strawberry cultivars do not only have organoleptic and economic implications for strawberry growers but play an important role in the plant defense system against pathogens. The results indicate a potential of this line of research to develop new tools for the detection and control of soil pathogens.

Taxonomical and functional composition of strawberry microbiome is genotype-dependent.

INTRODUCTION: Specific microbial communities are associated to host plants, influencing their phenotype and fitness.Despite the rising interest in plant microbiome, the role of microbial communities associated with perennial fruit plants remains overlooked. OBJECTIVES: This work provides the first comprehensive descriptionof the taxonomical and functional bacterial and fungal microbiota of below- and above-ground organsof three commercially important strawberry genotypes under cultural conditions. METHODS: Strawberry-associatedfungal and bacterial microbiomes were characterised by Next-Generation Sequencing and the potential functions expressed by the bacterial microbiome were analysed by both in silico and in vitro characterisation of plant growth-promoting abilities of native bacteria. Additionally, the association between the strawberry microbiome, plant disease tolerance, plant mineral nutrient content, and fruit quality was investigated. RESULTS: Results showed that thestrawberry core microbiome included 24 bacteria and 15 fungal operational taxonomicunits (OTUs).However, plant organ and genotype had a significant role in determining the taxonomical and functional composition of microbial communities. Interestingly, the cultivar with the highesttolerance against powdery mildew and leaf spot and the highest fruit productivity was the only one able to ubiquitously recruit the beneficial bacterium, Pseudomonasfluorescens, and to establish a mutualistic symbiosis with the arbuscular mycorrhizaRhizophagus irregularis. CONCLUSION: This work sheds light on the interaction of cultivated strawberry genotypes with a variety of microbes and highlights the importance of their applications to increase the sustainability of fruit crop production.

Bio-nanocomposite edible coatings based on arrowroot starch/cellulose nanocrystals/carnauba wax nanoemulsion containing essential oils to preserve quality and improve shelf life of strawberry.

This study investigated the effects of bio-nanocomposite coatings developed using arrowroot starch (AA), cellulose nanocrystals (CNC), carnauba wax nanoemulsion (CWN), and Cymbopogon martinii and Mentha spicata essential oils (CEO and MEO, respectively) on the physicochemical, microbiological, bioactive, antioxidant, and aromatic characteristics of strawberries cv. 'Oso Grande' in refrigerated storage for 12 days. The coatings improved the shelf life and stability of strawberries, minimizing their weight loss (2.6-3.9 %), as well as changes in color and texture (except for those coated with CEO), titratable acidity, pH, soluble solids, anthocyanins, phenolic compounds, ascorbic acid content, and antioxidant activity compared with uncoated control strawberries. The bio-nanocomposite coatings containing MEO and CEO also exhibited antimicrobial activity, reduced visible fungal deterioration (40-60 %), and reduced microbial load (3.59-4.03 log CFU g-1 for mesophilic aerobic bacteria and 4.45-5.22 log CFU g-1 for fungi and yeast) during storage. They also significantly reduced the severity of decay caused by inoculation with Botrytis cinerea or Rhizopus stolonifer. The coatings altered the volatile profile of the fruits during storage, decreasing aldehyde and alcohol concentrations and increasing ester concentrations. Thus, these bio-nanocomposite coatings, especially those containing MEO, can be used as antimicrobial coating materials to preserve the post-harvest quality of fresh strawberries.

Antifungal effects of volatile compounds produced by Tetrapisispora sp. strain 111A-NL1 as a new biocontrol agent on the strawberry grey mold disease.

An antagonistic yeast strain was isolated from the strawberry fruit cv. Paros, and its antifungal properties against Botrytis cinerea causal agent of strawberry grey mold disease were evaluated under in vitro and in vivo experiments. The isolate was tentatively identified as Tetrapisispora sp. strain 111A-NL1 based on phenotypic characteristics and sequence analysis of D1/D2 domains of the 26S rRNA gene. Volatile organic compounds (VOCs) produced by the 111A-NL1 strain inhibited the mycelial growth of fungal pathogen (75.19%) and conidial germination (63.34%); however, inhibition percentage of mycelial growth of pathogen by dual culture test was less (19.49%). Also, the strain produced pectinase, siderophore, chitinase, IAA, as well as gibberellin, and could solubilize phosphate. Additionally, the disease severity of strawberry grey mold was decreased by employing living cells and volatile metabolites methods by 47.61% and 74.05%, respectively, in comparison with untreated control seven days after inoculation. Therefore, its mode of action might consist of antibiosis and VOCs production by yeast strain 111A-NL1 against B. cinerea. The VOCs released by strain 111A-NL1 were analyzed, and thirty-three chemical compounds were determined by gas chromatography-mass spectroscopy (GC-MS). Out of them, Decane (12.79%), Squalene (9.60%), Undecane (7.98%), Benzene, 1,2,3-trimethyl- (7.67%), Nonane, 2,6-dimethyl- (5.69%), Benzene, 1-ethyl-3-methyl- (5.55%), Mesitylene (4.17%), and Phenylethyl Alcohol (3.33%) were the major components. In addition, the selected strain reduced natural decay incidence and weight loss of fruit, and preserved quality parameters of strawberry fruit including firmness, soluble solids content, and titratable acidity. This research averred, for the first time, that the creation of VOCs by Tetrapisispora sp. strain 111A-NL1 could play an essential role as a biofumigant in the antifungal activity against strawberry grey mold.

Endophytic Trichoderma spp. can protect strawberry and privet plants from infection by the fungus Armillaria mellea.

Armillaria mellea is an important fungal pathogen worldwide, affecting a large number of hosts in the horticulture and forestry industries. Controlling A. mellea infection is expensive, labour intensive and time-consuming, so a new, environmentally friendly management solution is required. To this effect, endophytic Trichoderma species were studied as a potential protective agent for Armillaria root rot (ARR) in strawberry and privet plants. A collection of forty endophytic Trichoderma isolates were inoculated into strawberry (Fragaria × ananassa) plants and plant growth was monitored for two months, during which time Trichoderma treatment had no apparent effect. Trichoderma-colonised strawberry plants were then inoculated with A. mellea and after three months plants were assessed for A. mellea infection. There was considerable variation in ARR disease levels between plants inoculated with different Trichoderma spp. isolates, but seven isolates reduced ARR below the level of positive controls. These isolates were further tested for protective potential in Trichoderma-colonized privet (Ligustrum vulgare) plants where five Trichoderma spp. isolates, including two highly effective Trichoderma atrobrunneum isolates, were able to significantly reduce levels of disease. This study highlights the potential of plants pre-colonised with T. atrobrunneum for effective protection against A. mellea in two hosts from different plant families.