Seasonal Dynamics and Distribution of Xylella fastidiosa in Infected Almond Trees.

This research focused on studying the dynamics of the bacterial pathogen Xylella fastidiosa in almond trees across different developmental stages. The objective was to understand the seasonal distribution and concentration of X. fastidiosa within almond trees. Different tree organs, including leaves, shoots, branches, fruits, flowers, and roots, from 10 X. fastidiosa-infected almond trees were sampled over 2 years. The incidence and concentration of X. fastidiosa were determined using qPCR and isolation. Throughout the study, X. fastidiosa was consistently absent from fruits, flowers, and roots, whereas it was detected in leaves as well as in shoots and branches. We demonstrate that the absence of X. fastidiosa in the roots is likely linked to the inability of this isolate to infect the peach-almond hybrid rootstock GF677. X. fastidiosa incidence in shoots and branches remained consistent throughout the year, whereas in leaf petioles, it varied across developmental stages, with lower detection during the early and late stages of the season. Similarly, viable X. fastidiosa cells were isolated from shoots and branches at all developmental stages, but no successful isolations were achieved from leaf petioles during the vegetative and nut growth stage. Studying the progression of almond leaf scorch symptoms in trees with initial infections showed that once symptoms emerged on one branch, symptomless branches were likely already infected by the bacterium. Therefore, selectively pruning symptomatic branches is unlikely to cure the tree. This study enhances our understanding of X. fastidiosa dynamics in almond trees and may have practical applications for its detection and control.

Performance of Outbreak Management Plans for Emerging Plant Diseases: The Case of Almond Leaf Scorch Caused by Xylella fastidiosa in Mainland Spain.

Outbreak response to quarantine pathogens and pests in the European Union (EU) is regulated by the EU Plant Health Law, but the performance of outbreak management plans in terms of their effectiveness and efficiency has been quantified only to a limited extent. As a case study, the disease dynamics of almond leaf scorch, caused by Xylella fastidiosa, in the affected area of Alicante, Spain, were approximated using an individual-based spatial epidemiological model. The emergence of this outbreak was dated based on phylogenetic studies, and official surveys were used to delimit the current extent of the disease. Different survey strategies and disease control measures were compared to determine their effectiveness and efficiency for outbreak management in relation to a baseline scenario without interventions. One-step and two-step survey approaches were compared with different confidence levels, buffer zone sizes, and eradication radii, including those set by the EU legislation for X. fastidiosa. The effect of disease control interventions was also considered by decreasing the transmission rate in the buffer zone. All outbreak management plans reduced the number of infected trees (effectiveness), but large differences were observed in the number of susceptible trees not eradicated (efficiency). The two-step survey approach, high confidence level, and the reduction in the transmission rate increased the efficiency. Only the outbreak management plans with the two-step survey approach removed infected trees completely, but they required greater survey efforts. Although control measures reduced disease spread, surveillance was the key factor in the effectiveness and efficiency of the outbreak management plans. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Ten Challenges to Understanding and Managing the Insect-Transmitted, Xylem-Limited Bacterial Pathogen Xylella fastidiosa.

An unprecedented plant health emergency in olives has been registered over the last decade in Italy, arguably more severe than what occurred repeatedly in grapes in the United States in the last 140 years. These emergencies are epidemics caused by a stealthy pathogen, the xylem-limited, insect-transmitted bacterium Xylella fastidiosa. Although these epidemics spurred research that answered many questions about the biology and management of this pathogen, many gaps in knowledge remain. For this review, we set out to represent both the U.S. and European perspectives on the most pressing challenges that need to be addressed. These are presented in 10 sections that we hope will stimulate discussion and interdisciplinary research. We reviewed intrinsic problems that arise from the fastidious growth of X. fastidiosa, the lack of specificity for insect transmission, and the economic and social importance of perennial mature woody plant hosts. Epidemiological models and predictions of pathogen establishment and disease expansion, vital for preparedness, are based on very limited data. Most of the current knowledge has been gathered from a few pathosystems, whereas several hundred remain to be studied, probably including those that will become the center of the next epidemic. Unfortunately, aspects of a particular pathosystem are not always transferable to others. We recommend diversification of research topics of both fundamental and applied nature addressing multiple pathosystems. Increasing preparedness through knowledge acquisition is the best strategy to anticipate and manage diseases caused by this pathogen, described as "the most dangerous plant bacterium known worldwide."

Prunus dulcis response to novel defense elicitor peptides and control of Xylella fastidiosa infections.

KEY MESSAGE: New defense elicitor peptides have been identified which control Xylella fastidiosa infections in almond. Xylella fastidiosa is a plant pathogenic bacterium that has been introduced in the European Union (EU), threatening the agricultural economy of relevant Mediterranean crops such as almond (Prunus dulcis). Plant defense elicitor peptides would be promising to manage diseases such as almond leaf scorch, but their effect on the host has not been fully studied. In this work, the response of almond plants to the defense elicitor peptide flg22-NH2 was studied in depth using RNA-seq, confirming the activation of the salicylic acid and abscisic acid pathways. Marker genes related to the response triggered by flg22-NH2 were used to study the effect of the application strategy of the peptide on almond plants and to depict its time course. The application of flg22-NH2 by endotherapy triggered the highest number of upregulated genes, especially at 6 h after the treatment. A library of peptides that includes BP100-flg15, HpaG23, FV7, RIJK2, PIP-1, Pep13, BP16-Pep13, flg15-BP100 and BP16 triggered a stronger defense response in almond plants than flg22-NH2. The best candidate, FV7, when applied by endotherapy on almond plants inoculated with X. fastidiosa, significantly reduced levels of the pathogen and decreased disease symptoms. Therefore, these novel plant defense elicitors are suitable candidates to manage diseases caused by X. fastidiosa, in particular almond leaf scorch.

First report of nut rot caused by Botryosphaeria dothidea on almond in Italy.

Almond (Prunus dulcis) is an important nut crop widely grown in the Mediterranean region, including Italy. In September 2021, almonds cv. Tuono showing dark lesions affecting the hull were collected in Villar San Costanzo (Piedmont, Northwestern Italy). The occurrence of symptoms in the orchard was estimated at 50% incidence. Two samples, each consisting of 50 fruits, were collected from the affected orchard. Small sections taken from the margins of the lesions were surface disinfected with 1% sodium hypochlorite for 1 min, rinsed in sterile water, dried on sterile filter paper, and placed on potato dextrose agar (PDA, VWR International, Leuven, Belgium), amended with streptomycin sulfate (25 mg/l) to inhibit bacterial growth. Plates were incubated at 25°C for 7 days under 12-h photoperiod. Botryosphaeria-like fungi were isolated with a frequency of 60%. Two representative isolates (21-06-F1A; 21-06-F4) were transferred onto new PDA plates to obtain pure cultures. Fungal colonies initially appeared white, then gradually turned dark grey and black in reverse as the colony aged. Abundant aerial mycelium was produced. Globose black pycnidia were produced on water agar supplemented with sterile pine needles (PNA; Smith et al. 1996) after 30 days of incubation at 25 ± 1°C under 12-h photoperiod. Conidia were one-celled, hyaline, elliptical, aseptate, 17.46 to 27.05 µm (average 23.51) long and 5.70 to 9.40 µm (average 7.48) wide (n = 50). Morphologically, the causal agent was identified as Botryosphaeria sp. Genomic DNA was extracted from the isolates using the E.Z.N.A. Fungal DNA mini kit (Omega Bio-Tek, Norcross, GA, USA) according to manufacturer instructions. The rDNA internal transcribed spacer (ITS), the partial translation elongation factor 1-alpha gene (tef-1α) and the partial beta-tubulin gene (tub2) were amplified and sequenced using primers ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999), Bt2a/Bt2b (Glass and Donaldson 1995), respectively. BLAST analysis showed 100% identity of the obtained ITS sequences (GenBank accession nos. PP859471, PP859472), tub2 sequences (PP889527, PP889528) and tef-1α sequences (PP889529, PP889530) with those of the ex-type strain of B. dothidea (CBS 115476). The maximum likelihood method based on combined sequences of ITS, tef-1α and tub2 was performed, and both isolates clustered with high bootstrap support values (96) with the ex-type strain of B. dothidea. Pathogenicity was tested on fruits of almond cv Tuono inoculated on tree in a commercial orchard. Ten fruits were randomly chosen and inoculated for each isolate. Inoculation was performed by removing a piece of hull with a sterile cork borer (6 mm diameter) and applying mycelium plugs of the same diameter, taken from 7-day-old colonies grown on PDA, upside-down onto the wounds. Each fruit was inoculated with one mycelium plug and sealed with parafilm. Control fruits were inoculated with sterile PDA plugs. Dark lesions with softening pulp developed on inoculated almonds after 9 days. The mean diameter of the lesions was 3.89 ± 0.80 cm on almonds inoculated with the strain 21-06-F1A and 3.08 ± 0.56 cm on fruits inoculated with the strain 21-06-F4. The pathogen was successfully reisolated and morphologically identified as B. dothidea, fulfilling Koch's postulates. No symptoms were found on control fruits. Botryosphaeria dothidea was previously reported to affect other nut crops, causing nut rot on walnut (Li et al. 2023) and panicle and shoot blight on pistachio (Gusella et al. 2022). To the best of our knowledge, this is the first report of B. dothidea causing nut rot on almond in Italy.

Almond Can Be Infected by Plum Pox Virus-D Isolate Penn4 and Is a Transmission-Competent Host.

Although it is currently eradicated from the United States, Plum pox virus (PPV) poses an ongoing threat to U.S. stone fruit production. Although almond (Prunus dulcis) is known to be largely resistant to PPV, there is conflicting evidence about its potential to serve as an asymptomatic reservoir host for the virus and thus serve as a potential route of entry. Here, we demonstrate that both Tuono and Texas Mission cultivars can be infected by the U.S. isolate PPV Dideron (D) Penn4 and that Tuono is a transmission-competent host, capable of serving as a source of inoculum for aphid transmission of the virus. These findings have important implications for efforts to keep PPV out of the United States and highlight the need for additional research to test the susceptibility of almond to other PPV-D isolates.

Predictive Neural Network Modeling for Almond Harvest Dust Control.

This study introduces a neural network-based approach to predict dust emissions, specifically PM2.5 particles, during almond harvesting in California. Using a feedforward neural network (FNN), this research predicted PM2.5 emissions by analyzing key operational parameters of an advanced almond harvester. Preprocessing steps like outlier removal and normalization were employed to refine the dataset for training. The network's architecture was designed with two hidden layers and optimized using tanh activation and MSE loss functions through the Adam algorithm, striking a balance between model complexity and predictive accuracy. The model was trained on extensive field data from an almond pickup system, including variables like brush speed, angular velocity, and harvester forward speed. The results demonstrate a notable predictive accuracy of the FNN model, with a mean squared error (MSE) of 0.02 and a mean absolute error (MAE) of 0.01, indicating high precision in forecasting PM2.5 levels. By integrating machine learning with agricultural practices, this research provides a significant tool for environmental management in almond production, offering a method to reduce harmful emissions while maintaining operational efficiency. This model presents a solution for the almond industry and sets a precedent for applying predictive analytics in sustainable agriculture.

Development of Loop-Mediated Isothermal Amplification (LAMP) Assays for the Rapid Detection of Toxigenic Aspergillus flavus and A. carbonarius in Nuts.

Aspergillus species create major postharvest problems due to the food losses caused by their mere presence and the hazardous mycotoxins they produce, such as aflatoxin B1 (AFB1) and ochratoxin A (OTA). These mycotoxins are mainly produced by A. flavus and A. carbonarius, respectively. In this study, we developed a rapid detection method for the two aforementioned species based on loop-mediated isothermal amplification (LAMP). The primers were designed to target genes belonging to the mycotoxin clusters pks and aflT for A. carbonarius and A. flavus, respectively. Result visualization was carried out in real time via the detection of fluorescent signals. The method developed showed high sensitivity and specificity, with detection limits of 0.3 and 0.03 pg/reaction of purified DNA of A. carbonarius and A. flavus, respectively. The assays were further implemented on inoculated nuts, including pistachios and almonds, after one-step crude DNA extraction. These tests revealed a detection level of 0.5 spore/g that shows the effectiveness of LAMP as a rapid method for detecting potentially toxigenic Aspergillus spp. directly in food. The validation of the assays included tests on a larger scale that further confirmed their sensitivity and specificity, as well as enabling the production of ready-to-use LAMP prototype kits. These kits are easy to use and aim to simplify the screening of food samples in order to monitor the presence of specific Aspergillus contaminations.

Obtaining Cellulose Fibers from Almond Shell by Combining Subcritical Water Extraction and Bleaching with Hydrogen Peroxide.

Almond shell (AS) represents about 33% of the almond fruit, being a cellulose-rich by-product. The use of greener methods for separating cellulose would contribute to better exploitation of this biomass. Subcritical water extraction (SWE) at 160 and 180 °C has been used as a previous treatment to purify cellulose of AS, followed by a bleaching step with hydrogen peroxide (8%) at pH 12. For comparison purposes, bleaching with sodium chlorite of the extraction residues was also studied. The highest extraction temperature promoted the removal of hemicellulose and the subsequent delignification during the bleaching step. After bleaching with hydrogen peroxide, the AS particles had a cellulose content of 71 and 78%, with crystallinity index of 50 and 62%, respectively, for those treated at 160 and 180 °C. The use of sodium chlorite as bleaching agent improved the cellulose purification and crystallinity index. Nevertheless, cellulose obtained by both bleaching treatments could be useful for different applications. Therefore, SWE represents a promising green technique to improve the bleaching sensitivity of lignocellulosic residues, such as AS, allowing for a great reduction in chemicals in the cellulose purification processes.

Enhancing Functional Properties and Protein Structure of Almond Protein Isolate Using High-Power Ultrasound Treatment.

The suitability of a given protein for use in food products depends heavily on characteristics such as foaming capacity, emulsifiability, and solubility, all of which are affected by the protein structure. Notably, protein structure, and thus characteristics related to food applications, can be altered by treatment with high-power ultrasound (HUS). Almonds are a promising source of high-quality vegetable protein for food products, but their physicochemical and functional properties remain largely unexplored, limiting their current applications in foods. Here, we tested the use of HUS on almond protein isolate (API) to determine the effects of this treatment on API functional properties. Aqueous almond protein suspensions were sonicated at varying power levels (200, 400, or 600 W) for two durations (15 or 30 min). The molecular structure, protein microstructure, solubility, and emulsifying and foaming properties of the resulting samples were then measured. The results showed that HUS treatment did not break API covalent bonds, but there were notable changes in the secondary protein structure composition, with the treated proteins showing a decrease in α-helices and ß-turns, and an increase in random coil structures as the result of protein unfolding. HUS treatment also increased the number of surface free sulfhydryl groups and decreased the intrinsic fluorescence intensity, indicating that the treatment also led to alterations in the tertiary protein structures. The particle size in aqueous suspensions was decreased in treated samples, indicating that HUS caused the dissociation of API aggregates. Finally, treated samples showed increased water solubility, emulsifying activity, emulsifying stability, foaming capacity, and foaming stability. This study demonstrated that HUS altered key physicochemical characteristics of API, improving critical functional properties including solubility and foaming and emulsifying capacities. This study also validated HUS as a safe and environmentally responsible tool for enhancing desirable functional characteristics of almond proteins, promoting their use in the food industry as a high-quality plant-based protein.

Formulation of a probiotic product using Almond gum.

BACKGROUND: The application of probiotics in food has expanded significantly, yet its viability remains a challenge. In response to this issue, this study explores a unique approach. Almond gum, a natural extract from Prunus dulcis, is utilized as the primary carrier matrix for a novel probiotic product featuring Saccharomyces boulardii, a probiotic yeast. METHODS: This study involves the entrapment of S. boulardii in almond gum through centrifugation (5 min at 1300 × g) and subsequent 24 h drying at 50 °C. Sensory evaluation and other investigations were conducted at different pH levels to assess viability and performance. RESULTS: Post-drying entrapment efficiency was 83.85%, underscoring the benefits of choosing almond gum as a carrier matrix. Promising results were observed from viability testing conducted in gastric juice (pH 1.2) and in simulated intestinal fluid (pH 6.8). Matrix stability was assessed by measuring cfu ml-1 following 7 days' storage at different temperatures, complemented by sensory analysis. CONCLUSION: Almond gum is a promising carrier matrix for probiotic products. Its high entrapment efficiency and its viability under challenging pH conditions demonstrate its efficacy. It is rich in carbohydrates and serves a dual purpose by acting as a prebiotic source, as confirmed through ultraviolet-visible (UV-visible) analysis. The study underscores the potential of this novel approach, providing insights into responses to viability challenges in probiotic food products. © 2024 Society of Chemical Industry.

Using predictive models unravel the potential of titanium oxide-loaded activated carbon for the removal of leachate ammoniacal nitrogen.

The TiO2 nanocomposite efficiency was determined under optimized conditions with activated carbon to remove ammoniacal nitrogen (NH3-N) from the leachate sample. In this work, the facile impregnation and pyrolysis synthesis method was employed to prepare the nanocomposite, and their formation was confirmed using the FESEM, FTIR, XRD, and Raman studies. In contrast, Raman phonon mode intensity ratio ID/IG increases from 2.094 to 2.311, indicating the increase of electronic conductivity and defects with the loading of TiO2 nanoparticles. The experimental optimal conditions for achieving maximum NH3-N removal of 75.8% were found to be a pH of 7, an adsorbent mass of 1.75 mg/L, and a temperature of 30 °C, with a corresponding time of 160 min. The experimental data were effectively fitted with several isotherms (Freundlich, Hill, Khan, Redlich-Peterson, Toth, and Koble-Corrigan). The notably elevated R2 value of 0.99 and a lower ARE % of 14.61 strongly support the assertion that the pseudo-second-order model compromises a superior depiction of the NH3-N reduction process. Furthermore, an effective central composite design (CCD) of response surface methodology (RSM) was employed, and the lower RMSE value, precisely 0.45, demonstrated minimal disparity between the experimentally determined NH3-N removal percentages and those predicted by the model. The subsequent utilization of the desirability function allowed us to attain actual variable experimental conditions.

Manufacturing plant-based non-dairy and probiotic frozen desserts and their impact on physicochemical, sensory and functional aspects.

The present study aimed to produce frozen dessert containing plant-based milk (almond, hazelnut, and lupine) and the probiotic Lb. acidophilus bacteria and to evaluate the chemical, microbiological and sensory properties during the 90 day-storage. Frozen dessert antioxidant capacity at day 0 and 90 of evaluation and changes in the phenolic compounds based on variations between different species were significant (p < 0.05). The differences in Lb. acidophilus counts between storage days were significant and values ranged from 4.15-8.99 log CFU/mL on the first day of storage to 3.61-7.06 at the end of the storage. Regarding the results of general acceptability in sensory evaluation, the highest color, taste and aroma scores was determined on day 0 in the hazelnut-lupine milk frozen dessert sample whereas the lowest was determined on day 30 in the almond-lupine milk frozen dessert sample. The samples with the highest antioxidant capacity were found on day 90 day in lupine frozen dessert (87.28 ± 0.007 mM) whereas the samples with the lowest antioxidant capacity were found on day 0 in the almond-hazelnut-lupine frozen dessert (18.83 ± 4.56 mM). Plant-based milk is considered suitable for the main ingredients in ice cream production, due to its health benefits its potential to be consumed as frozen dessert. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-024-05964-8.

Green recovery of phenolic compounds from almond hull waste using ultrasound-assisted extraction: phenolics characterization and antimicrobial investigation.

This research aims to maximize the extraction of phenolic compounds (PCs) from almond hull waste (AHW) using an ultrasound-assisted extraction (UAE) method, detect the PCs, and investigate the antimicrobial activity of the extracts against pathogens and interactions with a probiotic bacterium. The impact of various parameters including sonication amplitude, solvent/AHW ratio (mL/g), and extraction time on the total phenolic content (TPC) was investigated and the optimized extraction conditions were determined. The AHW extracts' minimum bacterial concentration (MBC) and minimum inhibitory concentration (MIC) against Staphylococcus aureus, Escherichia coli, and Lactobacillus plantarum were assessed. In optimal UAE conditions total PCs of 47.37 ± 0.24 mg gallic acid equivalent (GAE)/g dry weight (DW) were extracted. The HPLC analysis revealed that the flavonoid rutin, as well as p-coumaric acid and rosmarinic acid, were only seen in the extracts obtained by UAE. Furthermore, p-coumaric acid emerged as the most prevalent PC in the UAE extract. Antimicrobial activity analysis showed that UAE extracts exhibited higher effects in inhibiting the growth of E. coli, S. aureus, and L. plantarum. The use of UAE treatment resulted in the extraction of a diverse range of PCs with increased antioxidant capacity and antimicrobial activity. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-024-05969-3.

Protein hydrolysates prepared by Alcalase using ultrasound and microwave pretreated almond meal and their characterization.

The study aimed to optimize ultrasonic (US: 40 kHz/200 W for 10, 20, 30, 40, and 50 min), and microwave (MW: 160 W for 45, 90, 125, 180, and 225 s) pretreatment conditions on protein extraction yield and degree of protein hydrolysis (DH) from almond de-oiled meal, an industrial by-product. First order model was used to describe the kinetics of almond protein hydrolysates obtained with Alcalase. The highest DH, 10.95% was recorded for the US-50 min and 8.87% for MW-45 s; while it was 5.76% for the untreated/control sample. At these optimized pretreatment conditions, a 1.16- and 1.18-fold increment in protein recovery was observed for the US and MW pretreatments, respectively in comparison to the conventional alkaline extraction. The molecular weight distribution recorded for pretreated samples disclosed a significant reduction in the band thickness in comparison with control. Both the pretreatments resulted in a significant increase (P < 0.05) in the antioxidant activity, and TCA solubility index when compared with the control. Results evinced that US and/or MW pretreatments before enzymatic hydrolysis can be a promising approach for the valorization of almond meal for its subsequent use as an ingredient for functional foods/nutraceuticals which otherwise fetches low value as an animal feed.

Role of hydraulic traits in stomatal regulation of transpiration under different vapour pressure deficits across five Mediterranean tree crops.

The differential stomatal regulation of transpiration among plant species in response to water deficit is not fully understood, although several hydraulic traits have been reported to influence it. This knowledge gap is partly due to a lack of direct and concomitant experimental data on transpiration, stomatal conductance, and hydraulic traits. We measured sap flux density (Js), stomatal conductance (gs), and different hydraulic traits in five crop species. Our aim was to contribute to establishing the causal relationship between water consumption and its regulation using a hydraulic trait-based approach. The results showed that the species-specific regulation of Js by gs was overall coordinated with the functional hydraulic traits analysed. Particularly relevant was the negative and significant relationship found between the Huber value (Hv) and its functional analogue ratio between maximum Js and gs (Jsmax/gsmax) which can be understood as a compensation to maintain the hydraulic supply to the leaves. The Hv was also significantly related to the slope of the relationship between gs and Js response to vapour pressure deficit and explained most of its variability, adding up to evidence recognizing Hv as a major trait in plant water relations. Thus, a hydraulic basis for regulation of tree water use should be considered.

Almond intake during pregnancy in rats improved the cognitive performance of adult male offspring.

Background: Based on evidence there are accepted links among early nutrition, epigenetic processes, and cognitive performance. Almond as a nutritious food could exert neuroprotective effects and improve anxiety, learning, and memory.Methods: In the current study, female rats were fed with a diet containing 5% (w/w) almonds during the mating period (two days) and gestation period (21 consecutive days). Then, the effect of the almond diet on short-term memory (Y maze), anxiety (elevated plus maze), and stress adaptation (forced swimming test) were investigated in the adult male offspring. The hippocampus (HIP), prefrontal cortex (PFC), and amygdala (AMY) of offspring were collected, and the level of cyclic AMP response element-binding proteins (CREB), brain-derived neurotrophic factor (BDNF) was assessed by western blotting. Also, Monoamine oxidases (MAO)-A and B activity were evaluated via enzymatic assays.Results: Our results indicated that prenatal almond consumption improved memory, made a modest reduction in anxiety-like behavior, and increased stress adaptation in adult male offspring. Also, molecular assessments showed an increased level of CREB phosphorylation and BDNF in the HIP and PFC of the almond group, while the activity of MAO-A and MAO-B was inhibited by almond consumption in mentioned areas.Discussion: These findings introduce almonds as a beneficial diet during pregnancy, for improving short-term memory, stress adaptation, and cognitive performance in adult offspring.

Two Xylella fastidiosa subsp. multiplex Strains Isolated from Almond in Spain Differ in Plasmid Content and Virulence Traits.

The plant-pathogenic bacterium Xylella fastidiosa is a major threat to agriculture and the environment worldwide. Recent devastating outbreaks in Europe highlight the potential of this pathogen to cause emergent diseases. X. fastidiosa subsp. multiplex ESVL and IVIA5901 strains that belong to sequence type 6 were isolated from almond orchards within the outbreak area in Alicante province (Spain). Both strains share more than 99% of the chromosomal sequences (average nucleotide identity), but the ESVL strain harbors two plasmids (pXF64-Hb_ESVL and pUCLA-ESVL). Here, virulence phenotypes and genome content were compared between both strains, using three strains from the United States as a reference for the phenotypic analyses. Experiments in microfluidic chambers, used as a simulation of xylem vessels, showed that twitching motility was absent in the IVIA5901 strain, whereas the ESVL strain had reduced twitching motility. In general, both Spanish strains had less biofilm formation, less cell aggregation, and lower virulence in tobacco compared with U.S. reference strains. Genome analysis of the two plasmids from ESVL revealed 51 unique coding sequences that were absent in the chromosome of IVIA5901. Comparison of the chromosomes of both strains showed some unique coding sequences and single-nucleotide polymorphisms in each strain, with potential deleterious mutations. Genomic differences found in genes previously associated with adhesion and motility might explain the differences in the phenotypic traits studied. Although additional studies are necessary to infer the potential role of X. fastidiosa plasmids, our results indicate that the presence of plasmids should be considered in the study of the mechanisms of pathogenicity and adaptation in X. fastidiosa to new environments. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Evaluation of the fermentation potential of lactic acid bacteria isolated from herbs, fruits and vegetables as starter cultures in nut-based milk alternatives.

Fermentation of plant-based milk alternatives (PBMAs), including nut-based products, has the potential to generate new foods with improved sensorial properties. In this study, we screened 593 lactic acid bacteria (LAB) isolates from herbs, fruits and vegetables for their ability to acidify an almond-based milk alternative. The majority of the strongest acidifying plant-based isolates were identified as Lactococcus lactis, which were found to lower the pH of almond milk faster than dairy yoghurt cultures. Whole genome sequencing (WGS) of 18 plant-based Lc. lactis isolates revealed the presence of sucrose utilisation genes (sacR, sacA, sacB and sacK) in the strongly acidifying strains (n = 17), which were absent in one non-acidifying strain. To confirm the importance of Lc. lactis sucrose metabolism in efficient acidification of nut-based milk alternatives, we obtained spontaneous mutants defective in sucrose utilisation and confirmed their mutations by WGS. One mutant containing a sucrose-6-phosphate hydrolase gene (sacA) frameshift mutation was unable to efficiently acidify almond, cashew and macadamia nut milk alternatives. Plant-based Lc. lactis isolates were heterogeneous in their possession of the nisin gene operon near the sucrose gene cluster. The results of this work show that sucrose-utilising plant-based Lc. lactis have potential as starter cultures for nut-based milk alternatives.

Prunus Amygdalus Dulcis (Sweet Almond) Seed Meal.

The Expert Panel for Cosmetic Ingredient Safety reviewed updated information that has become available since their original assessment from 1983, along with updated information regarding product types, and frequency and concentrations of use, and reaffirmed their original conclusion that Prunus Amygdalus Dulcis (Sweet Almond) Seed Meal is safe for topical application to humans in the practices of use and concentration as described in this report.