Fruit Surface Research Articles

First Report of Diaporthe fusicola Causing Postharvest Fruit Rot of Peach (Prunus persica) in China.

In May 2022, rot symptoms were observed on postharvest peach (Prunus persica [L.] Batsch) fruits in a market in Nanchang, Jiangxi province (28°44' N; 115°50' E), China. A total of 80 samples were collected from three different fruit stalls through the market survey. The incidence of this disease was 10 to 15%, and severity varies from approximately 30 to 50% of fruit surface coverage. The symptom of infected fruits was circular, pale brown to brown, rotten, necrotic lesions, covered with white hyphae and small spore masses. Eight symptomatic peach fruits were surface disinfected with 75% ethanol for 30 sec and incisions were made with a sterile scalpel. Small pieces from symptomatic tissues were placed on a potato dextrose agar (PDA) medium and incubated at 25℃ for 7 days. Six isolates were obtained in total. Colonies on PDA were initially white, aerial, fluffy at first, and darkened with age. Alpha conidia were fusoid, hyaline, aseptate, guttulate, tapering towards ends, and ranged in size from 9.8 to 5.1 µm × 3.2 to 2.1 µm (x ̅=7.1 ± 1.0 × 2.6 ± 0.3 µm, n=60). Beta conidia were not seen. For further confirmation, genomic DNA was extracted from three isolates (04-10, 04-11, and 04-12), the internal transcribed spacer (ITS) region, beta-tubulin (TUB), calmodulin (CAL), partial translation elongation factor 1-alpha (TEF1-α) and histone H3 (HIS) genes were amplified by using primers ITS1/ITS4, Bt2a/Bt2b, CAL228F/CAL737R, EF1-728F/EF1-986R, CYLH3F/H3-1b (Udayanga et al. 2015), respectively. Sequences were deposited in GenBank (Accession Nos. ON994257 to ON994259 for ITS, OP076824 to OP076826 for TUB, OP076827 to OP076829 for CAL, OP076821 to OP076823 for TEF1-α, OP076830 to OP076832 for HIS). BLAST results showed that ITS and TEF1-α have 99.8% pairwise identity to Diaporthe fusicola (MN816432, KF576256), and the TUB, CAL, and HIS sequences also have 100% pairwise identity to D. fusicola (KF576287, MT978147, MT978142). Phylogenetic analyses of concatenated sequences using Bayesian inference and the maximum likelihood confirmed the identity. To verify Koch's postulates, the pathogenicity of three isolates was tested on harvested healthy peach fruits. Five surface-sterilized fruits were wounded by a sterile scalpel and inoculated with 5-mm-diameter mycelial plugs from 10-day-old PDA plates. Another set of five fruits was inoculated with sterilized PDA plugs as controls. All fruits were incubated at 26℃ with 80% relative humidity. The experiment was repeated three times. After 5 days, the fruit inoculated with mycelial plugs showed pale brown lesions with whitish mycelium mass, similar to the previous rot symptoms, whereas the control fruit remained symptomless. The same pathogen was reisolated from the inoculated fruit with symptoms and identified as D. fusicola by molecular techniques, but never from the control. Diaporthe fusicola (Diaporthe amygdali complex) was first described on leaves of Lithocarpus glabra in China (Gao et al. 2015) and reported as an agent causing leaf blotch on Osmanthus fragrans (Si et al. 2020) and pear shoot canker (Guo et al. 2020). However, this is the first report of D. fusicola causing postharvest fruit rot on peach. The managers involved must consider the impact of this disease and develop an effective fruit storage strategy.

Porosity quantification in pear fruit with X-ray CT and spatially resolved spectroscopy

Hypoxia-related disorders in apple and pears such as browning have been associated with insufficient transport of respiratory gasses inside the fruit during controlled atmosphere (CA) storage. Tissue porosity affects gas exchange and, hence, fruit respiration. It might, therefore, be interesting to adapt the storage conditions to the porosity of the fruit, especially in the case of low-porosity fruit like pears, which are highly susceptible to browning disorders. To improve the current CA storage strategies in that direction, fast, non-destructive measurement of fruit porosity is required. To this end, X-ray CT-based porosity maps and spatially resolved spectroscopy (SRS) were used to characterize respectively the porosity and optical properties of intact pear cultivars (Pyrus communis L.), including ‘Thimo’, ‘Cepuna’, and ‘Conference’. Thereafter, the link between the fruit porosity and light-scattering properties was investigated. The porosity of the tissue region from the fruit surface down to 3 mm deep as well as the spatially averaged porosity of intact pears from 3 cultivars were found to be linearly correlated to the reduced scattering coefficient (µs’) at 760 nm and 835 nm calculated from SRS measurements. Both ‘Cepuna’ and ‘Conference’ pears showed similar porosities and scattering levels, which were slightly higher than those observed for ‘Thimo’ pears. The presented results suggest the possible application of laser scatter imaging at 760 nm and 835 nm for fast, contactless and non-destructive assessment of pear porosity.

Mandarin orange (Citrus reticulata Blanco cv. Batu 55) ripeness level prediction using combination reflectance-fluorescence spectroscopy

Optical characteristics of Mandarin Orange cv. Batu 55 of different maturity level has been obtained using reflectance (Vis-NIR) and fluorescence spectroscopy. Spectra features of both reflectance and fluorescence spectroscopy have been evaluated to develop a ripeness prediction model. Spectra dataset and reference measurements were subject to the partial least square regression (PLSR) analysis. The best prediction models were using reflectance spectroscopy data showing the coefficient of determination R2 up to 0.89 and root mean square error (RMSE) of 2.71. On the other hand, it was found that fluorescence spectroscopy showed interesting spectra change in correlation with the accumulation of bluish and reddish fluorescence compounds in the lenticel spots on the fruit surface. The best prediction model using fluorescence spectroscopy data showed the R2 of 0.88 and RMSE of 2.81. Besides that, it wa found that combining spectra of reflectance and fluorescence features could increase the R2 of the partial least square regression (PLSR) model with Savitzky-Golay smoothing, up to 0.91 for brix-acid ratio prediction with RMSE 2.46. These results show the potential of the combined reflectance-fluorescence spectroscopy system for Mandarin ripeness assessment.

Effect of peach trichome removal on post-harvest brown rot and on the fruit surface microbiome

Postharvest peaches undergo rapid soft ripening and are susceptible to fungal diseases, which often result in severe losses during storage. The peach epidermis contains trichomes that form a specific structure on the peach surface. However, the relationship between trichomes and postharvest disease and involved mechanisms has not been well studied. In this study, the removal of trichomes reduced the disease incidence of peach brown rot caused by Monilinia fructicola. Cryo-scanning electron microscope observations showed that the fungal hyphae were found attached to the surface of trichomes. The fungal and bacterial communities on the peach surface at 0 d and 6 d were obtained by amplicon sequencing technology. Fungal communities on the peach surface contained a total of 1089 amplicon sequence variants (ASVs), which were demarcated into eight fungal phyla, 25 classes, 66 orders, 137 families, and 228 genera. The bacterial communities contained 10,821 ASVs assigned to 25 phyla, 50 classes, 114 orders, 220 families, and 507 genera. Higher bacterial diversity than fungal diversity was recorded on the peach epidermis. Trichome removal changed the microbial diversity and community on the peach surface. Compared with peach epidermis samples, the peach epidermis excluded trichomes samples contained similar fungal alpha diversity but significantly lower bacterial diversity. Seventeen different fungal genera and twenty-eight different bacterial genera were identified between peach trichome and peach epidermis excluded trichomes samples. The fungal and bacterial diversity on the peach epidermis showed a decreasing trend during storage. Beta diversity analysis revealed that the microbial communities of the peach epidermis and trichomes show different change trends between 0 d and 6 d. Trichome removal decreased relative abundance of Monilinia spp. and increased relative abundance of potential yeast and bacterial biocontrol agents. This study suggested that trichomes might modulate the microbial communities on fruit surfaces, and trichome removal technology after harvest might be developed to control peach postharvest decay.

Using Paclobutrazol and Leaf-to-fruit-ratio as Tools for Improving Yield and Quality of Non-dwarfing High-density Peach Orchards

Excessive fruit set and foliar shading are the major deterrents to the economic productivity of peach orchards raised on vigorous rootstocks. With the objective of obtaining an appropriate level of crop together with the best quality fruit from the high-density peach orchards, studies were conducted in the sub-Himalayan subtropics of Himachal Pradesh, India. In the Experimental orchard of the Department of Fruit Science, the premium Early Grande cultivar raised on non-dwarfing wild peach seedling rootstock was selected for the studies. The orchard soil was sandy loam soil with normal physico-chemical characteristics. The experiment was laid out in RBD factorial experimental design with paclobutrazol (PBZ) and leaf-to-fruit ratio (LFR) treatment factors; three levels of PBZ viz. P1-1500 ppm, P2-2500 ppm, P3-0 ppm and four levels of LFR i.e. L1-30:1, L2-40:1, L3-50:1 and L4 - normal leaf number were tried. The findings revealed that 2500 ppm PBZ together with 40:1 LFR treatment not only reduced the number of days from full bloom to maturity but also improved fruit thinning. The fruit retention was recorded better with 1500 ppm PBZ and 50:1 LFR; however, the yield was recorded highest with 2500 ppm PBZ and 40:1 LFR treatments. This treatment combination also resulted in better overall fruit quality in terms of fruit surface colour, total soluble solids, firmness, acidity, sugars etc. The control over vegetative growth was also observed better under this treatment combination.

Metabolic fingerprint of ‘WA 38’ green spot symptoms reveals increased production of epicuticular metabolites by parenchyma

Green spot is a pre-harvest physiological disorder of ‘WA 38’ apple fruit that can culminate in corking immediately underneath the peel surface. Unlike bitter pit and many other corking disorders, superficial symptoms emerge in the middle of the growing season as areas of peel discoloration, with the most severe symptoms appearing as parenchyma necrosis or corking that worsens until harvest. Our previous work demonstrated the mitigative effect of early season fruit bagging on green spot appearance, but the mechanism of its onset and the biochemical signatures associated with it remained unknown. We used metabolic profiling to, first, identify metabolites associated with green spot symptoms in the peel and cortex of ‘WA 38’ apples and, then, track changes before and after disorder onset until harvest from apples that were bagged, under a shade net, or uncovered (control). We linked metabolites from multiple metabolic pathways, including carotenoids, phenolics, triglycerides, and triterpenes, with peel and cortex green spot symptoms. Many pigment and triterpene compounds associated with cortex symptoms are typically far less abundant in cortex tissue than in peel. Light-altering treatments also impacted levels of several of these compounds during the growing season; however, the inability to predict which pre-symptomatic tissue would later develop symptoms compromised the establishment of disorder genesis and latent development using this technique. Despite these challenges, we linked novel metabolites and pathways with the disorder, including those that may indicate strengthening and isolation of symptomatic tissue, possibly to provide protections similar to the fruit surface.

Detection of early bruises on apples using hyperspectral reflectance imaging coupled with optimal wavelengths selection and improved watershed segmentation algorithm.

Bruises caused by mechanical collision during the harvesting and storage and transportation period are difficult to detect using traditional machine vision technologies because there is no obvious difference in appearance between bruised and sound tissues. As a result of its fast and non-destructive characteristics, hyperspectral imaging technology is a potential tool for non-destructive detection of fruit surface defects. In the present study, visible near infrared hyperspectral reflectance images of healthy apples and bruised apples at 6, 12 and 24 h were obtained. To reduce hyperspectral data dimension, optimal wavelength selection algorithms including principal component analysis (PCA) and band ratio methods were utilized to select the effective wavelengths and enhance the contrast between bruised and sound tissues. Then pseudo-color image transformation technology combining with improved watershed segmentation algorithm (IWSA) were employed to recognize the bruise spots. The result obtained showed that band ratio images obtained better detection performance than that of PCA. The G component derived from pseudo-color image of followed by IWSA obtained the best segmentation performance for bruise spots. Finally, a multispectral imaging system for the detection of bruised apple was developed to verify the effectiveness of the proposed two-band ratio algorithm, obtaining recognition rates of 93.3%, 92.2% and 92.5% for healthy, bruised and overall apples, respectively. The bruise detection algorithm proposed in the present study has potential to detect bruised apple in online practical applications and hyperspectral reflectance imaging offers a useful reference for the detection of surficial defects of fruit. © 2023 Society of Chemical Industry.

Analysis of mango fruit surface temperature using thermal imaging and deep learning

Abstract Thermal imaging has the potential to measure the object’s surface temperature. This study investigated the thermal behavior of mango fruit stored in a refrigerated environment. Thermal images of the fruit were collected with sufficient quality by supplying hot air to the acquisition environment. Grey-Level Co-occurrence Matrix (GLCM) features of mango images were determined to distinguish the subtle and noticeable changes. The thermal images were analyzed to find the temperature difference between the different regions of the fruit. The temperature of the bruise boundary (T bd ) was higher than the bruised center (T C ) throughout the storage period. In addition, an enhanced deep-learning model was used to predict the damaged mango. Over 10 days, 3500 thermal images were obtained from the 400 mangoes. In that, 80 % of the images were used for training, 10 % for testing, and 10 % for validation. The model achieved a classification accuracy of 99.6 %.

Stone fruit phenolic and triterpenoid compounds modulate gene expression of Monilinia spp. in culture media

Phenolic and triterpenoid compounds are essential components in stone fruit skin and flesh tissues. They are thought to possess general antimicrobial activity. However, regarding brown rot disease, investigations were only confined to a limited number of phenolics, especially chlorogenic acid. The activity of triterpenoids against Monilinia spp., as an essential part of the peach cuticular wax, has not been studied before. In this work, the anti-fungal effect of some phenolics, triterpenoids, and fruit surface compound (FSC) extracts of peach fruit at two developmental stages were investigated on Monilinia fructicola and Monilinia laxa characteristics during in vitro growth. A new procedure for assaying anti-fungal activity of triterpenoids, which are notoriously difficult to assess in vitro because of their hydrophobicity, has been developed. Measurements of colony diameter, sporulation, and germination of second-generation conidia were recorded. Furthermore, the expression of twelve genes of M. fructicola associated with germination and/or appressorium formation and virulence-related genes was studied relative to the presence of the compounds. The study revealed that certain phenolics and triterpenoids showed modest anti-fungal activity while dramatically modulating gene expression in mycelium of M. fructicola on culture medium. MfRGAE1 gene was overexpressed by chlorogenic and ferulic acids and MfCUT1 by betulinic acid, at 4- and 7- days of mycelium incubation. The stage II FSC extract, corresponding to the period when the fruit is resistant to Monilinia spp., considerably up-regulated the MfLAE1 gene. These findings effectively contribute to the knowledge of biochemical compounds effects on fungi on in vitro conditions.

Physicochemical and preservative properties of tyrosinase-crosslinked sodium caseinate-EGCG-carboxymethyl chitosan composite packaging: Comparison of blended and layer-by-layer films

Bio-based packaging materials reduce the interactions of foods with their environment, which improves their quality, safety, and shelf life. Simple blending and layer-by-layer (LBL) deposition methods are commonly used film preparation methods. However, it is not clear which method has a better preservation effect. In this study, differences in the structures and properties of tyrosinase-crosslinked sodium caseinate (SC)-epigallocatechin gallate (EGCG)-carboxymethyl chitosan (CMC) composite packaging materials (coatings and films) prepared by these two methods were compared. Fruit preservation experiments were carried out by applying blend or LBL coatings to banana or strawberry. The structural properties of films prepared by the blend and LBL methods were analyzed to provide insights into their different performances. The adsorption of the coating solution onto the fruit surfaces, as well as the microstructure and properties of the coatings formed, were the main factors affecting fruit preservation. Strawberry or banana coated by blend coatings exhibited a good appearance after 7 or 14 days. Overall, the water vapor barrier properties of the blend films were better than those of the LBL films. Moreover, the mechanical and EGCG-release properties of the blend films were also good. In summary, the properties of the coatings/films prepared by the blending and LBL methods were compared. This study helps to facilitate the rational design of edible packaging materials for different applications.

Effect of Irrigation with Treated Wastewater on Squash Yields, Soil Chemical and Microbial Properties

n this study, the effects of irrigation with treated wastewater (TWW) on soil chemical, microbiological, and yield of squash were investigated. Squash seedlings (Cucurbita pepo) were irrigated using conventional irrigation water (CIW), treated wastewater (TWW), and blended irrigation water (BIW). The drip irrigation system was used to irrigate Squash with CIW, TWW, and BIW. The concentration of all chemical and microbial irrigation water characteristics was falling within the limits of Jordanian standards (JS893/2021), except for turbidity and boron. Pathogens indicators such as Salmonella, and Helminth eggs were not found in TWW. TWW-irrigated plots had significant differences in electrical conductivity, organic carbon, total nitrogen, and sodium adsorption ratio (SAR). Total coliform and Escherichia coli (E. coli) contents increased significantly within TWW-irrigated plots. Squash’s fresh yield weight irrigated with TWW showed no significant difference compared with CIW. TWW and BIW treatments had a tendency toward lower fruit numbers than CIW. E. coli was not significantly different on the surface of squash fruits, while Total coliform increased significantly for fruits within the TWW-irrigated plots.

Overcoming lemon postharvest molds caused by Penicillium spp. multiresistant isolates by the application of potassium sorbate in aqueous and wax treatments.

Penicillium digitatum and Penicillium italicum are the main causal agents of postharvest diseases in lemon. Over the last decades, the appearance of isolates resistant to the main commercial fungicides has been considered one of the most serious problems for the citrus industry. In this work, potassium sorbate (KS) was evaluated as an alternative to chemical fungicides to control postharvest diseases caused by Penicillium isolates resistant to imazalil, thiabendazol, and pyrimethanil. In vitro assays showed that 1% KS inhibited conidia germination and mycelial growth of sensitive and resistant P. digitatum and P. italicum isolates, being this effect stronger at pH 5 than at pH 9. In curative treatments, the immersion of inoculated lemons in 1% KS aqueous solution for 30 s reduced green and blue molds incidences by around 80%. No wound protection effect was observed when wounded lemons were immersed in 3% salt solution before inoculation. Noteworthy, the inclusion of KS in a commercial wax coating effectively controlled green and blue molds, even in decays caused by fungicide resistance isolates. Together, results encourage the use of KS in lemon postharvest treatments to contribute to the management of resistant strains, which represent a major challenge in packinghouses worldwide. PRACTICAL APPLICATION: The use of KS in citrus postharvest treatments would help producers to reduce spoilage caused by Penicillium fungicide-resistant strains. The inclusion of this generally recognized as safe compound in wax coatings improves its persistence on the fruit surface, keeping product quality during long-term overseas transport. In sum, KS constitutes an affordable and eco-friendly option for controlling postharvest molds in lemon fruit.

Physicochemical properties of peach fruit assessed by non-destructive methodology related to the development of Monilinia fructicola during postharvest

ABSTRACT The concomitant evaluation of physicochemical properties and development of important diseases, such as brown rot in peaches postharvest, is hampered by the use of destructive methods for physicochemical analysis. Therefore, this study aimed to evaluate the physicochemical characteristics in wounded and unwounded ‘Chimarrita’ and ‘Maciel’ peaches inoculated with M. fructicola assessed by non-destructive methods. The fruits were stored at room temperature (25 ºC) for 10 days after harvest. Colorimeter, near-infrared spectroscopy and portable spectrophotometer DA-meter® (single index of absorbance difference, IAD index) were used to evaluate the physicochemical changes that naturally occurred in peaches during postharvest and due to pathogen development on the same fruit simultaneously. Incidence and severity of brown rot were evaluated by counting the number of lesions resulting from inoculation at 24, 48 and 60 h post inoculation. Also, the sporulation of M. fructicola on fruit surface was evaluated. The results indicated that differences between wounded and unwounded fruits related soluble solids content, pulp firmness, titratable acidity, dry matter and IAD did not affect the incidence of M. fructicola in both cultivars. However, the interaction between dry matter and colour at the time of inoculation influenced colonisation and consequent lesion size in inoculated wounded ‘Chimarrita’ fruits.

Automated detection of internal fruit rot in Hass avocado via deep learning-based semantic segmentation of X-ray images

Internal rot of avocado fruit (Persea americana), attributable to fungal infection, occurs at the end of the ripening process and causes only minor changes in the appearance and texture of the fruit surface. Manual inspection of rot by sight and touch commonly conducted in countries importing avocado fruit is time-consuming, labor-intensive, and subjective. In this context, X-ray line scanning has been proven as an advantageous method of fruit rot detection because of its speed of data acquisition and the indication of internal rot by bright regions in associated images. However, some fruit internal disorders exhibit only poor changes in contrast, resulting in low detectability by traditional image processing. This study aimed to test the effectiveness of a detection model using deep learning-based semantic segmentation in identifying two types of fruit rot, stem-end and body rot, in Hass avocados. Therefore, U-net+ + was trained and validated via 5-fold cross-validation to classify every pixel in an X-ray image as either infected or not. Then, each X-ray image was binarily classified based on either the presence or absence of internal fruit rots, achieving an accuracy of 0.98. Furthermore, the percentage of infected area was quantified with a root mean squared error (RMSE) of 3.15 %. Lastly, the proposed model detected both stem-end and body rot as well as rot along low-contrast fruit edges. The results of this study indicate that the proposed automatic inspection system using deep learning-based X-ray image analysis can effectively detect internal rot in Hass avocado fruit. This non-destructive, objective detection model can therefore increase efficiency and reduce misclassification in post-harvest avocado inspection. Furthermore, deep learning-based X-ray imaging has potential for applications in fruit inspection for internal cavities attributable to diseases or wounds.

Wafer-Level Highly Dense Metallic Nanopillar-Enabled High-Performance SERS Substrates for Molecular Detection.

Seeking sensitive, large-scale, and low-cost substrates is highly important for practical applications of surface-enhanced Raman scattering (SERS) technology. Noble metallic plasmonic nanostructures with dense hot spots are considered an effective construction to enable sensitive, uniform, and stable SERS performance and thus have attracted wide attention in recent years. In this work, we reported a simple fabrication method to achieve wafer-scale ultradense tilted and staggered plasmonic metallic nanopillars filled with numerous nanogaps (hot spots). By adjusting the etching time of the PMMA (polymethyl methacrylate) layer, the optimal SERS substrate with the densest metallic nanopillars was obtained, which possessed a detection limit down to 10-13 M by using crystal violet as the detected molecules and exhibited excellent reproducibility and long-term stability. Furthermore, the proposed fabrication approach was further used to prepare flexible substrates; for example, a SERS flexible substrate was proven to be an ideal platform for analyzing low-concentration pesticide residues on curved fruit surfaces with significantly enhanced sensitivity. This type of SERS substrate possesses potential in real-life applications as low-cost and high-performance sensors.

Apple Grading Based on Multi-Dimensional View Processing and Deep Learning.

This research proposes an apple quality grading approach based on multi-dimensional view information processing using YOLOv5s network as the framework to rapidly and accurately perform the apple quality grading task. The Retinex algorithm is employed initially to finish picture improvement. Then, the YOLOv5s model, which is improved by adding ODConv dynamic convolution and GSConv convolution and VoVGSCSP lightweight backbone, is used to simultaneously complete the detection of apple surface defects and the identification and screening of fruit stem information, retaining only the side information of the apple multi-view. After that, the YOLOv5s network model-based approach for assessing apple quality is then developed. The introduction of the Swin Transformer module to the Resnet18 backbone increases the grading accuracy and brings the judgment closer to the global optimal solution. In this study, datasets were made using a total of 1244 apple images, each containing 8 to 10 apples. Training sets and test sets were randomly created and divided into 3:1. The experimental results demonstrated that in the multi-dimensional view information processing, the recognition accuracy of the designed fruit stem and surface defect recognition model reached 96.56% after 150 iteration training, the loss function value decreased to 0.03, the model parameter was only 6.78 M, and the detection rate was 32 frames/s. After 150 iteration training, the average grading accuracy of the quality grading model reached 94.46%, the loss function value decreased to 0.05, and the model parameter was only 3.78 M. The test findings indicate that the proposed strategy has a good application prospect in the apple grading task.

TARGET OF EAT3 (TOE3) specifically regulates fruit spine initiation in cucumber (Cucumis sativus L.).

The presence or absence of spines is an important economic trait of cucumber fruit. Spines are believed to be a type of specialized trichome on the fruit surface and all the identified cucumber trichome-less mutants lack fruit spines. However, genes that specifically regulate fruit spine initiation remain to be identified. Here, we found that knocking out cucumber TARGET OF EAT3 homolog (CsTOE3), belonging to the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) family, affected flower development, and more interestingly, inhibited cucumber fruit spine initiation. On analyzing expression patterns by qRT-PCR and in situ hybridization assay, CsTOE3 was found to be highly expressed in male and female flowers, and its mRNA accumulated in the tips of sepal and petal primordia and in the cells of fruit spines and peels. Biochemical analyses indicated that CsTOE3 directly interacts with GLABRA1 (CsGL1) and TRANSPARENT TESTA GLABRA1 (CsTTG1), which are positive regulators of trichome formation. In addition, RNA-seq showed that the transcription levels of eight ERFs were significantly upregulated in CsTOE3 knockout lines. Phytohormone content analysis also revealed a significant increase in the amount of ethylene released by CsTOE3 knockout lines; treatment with the ethylene synthesis inhibitor aminoethoxyvinyl-glycine (AVG) partly restored the spineless phenotype. Our results suggest that CsTOE3 specifically regulates fruit spine initiation but does not affect the formation of trichomes on other organs in cucumber. Our findings may have a far-reaching significance for cucumber germplasm improvement and quality breeding using fruit spines as the target trait.

Subcellular damages of pathogenic fungi combined with gene expression analysis reveals mechanisms that cold plasma controlling apricot disease

Dielectric barrier discharge (DBD) plasma technology has proven effective in controlling postharvest fungus in fruits and vegetables. However, its mechanism of action is rarely reported. In this study, DBD technology was investigated to inhibit apricot diseases under the conditions of shelf simulation, and its mechanism was analysed. Apricot fruits and pathogenic fungal spores were treated with DBD of different voltage intensities（fruits: 80 kV, 90 kV, 100 kV; spores: 80 kV, 100 kV, 120 kV). Experimental data showed that DBD plasma treatment significantly reduced the microbial biomass on the surface of apricot fruit and inhibit Rhizopus oryzae and Alternaria tenuissima. Rhizopus oryzae and Alternaria tenuissima's spore germination decreased by 74.7% and 82.0%, respectively, after 40 s of processing with 100 kV DBD treatment. To investigate DBD plasma's antibacterial mechanism, deoxyribonucleic acid damage and the morphological characteristics of fungal spores were determined; this indicated that DBD plasma treatment resulted in nuclear degradation and cell deformation. In addition, DBD treatment enhanced apricots' expression of phenylalanine ammonia-lyase 1 (PAL1), aldehyde dehydrogenase 2B7 (ALDH2B7) and GDP-L-galactose phosphorylase (VTC2), delayed disease and improved quality under shelf storage conditions. The results demonstrated that DBD plasma treatment could control the primary diseases of apricot fruit and enhance the quality by destroying microbial spores and activating the disease-resistant genes of the fruit.

Impact of Novel Active Layer-by-Layer Edible Coating on the Qualitative and Biochemical Traits of Minimally Processed 'Annurca Rossa del Sud' Apple Fruit.

The color changes brought on by the enzymatic interactions of phenolic compounds with released endogenous polyphenol oxidase and the penetration of oxygen into the tissue has a significant impact on the commercialization of fresh-cut fruit, such as apples. This process causes a loss of quality in fresh-cut apples, resulting in browning of the fruit surface. By acting as a semipermeable barrier to gases and water vapor and thus lowering respiration, enzymatic browning, and water loss, edible coatings can provide a chance to increase the shelf life of fresh-cut produce. In this study, the effect of edible coatings composed of carboxymethylcellulose (CMC, 1%), sodium alginate (SA, 1%), citric acid (CA, 1%), and oxalic acid (OA, 0.5%) on fresh-cut 'Annurca Rossa del Sud' apple was studied. Four formulations of edible coatings, A. SA+CMC, B. SA+CMC+CA, C. SA+CMC+OA, and D. SA+CMC+CA+OA, were tested. Fresh-cut apples were dipped into different solutions and then stored at 4 °C, and physicochemical and biochemical analyses were performed at 0, 4, 8, and 12 days of storage. Results demonstrated that all four combinations improved the shelf-life of fresh-cut apple by slowing down the qualitative postharvest decay, total soluble solid, and titratable acidity. The browning index was highest in the control samples (82%), followed by CMC+SA (53%), CMC+SA+CA (32%), CMC+SA+OA (22%), and finally CMC+SA+CA+OA (7%) after 12 days of cold storage. Furthermore, coating application increased the bioactive compound content and antioxidant enzyme activities. Furthermore, the synergistic activity of SA+CMC+CA+OA reduces enzymatic browning, prolonging the postharvest life of minimally processed 'Annurca Rossa del Sud' apples.

AUTHENTICATION OF THREE WAX APPLES CULTIVARS (SYZYGIUM SAMARANGENSE (BLUME) MERR. & L.M. PERRY) BASED ON MORPHOLOGICAL CHARACTER AND FRUIT METABOLITE PROFILE

Wax apple is one of the superior fruits of Demak, especially cultivars 'Citra', 'Delima' and ‘Madu Deli Hijau'. Research on the wax apple of the three cultivars is still limited. Therefore, research on the authentication of wax apple cultivars based on morphological characters and metabolite profiles present in one location is important to do. The aims of this study were to identify morphological characters and analyze metabolite profiles, to analyze relationship and to identify morphological characters and metabolite marker profiles in the authentication activities of three wax apples cultivars. Sampling was in Boyolali Village, Demak Regency. The stages of this research included morphological characterization of stem, leaf, fruit and seed organs, phylogeny analysis with MVSP, metabolite profile analysis using GC-MS, and determination of morphological characters and metabolite profiles with PCA. The results showed that there were morphological diversity and metabolite profile variations of the three cultivars. Relationship analysis based on morphological characters and metabolite profiles resulted in different grouping patterns. 'Madu Deli Hijau' and 'Citra' are closely related based on morphological characters and a combination of morphological characters and metabolite profiles. Morphological characters in the authentication of the 'Citra' (dark red exocarp color), 'Delima' (bright red exocarp color, smooth and flat fruit surface, jagged fruit shape), in 'Madu Deli Hijau' (elongated leaf shape and exocarp is green with a pink tinge). Authentication of probable marker metabolite profiles on 'Citra', 'Delima' and 'Madu Deli Hijau' wax apples of 10, 7 and 5 compounds.