Growth and Physiological Characteristics of Strawberry Plants Cultivated under Greenhouse-Integrated Semi-Transparent Photovoltaics.

The integration of semi-transparent photovoltaics into the roof of greenhouses is an emerging technique used in recent years, due to the simultaneous energy and food production from the same piece of land. Although shading in many cases is a solution to maintain the desired microclimate, in the case of photovoltaic installations, the permanent shading of the crop is a challenge, due to the importance of light to the growth, morphogenesis, and other critical physiological processes. In this study, the effect of shade from semi-transparent photovoltaics on a strawberry crop (Fragaria x ananassa Duch.) was examined, in terms of growth and quality (phenolic and flavonoid concentration of fruits). According to the results, in non-shaded plants, there was a trend of larger plants, but without a significant change in leaf number, while the total number of flowers was slightly higher at the end of the cultivation period. Moreover, it was found that the percentage change between the number of ripe fruits was smaller than that of the corresponding change in fruit weight, implying the increased size of the fruits in non-shaded plants. Finally, regarding the antioxidant capacity, it was clearly demonstrated that shading increased the total phenolic content, as well as the free-radical-scavenging activity of the harvested fruits. Although the shading from the semi-transparent photovoltaics did not assist the production of large fruits, it did not affect their number and increased some of their quality characteristics. In addition, the advantageous impact of the semi-transparent photovoltaics in the energy part must not be neglected.

Application of in-situ casted ZnO-starch nanocomposite for packaging of strawberries (Fragaria x ananassa).

Nanomaterials have recently been used in packaging as antibacterial coatings because of their desirable antibacterial and antifungal properties. In this study, we describe the synthesis of zinc oxide nanoparticles (ZnO NPs) and evaluate potato peel starch based ZnO NPs nanocomposite paper (ZnO-starch NC paper) on microbiological activity, storage, and properties of strawberries (Fragaria x ananassa). The ZnO-starch NC paper was used to package the strawberries and then stored at 4 °C and 27 °C for 10 days, respectively, controls were incubated without the ZnO-starch NC paper. The ZnO NPs were synthesized and characterized, the formation of sizes ranging from 35 to 40 nm were confirmed by SEM and XRD. The SEM showed that the ZnO NPs were successfully embedded in the starch forming the ZnO-starch NC. The antimicrobial and antifungal analysis showed that the ZnO-starch NC paper was effective against the fungi, B. cinerea, gram positive bacteria, B. subtilis and S. aureus but not against the gram negative bacteria, E. coli and P. aeruginosa. Total phenolic compounds and Vitamin C content of both the ZnO-starch NC packaged and controls were found to be in the normal range of recommended quality parameters of strawberries as there was no change in intrinsic factors of the fruits during incubation. Application of the ZnO-starch NC in packaged strawberries resulted in the reduction of weight loss and microbial growth compared to the controls. The overall weight loss showed that the loss of moisture and nutrients was not statistically significant (p > 0.05). We conclude that the ZnO-starch NC packaging is a promising safe alternative to extend storage period and increase the shelf-life of strawberries.

Storage of halved strawberry fruits affects aroma, phytochemical content and gene expression, and is affected by pre-harvest factors.

Introduction: Strawberry fruit are highly valued for their aroma which develops during ripening. However, they have a short shelf-life. Low temperature storage is routinely used to extend shelf-life for transport and storage in the supply chain, however cold storage can also affect fruit aroma. Some fruit continue to ripen during chilled storage; however, strawberries are a non-climacteric fruit and hence ripening postharvest is limited. Although most strawberry fruit is sold whole, halved fruit is also used in ready to eat fresh fruit salads which are of increasing consumer demand and pose additional challenges to fresh fruit storage. Methods: To better understand the effects of cold storage, volatilomic and transcriptomic analyses were applied to halved Fragaria x ananassa cv. Elsanta fruit stored at 4 or 8°C for up to 12 days over two growing seasons. Results and discussion: The volatile organic compound (VOC) profile differed between 4 or 8°C on most days of storage. Major differences were detected between the two different years of harvest indicating that aroma change at harvest and during storage is highly dependent on environmental factors during growth. The major component of the aroma profile in both years was esters. Over 3000 genes changed in expression over 5 days of storage at 8°C in transcriptome analysis. Overall, phenylpropanoid metabolism, which may also affect VOCs, and starch metabolism were the most significantly affected pathways. Genes involved in autophagy were also differentially expressed. Expression of genes from 43 different transcription factor (TF) families changed in expression: mostly they were down-regulated but NAC and WRKY family genes were mainly up-regulated. Given the high ester representation amongst VOCs, the down-regulation of an alcohol acyl transferase (AAT) during storage is significant. A total of 113 differentially expressed genes were co-regulated with the AAT gene, including seven TFs. These may be potential AAT regulators.

Optimization of the Extraction Conditions of Antioxidant Phenolic Compounds from Strawberry Fruits (Fragaria x ananassa Duch.) Using Response Surface Methodology.

The subject of this study is to determine the best solvent and optimum extraction conditions for the extraction of maximum antioxidant phenolic compounds and antioxidant activity from strawberry fruits (Fragaria x ananassa Duch.). Extractions were carried out using solvents with different polarities (water, methanol, ethanol, acetonitrile, and acetone). Box-Behnken Design was used to optimize extraction conditions, including extraction time (t), temperature (°C), and liquid/solid (L/S) ratio. In the study, extracts obtained with acetone indicated the highest total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity. The optimal extraction conditions for both responses were determined to be time of 17.5 min, temperature 52.5 °C, and liquid/solid ratio of 30:1. The maximum TPC and TFC values were found as 18.78 ± 0.22 mg of gallic acid equivalent (GAE/g) and 10.52 ± 0.35 mg of catechin equivalents (CE/g) under optimum extraction conditions. The results indicated that optimizing extraction conditions is critical for quantifying antioxidant phenolic compounds. The present model can contribute to finding a cheap way of delivering natural antioxidants in the food, cosmeceutical, and pharmaceutical industries. Furthermore, these results indicate that strawberry fruits (Fragaria x ananassa Duch.) can be a natural food colorant in dietary applications with potential health benefits.

Responses of two strawberry cultivars to NaCl-induced salt stress under the influence of ZnO nanoparticles.

Salinity stress is one of the most serious impacts of climate changes on agriculture production, especially in salt sensitive crop plants, like strawberry. Currently, the utilization of nanomolecules in agriculture is thought to be a useful strategy to compact abiotic and biotic stresses. This study aimed to investigate the effect of zinc oxide nanoparticles (ZnO-NPs) on the in vitro growth, ions uptake, biochemical and anatomical responses of two strawberry cvs (Camarosa and Sweet Charlie) under NaCl-induced salt stress. A 2x3x3 factorial experiment was conducted, with three levels of ZnO-NPs (0, 15 and 30 mg 1-l) and three levels of NaCl-induced salt stress (0, 35 and 70 mM). The results showed that increased levels of NaCl in the medium had led to decrease in shoot fresh weight and proliferative potential. The cv Camarosa was found to be relatively more tolerant to salt stress. Additionally, salt stress leads to an accumulation of toxic ions (Na + and Cl-), as well as a decrease in K + uptake. However, application of ZnO-NPs at a concentration of 15 mg 1-l was found to alleviate these effects by increasing or stabilizing growth traits, decreasing the accumulation of toxic ions and the Na+/K + ratio, and increasing K + uptake. Additionally, this treatment led to elevated levels of catalase (CAT), peroxidase (POD) and proline content. The positive impacts of ZnO-NPs application were reflected on the leaf anatomical features, being better adapted to salt stress. The study highlighted the efficiency of utilizing tissue culture technique in screening of strawberry cultivars for salinity tolerance under the influence of NPs.

Strawberry Fragaria x ananassa cv. Festival: A Polyphenol-Based Phytochemical Characterization in Fruit and Leaf Extracts.

Berry fruits are an important dietary source of health-promoting antioxidant polyphenols. Interestingly, berry leaves of diverse species, including strawberries, have shown higher bioactive phytochemical content in the leaves than in the fruit. Moreover, the vegetative part of the plants is usually discarded, representing a presumably large source of underutilized bioactive biomass. In this investigation, the polyphenol profiles of tropical highland strawberry (Fragaria x ananassa cv. Festival) leaves and fruits were compared by high-performance liquid chromatography coupled with a diode array detector (UHPLC-DAD) and mass spectrometry (HPLC-MS). The total polyphenol strawberry leaf extracts exhibited a 122-fold-higher total polyphenol content and 13-fold higher antioxidant activity (ORAC) than strawberry fruits, and they showed evidence of possible photoprotective effects against UV damage in human melanoma cells (SK-MEL-28) and in murine embryo fibroblasts (NIH/3T3), together with promising anti-proliferative activities against the same melanoma cells. Seven polyphenols were confirmed by HPLC-DAD in the leaf extracts, with differences depending on fraction solubility. Moreover, three substituted quercetin derivatives, three substituted kaempferol derivatives, two anthocyanins, and catechin were confirmed in the soluble fraction by HPLC-MS. Given their higher total polyphenol content and bioactive activities, underutilized strawberry Festival leaves are a potential source of apparently abundant biomass with prospective bioactive applications.

Leaf Nutrient Status of Commercially Grown Strawberries in Latvia, 2014-2022: A Possible Yield-Limiting Factor.

The present study was carried out to evaluate the leaf nutrient status of commercially grown strawberries in Latvia during 2014-2022. The results of N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, Mo and B in 200 strawberry leaf samples from different strawberry-producing farms were analysed over three periods: 2014-2016, 2017-2019, and 2020-2022. According to leaf analyses, plant fertilization was only partly well managed by the growers. During the research period, strawberries in Latvia were generally sufficiently supplied with N, P, K, Mg, Fe, Mn, Mo, and B, while the level of Ca, S, Zn, and Cu was considered low. The deficiency of these nutrients was characteristic for more than 50% of the samples. Since Ca, S, Zn, and Cu are essential for berry formation and quality and contribute to stress resistance; their deficiency could be one of the limiting factors for strawberry yield. The significant positive correlations found between nutrients, including deficient ones, confirmed their close relationship in the uptake process and the importance of sufficient supply. The results clearly indicated that fertilization could currently be an issue that limits the strawberry harvest in Latvia, and adequate provisions of Ca, S, Zn, and B should be the main focus.

Reuse of coir, peat, and wood fiber in strawberry production.

Introduction: Production of strawberries in greenhouses and polytunnels is gaining popularity worldwide. This study investigated the effect of reuse of coir and peat, two substrates commonly adapted to soilless strawberry production, as well as stand-alone wood fiber from Norway spruce, a promising substrate candidate. Methods: The experiment was performed in a polytunnel at NIBIO Apelsvoll, Norway, and evaluated both virgin substrates, as well as spent materials that were used in one or two years. Yield, berry quality and plant architecture of the strawberry cultivar 'Malling Centenary' were registered. In addition, chemical and physical properties of virgin and reused substrates were investigated. Results: While plants grown in peat and wood fiber had highest yield in the first year of production, the berry yield was slightly reduced when these substrates were utilized for the second and third time. However, yield was comparable to the yield level attained in new and reused coir. Interestingly, berries grown in wood fiber had a tendency to a higher sugar accumulation. This substrate also produced the highest plants. Stand-alone wood fiber was the substrate with the highest accumulation of nitrogen during the three consecutive production cycles. All three investigated materials revealed a trend for decreased potassium accumulation. Wood fiber is characterized by the highest percentage of cellulose, however after three years of production the cellulose content was reducedto the same levels as for coir and peat. Discussion: Implementation of wood fiber as a growing medium, as well as general practice of substrate reuse can be therefore an achievable strategy for more sustainable berry production.

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.

Heterozygous frameshift mutation in FaMYB10 is responsible for the natural formation of red and white-fleshed strawberry (Fragaria x ananassa Duch).

During natural evolution and artificial selection, the fruit color of many species has been repeatedly gained or lost and is generally associated with mutations in genes encoding R2R3-MYB transcription factors, especially MYB10. In this study, we show that a heterozygous frameshift mutation (FaMYB10AG-insert/FaMYB10wild ) is responsible for the loss of anthocyanins in the flesh of cultivated strawberry. Comparative transcriptomic and metabolomic analyses of red- and white-fleshed strawberry indicated that the low expression level of FaUFGT (flavonol-O-glucosyltransferases) was responsible for the loss of anthocyanins and accumulation of proanthocyanidin in the white-fleshed strawberry and was the crucial gene that encodes enzymes of the anthocyanin biosynthesis pathway. Accordingly, overexpression and silencing of FaUFGT altered anthocyanin content and changed the flesh color of strawberry fruits. Furthermore, whole-genome resequencing analyses identified an AG insertion in the FaMYB10 coding region (FaMYB10AG-insert ) of white-fleshed strawberry. Y1H and EMSA assays showed that FaMYB10wild was able to bind to the promoter of the FaUFGT gene, while the FaMYB10AG-insert could not. The skin and flesh color were tightly linked to the number of fully functional FaMYB10 copies in the selfing progeny of white-fleshed strawberry. Our results suggested that heterozygous frameshift mutation of FaMYB10 resulted in the loss of the ability to activate the expression of the FaUFGT gene, was responsible for the natural formation of red and white-fleshed strawberry.

Genotype, mycorrhizae, and herbivory interact to shape strawberry plant functional traits.

Arbuscular mycorrhizal fungi (AMF) and herbivores are ubiquitous biotic agents affecting plant fitness. While individual effects of pairwise interactions have been well-studied, less is known about how species interactions above and belowground interact to influence phenotypic plasticity in plant functional traits, especially phytochemicals. We hypothesized that mycorrhizae would mitigate negative herbivore effects by enhancing plant physiology and reproductive traits. Furthermore, we expected genotypic variation would influence functional trait responses to these biotic agents. To test these hypotheses, we conducted a manipulative field-based experiment with three strawberry (Fragaria x ananassa) genotypes to evaluate plant phenotypic plasticity in multiple functional traits. We used a fully-crossed factorial design in which plants from each genotype were exposed to mycorrhizal inoculation, herbivory, and the combined factors to examine effects on plant growth, reproduction, and floral volatile organic compounds (VOCs). Genotype and herbivory were key determinants of phenotypic variation, especially for plant physiology, biomass allocation, and floral volatiles. Mycorrhizal inoculation increased total leaf area, but only in plants that received no herbivory, and also enhanced flower and fruit numbers across genotypes and herbivory treatments. Total fruit biomass increased for one genotype, with up to 30-40% higher overall yield depending on herbivory. Herbivory altered floral volatile profiles and increased total terpenoid emissions. The effects of biotic treatments, however, were less important than the overall influence of genotype on floral volatile composition and emissions. This study demonstrates how genotypic variation affects plant phenotypic plasticity to herbivory and mycorrhizae, playing a key role in shaping physiological and phytochemical traits that directly and indirectly influence productivity.

Unravelling the Effect of Triacontanol in Combating Drought Stress by Improving Growth, Productivity, and Physiological Performance in Strawberry Plants.

To explore the effects of triacontanol (TR) on drought tolerance of strawberry plants (cv Fertona), two field experiments were carried out to study the effects of three supplementary foliar TR rates (0, 0.5, and 1 ppm) under the following three levels of water irrigation: 11 m3/hectare (40% of water holding capacity (WHC) severe as a drought treatment, 22 m3/hectare (80% of WHC) as moderate drought stress, and normal irrigation with 27 m3/hectare (100% of WHC) server as a control treatment. TR treatments were applied five times after 30 days from transplanting and with 15-day intervals. The results showed that drought stress (40% and 80%) markedly decreased the growth, fruit yield, and chlorophyll reading, as well as the gas exchange parameters (net photosynthetic rate, stomatal conductance, and transpiration rate). Meanwhile, drought stress at a high rate obviously increased antioxidant enzyme activities such as superoxide dismutase (SOD), peroxidase (POX), and catalase (CAT) contents in the leaves of the strawberry plants. The moderate and high drought stress rates enhanced some strawberry fruit quality parameters such as total soluble solids (TSS), vitamin C, and anthocyanin content compared to the control. Additionally, TR increased the activities of SOD, POX, and CAT. TR treatment significantly increased the chlorophyll contents, gas exchange parameters (photosynthetic rate and stomatal conductance), and water use efficiency (WUE). Plant height, fruit weight, and total biomass were increased also via TR application. Total yield per plant was increased 12.7% using 1 ppm of TR compared with the control. In conclusion, our results suggested that TR application could relieve the adverse effects of drought stress on the growth of strawberry plants by enhancing the antioxidant enzymes, photosynthesis rate, and WUE of the leaves.

Co-pigmentation of strawberry anthocyanins with phenolic compounds from rooibos.

Anthocyanin-rich strawberry model solutions were co-pigmented with rooibos phenolics to enhance color and heat stability. The addition of green and fermented rooibos extracts at pigment-to-co-pigment molar ratios of 1:10, 1:50, and 1:100 pelargonidin-3-glucoside equivalents: orientin equivalents induced hyper- and bathochromic shifts at room temperature and during thermal processing at 80 °C for an hour. Co-pigmentation effects on hyperchromic shift were up to 96%, and bathochromic shift reached 19 nm when adding flavonoid-rich fractions of green rooibos phenolics. Following the co-pigmentation tests with rooibos extracts, selected pure phenolic co-pigments were tested for their monomeric contribution to the observed co-pigmentation effects. Orientin was identified as a potent co-pigment for pelargonidin-3-glucoside, showing stronger co-pigmentation effects than that of its aglycon luteolin. Additionally, orientin had the most pronounced bathochromic shift in heat-treated solutions. Rooibos extracts, particularly flavonoid-rich fractions composed of luteolin, apigenin, and quercetin glycosides, are suggested as color enhancers and stabilizers for strawberry products.

Green synthesis of silver nanoparticles with Euphorbia tirucalli extract and its protection against microbial decay of strawberries during storage.

Silver nanoparticles (AgNPs) can be produced through an easy and safe process called green synthesis and have been considered an efficient antimicrobial agent. The antimicrobial effect of silver nanoparticles green synthesized with E. tirucalli (aveloz) can be a promising technique for preserving stored strawberries. The objective of this work was to perform a green synthesis of AgNPs with aveloz extract (Av) and evaluate its effect on the physiology and preservation of stored strawberries. Silver nitrate was reduced with Av to produce Av-AgNPs. The Av-AgNPs were characterized by Scanning Electron Microscope, Energy Dispersive X-ray Spectrometry, and laser diffraction. The in vitro antifungal activity of Av-AgNPs was evaluated against Botrytis cinerea and Rhizopus stolonifer. Strawberries were treated with Av-AgNPs and stored (5 °C) for 12 days. Respiratory rate, decay, fresh mass loss, firmness, total phenolics and antioxidant activity of the strawberries were evaluated. According to the results, Av-AgNPs synthesis was performed, and it presented sizes between 40 and 90 nm. Av-AgNPs inhibited B. cinerea but was less effective for R. stolonifer. Total phenolic compounds, antioxidant activity, fresh mass loss and firmness of strawberries were not influenced by Av-AgNPs. Treated strawberries had a lower respiratory rate than the control and showed no symptoms of microbiological deterioration until 9 days of storage, while in the control the deterioration symptoms started after 3 days. This study showed that the green synthesis of AgNPs with Av produced nanoparticles smaller than 100 nm, and that they were effective against strawberries decay during storage, indicating to be a promising protection technique against decay.

First report of Cercospora cf. malloti causing brown eyespot on strawberry in Brazil.

Strawberry (Fragaria x ananassa Duch.) is one of the most consumed fruits from the Rosaceae family in Brazil. It is cultivated on ~4,500 ha in all regions of the country, with a wide range of fungi causing leaf diseases. Strawberry leaves (cv. San Andreas) with symptoms of eyespot usually related to Mycosphaerella fragariae (Ramularia tulasnei) (Mazaro et al. 2006) were observed in April 2019, in a field located in Santa Maria, Rio Grande do Sul state, Brazil (29°43'19.6"S / 53°43'04.6"W). However, the symptoms slightly differed from Mycospherella blight as well as the fungi structures observed under an optical microscope. The symptomatic leaves had small circular spots, initially reddish-purple to dark brown color, which later increased in size. The center of the lesion was grayish pale, where dark brown conidiophores were found over it. The symptom occurred in 50% of the leaves of all plants during the crop season. To identify the causal agent, symptomatic leaves were collected and superficially disinfected with 70% ethanol for 30 s followed by 0.5% bleach for 30 s and then washed in sterile water. The leaves were placed in germination boxes with a moistened paper filter and incubated at 25 ºC and 12 h photoperiod for four days. After the formation of the fungal structures, the fungi was isolated in potato dextrose agar (PDA) medium and kept for 20 days at 25 ºC. Colonies were dark brown with pale pink aerial mycelium. The conidia were hyaline, single- to multi-septated with a filiform shape, straight or slightly curved. The fasciculate conidiophores on the stroma measured 20 to 70 x 2.5 to 3.5 µm. Conidia average measurement was 10.2 to 82.4 x 4. to 8.8 µm, similar to morphological characteristics of the genus Cercospora. The isolate named M6 was deposited in the Brazilian National System of Genetic Registration (SISGEN) no A57AE19. The DNA was extracted from a monosporic culture of M6 in PDA plates, which presented all typical aspects previously described. To confirm the identity, the PCR amplification was carried out for internal transcribed spacer (ITS) region ITS 1-5.8S - ITS 2 and Calmodulin region (CAL) genes (Acqua et al, 2011). The ITS (No. MZ713249) and CAL (No. MZ713254) sequences were deposited in the Genbank database. BLASTn analysis revealed the isolate was 99% similar to Cercospora cf. malloti which access codes in GenBank are KT 193689 and KT 193738 (Nguanhom et al. 2015). A pathogenicity test was performed to fulfill Koch's postulates. Strawberry plants with healthy leaves (60 days old), were inoculated by spraying a conidial suspension (1 × 105 conidia/ml). Control plants were sprayed with sterile water. The plants were incubated in a greenhouse at 28 ºC for 12 h photoperiod at 80% relative humidity under drip irrigation keeping at least 60% of field capacity. Six plants were used as replicates. Twenty days after inoculation, small circular reddish-purple spots were found, which later increased in size. Ten days later, the spots presented dark brown conidiophores over the center of the lesion. The symptoms described above were observed in all inoculated leaves. The control plants remained symptom-free. The pathogen was then re-isolated from the lesions and identified as C. cf. malloti based on the morphological aspects described above on PDA. In Thailand C. cf. malloti is reported on crops like Brassica alboglabra (cabbage) (Nguanhom et al. 2015), but not in strawberries. To our knowledge, this is the first report of C. cf. malloti pathogenic to strawberries in Brazil.

Acarofauna present in organic strawberry fields and associated weed species in southern Brazil.

The presence of weeds in the margins of strawberry crops can enhance populations of predatory mites as a measure to support conservation biological control. The aims of this study were (i) to assess the composition of the acarofauna associated with strawberries and the accompanying herbaceous plants in an organic farming system, and (ii) to evaluate the possible relationships between phytophagous and predatory mites occurring in this system. Strawberry leaves and whole plants of weeds were sampled biweekly from August 2014 to February 2015 in Lapa (Paraná, Brazil). In total, 23 weed species belonging to 10 families were identified; 3768 mite individuals (from 15 families and 4 suborders) were recovered, 77% on strawberries and 23% on weeds. Abundance of predatory mites on weeds was greater than on strawberry cultivars. On strawberries, the most abundant family was Tetranychidae (84%) followed by Phytoseiidae (11.6%). In total, 16 predatory mite species from the Phytoseiidae family were identified, 13 of them occurring on strawberry leaflets. Typholodromalus aripo, Neoseiulus californicus and Typhlodromips mangleae were the most abundant mite species on strawberry leaves. On weeds, most individuals were predatory mites (59%), whereas phytophagous mites represented 17.2%. The most abundant family was Phytoseiidae (36.4%). On weeds, the phytoseiid mite T. aripo was the most abundant species, representing 34.7%. Besides being found on strawberry leaflets, T. aripo was associated with 15 weed species. Among the weeds, Bidens pilosa showed the highest values of the Shannon index (1.97), Margalef index (3.04), and Pielou's evenness index (0.95). This study emphasizes the importance of surrounding weeds as a shelter for beneficial mitefauna in strawberry fields, likely contributing to enhance conservation biological control.

Seasonal Variation of Plant Defense Inductor Ellagitannins in Strawberry Leaves under Field Conditions for Phytosanitary Technological Applications.

Many natural compounds can activate the plant immunity, and for this reason, they have attracted special interest in crop disease management. Previously, we isolated from strawberry leaves an ellagitannin (HeT), which elicits plant defense responses. In this research, we investigated bioactive compounds from field-collected strawberry leaves capable of inducing defense responses in Arabidopsis thaliana against a bacterial pathogen. Methanolic extracts of strawberry leaves sampled at different months were obtained and compared. The highest content of total soluble phenolic compounds was found in the methanolic extracts of leaves sampled in December (DME). The defense response induced in A. thaliana by DME was attributed to two ellagitannins, the HeT and galloyl-HHDP-glucose. Both compounds exhibited phytoprotective effects against Pseudomonas viridiflava and induced the expression of PDF1.2 and PR1 genes. These results provide an economic value to strawberry leaves, normally discarded at the end of the harvest stage of the crop, as a raw material for plant health enhancer bioinputs.

Shape, firmness and fruit quality QTLs shared in two non-related strawberry populations.

The cultivated strawberry (Fragaria x ananassa) is an octoploid species (2n = 8x = 56), appreciated widely for its fruit. There have been very few studies on fruit quality traits, which are known to be mostly polygenic and environmentally dependent. To identify higher genetic variability, two non-related populations were genotyped: an F1 population cross between 'FC50' and 'FD54' and an F2 population cross between 'Camarosa' and 'Dover', hybridizing both with IStraw35k and IStraw90k SNP arrays, respectively. The F1 genetic map was constructed with 14595 SNPs and the F2 map with 7977 SNPs. High collinearity was observed when comparing one genetic map with the other and on comparing both with the octoploid genome. To assess fruit variability, both populations were phenotyped for shape, firmness, taste and other fruit traits over the 2016-2019 period. With QTL analyses, 33 stable QTLs were mapped in the 'FC50xFD54' population, and three hotspot regions were found for shape traits in LG3A, LG4D and LG6D. In the '21AF' population, only eight stable QTLs were detected. Despite that, two major and stable QTLs were mapped in the same interval of confidence for both populations. A shared fruit shape ratio QTL which explained around 25 % of trait variance was mapped in LG3A, and a shared firmness QTL explaining 26.9 % of trait variance in LG7C. For the first time, two QTLs were discovered in LG3A and LG4A for a phenotype neck without achenes. When analysing two different mapping populations, in addition to finding specific QTL regions for the studied traits, a narrowing down of the interval of confidence for the shared QTLs is achieved. As a result of this study, a new set of SNPs for fruit firmness and shape is now available for use in MAS in strawberry breeding programs.

First Report of Colletotrichum karstii Causing Anthracnose on Strawberry in Brazil.

Strawberry (Fragaria x ananassa Duch.) is one of the most important fruit crops worldwide. With increasing cultivated area in the last decades, Brazil has become the largest strawberry producer in South America. Anthracnose caused by Colletotrichum spp. has been considered one of the most destructive diseases in Brazil. In May 2019, irregular and circular dark brown leaf spots sometimes associated with chlorosis and petiole necrosis were observed on strawberry plants (cv. Pircinque) organically cultivated in Santa Catarina state, Brazil (27°45'40"S, 49°59'06''W). The Colletotrichum isolate was obtained from leaf, and monosporic culture was grown on potato dextrose agar at 25°C and 12-h photoperiod under near ultraviolet light. Colonies at the age of 15 days showed upper surface color varying from white to orange and the reverse side grayish to orange. Conidia were hyaline, cylindrical with rounded ends, 13.9 to 9.2 × 4.2 to 6.7 µm ((x ) ̅= 11.3 × 5.2, n = 100). Perithecia were produced in vitro and their diameter ranged from 265.2 to 142.5 µm ((x ) ̅= 198.4). Asci were 47.3 to 39.9 × 5.2 to 7.2 µm ((x ) ̅= 42.8 × 5.9, n = 50), and ascospores 12.6 to 8.1 × 4.3 to 2.1 ((x ) ̅= 10.3 × 2.9, n = 100). To confirm pathogenicity, 90-day-old plants of strawberry (cv. Pircinque) were inoculated by spraying a suspension of 1×106 conidia/ml, incubated in a moist chamber in the dark for 48 h and then kept in a greenhouse for further 30 days. Plants sprayed with sterile distilled water served as control. Additionally, detached leaves were inoculated with six drops of 10 µl (1×106 conidia/ml) onto abaxial surface and incubated in a moist chamber at 25°C and 12 h photoperiod for 15 days. Inoculated plants exhibited first symptoms in both leaves and petioles at 15 days after inoculation (dai). On leaf, irregular and circular dark brown spots evolved to necrotic lesions and were frequently surrounded by chlorotic halos. In petioles, lesions were reddish-brown, elongated, and depressed. Typical anthracnose symptoms on fruits at 6 dai showed as circular, slightly sunken lesions that enlarged over time and produced an abundant orange mucilaginous mass of acervuli and conidia, and after 20 days, fruits became mummified. In the detached-leaf-assay, symptoms appeared at 7 dai, with presence of circular dark brown lesions measuring 1 to 15 mm and then evolved to necrosis. The same pathogen was consistently re-isolated from the inoculated leaves, petioles, and fruits, and confirmed by morphological characterization and molecular assays as described in this note. A representative isolate (MANE189) was molecularly identified using genomic regions of actin (ACT), ß-tubulin (TUB2), calmodulin (CAL), glyceraldehyde-3-phosphate-dehydrogenase (GAPDH), glutamine synthetase (GS), and internal transcribed spacer (ITS). Nucleotide sequences exhibited 100% homology to the typical Colletotrichum karstii strains (CBS:127535, CBS:128500 and ML1792) and were deposited in GenBank database (MW396420, MW396430, MW396460, MW396440, MW396450, and MW331606). This species belongs to the C. boninense species complex (Damm et al. 2012) and was previoStrawberry (Fragaria x ananassa Duch.) is one of the most important fruit crops worldwide. With increasing cultivated area in the last decades, Brazil has become the largest strawberry producer in South America. Anthracnose caused by Colletotrichum spp. has been considered one of the most destructive diseases in Brazil. In May 2019, irregular and circular dark brown leaf spots sometimes associated with chlorosis and petiole necrosis were observed on strawberry plants (cv. Pircinque) organically cultivated in Santa Catarina state, Brazil (27°45'40"S, 49°59'06''W). The Colletotrichum isolate was obtained from leaf, and monosporic culture was grown on potato dextrose agar at 25°C and 12-h photoperiod under near ultraviolet light. Colonies at the age of 15 days showed upper surface color varying from white to orange and the reverse side grayish to orange. Conidia were hyaline, cylindrical with rounded ends, 13.9 to 9.2 × 4.2 to 6.7 µm ((x ) ̅= 11.3 × 5.2, n = 100). Perithecia were produced in vitro and their diameter ranged from 265.2 to 142.5 µm ((x ) ̅= 198.4). Asci were 47.3 to 39.9 × 5.2 to 7.2 µm ((x ) ̅= 42.8 × 5.9, n = 50), and ascospores 12.6 to 8.1 × 4.3 to 2.1 ((x ) ̅= 10.3 × 2.9, n = 100). To confirm pathogenicity, 90-day-old plants of strawberry (cv. Pircinque) were inoculated by spraying a suspension of 1×106 conidia/ml, incubated in a moist chamber in the dark for 48 h and then kept in a greenhouse for further 30 days. Plants sprayed with sterile distilled water served as control. Additionally, detached leaves were inoculated with six drops of 10 µl (1×106 conidia/ml) onto abaxial surface and incubated in a moist chamber at 25°C and 12 h photoperiod for 15 days. Inoculated plants exhibited first symptoms in both leaves and petioles at 15 days after inoculation (dai). On leaf, irregular and circular dark brown spots evolved to necrotic lesions and were frequently surrounded by chlorotic halos. In petioles, lesions were reddish-brown, elongated, and depressed. Typical anthracnose symptoms on fruits at 6 dai showed as circular, slightly sunken lesions that enlarged over time and produced an abundant orange mucilaginous mass of acervuli and conidia, and after 20 days, fruits became mummified. In the detached-leaf-assay, symptoms appeared at 7 dai, with presence of circular dark brown lesions measuring 1 to 15 mm and then evolved to necrosis. The same pathogen was consistently re-isolated from the inoculated leaves, petioles, and fruits, and confirmed by morphological characterization and molecular assays as described in this note. A representative isolate (MANE189) was molecularly identified using genomic regions of actin (ACT), ß-tubulin (TUB2), calmodulin (CAL), glyceraldehyde-3-phosphate-dehydrogenase (GAPDH), glutamine synthetase (GS), and internal transcribed spacer (ITS). Nucleotide sequences exhibited 100% homology to the typical Colletotrichum karstii strains (CBS:127535, CBS:128500 and ML1792) and were deposited in GenBank database (MW396420, MW396430, MW396460, MW396440, MW396450, and MW331606). This species belongs to the C. boninense species complex (Damm et al. 2012) and was previously reported causing anthracnose on strawberry leaves in Taiwan (Chung et al. 2020). To our knowledge, this is the first report of C. karstii causing anthracnose on strawberry in Brazil. The accurate identification of the pathogen will assist in the disease management and resistance breeding. usly reported causing anthracnose on strawberry leaves in Taiwan (Chung et al. 2020). To our knowledge, this is the first report of C. karstii causing anthracnose on strawberry in Brazil. The accurate identification of the pathogen will assist in the disease management and resistance breeding.

Strawberry-Derived Exosome-Like Nanoparticles Prevent Oxidative Stress in Human Mesenchymal Stromal Cells.

Plant-derived exosome-like nanovesicles (EPDENs) have recently been isolated and evaluated as potential bioactive nutraceutical biomolecules. It has been hypothesized that EPDENs may exert their activity on mammalian cells through their specific cargo. In this study, we isolated and purified EPDENs from the strawberry juice of Fragaria x ananassa (cv. Romina), a new cultivar characterized by a high content of anthocyanins, folic acid, flavonols, and vitamin C and an elevated antioxidant capacity. Fragaria-derived EPDENs were purified by a series of centrifugation and filtration steps. EPDENs showed size and morphology similar to mammalian extracellular nanovesicles. The internalization of Fragaria-derived EPDENs by human mesenchymal stromal cells (MSCs) did not negatively affect their viability, and the pretreatment of MSCs with Fragaria-derived EPDENs prevented oxidative stress in a dose-dependent manner. This is possibly due to the presence of vitamin C inside the nanovesicle membrane. The analysis of EPDEN cargo also revealed the presence of small RNAs and miRNAs. These findings suggest that Fragaria-derived EPDENs may be considered nanoshuttles contained in food, with potential health-promoting activity.