A new brown rot disease of plum caused by Mucor xinjiangensis sp. nov. and screening of its chemical control.

A novel species of Mucor was identified as the causal agent of a brown rot of Prunus domestica (European plum), widely grown in the south of Xinjiang, China. This disease first appears as red spots after the onset of the fruits. With favorable environmental conditions, fruit with infected spots turn brown, sag, expand, wrinkle, and harden, resulting in fruit falling. Fungal species were isolated from infected fruits. A phylogenetic analysis based on internal transcribed spacer (ITS) regions and the large subunit (LSU) of the nuclear ribosomal RNA (rRNA) gene regions strongly supported that these isolates made a distinct evolutionary lineage in Mucor (Mucoromycetes, Mucoraceae) that represents a new taxonomic species, herein named as Mucor xinjiangensis. Microscopic characters confirmed that these strains were morphologically distinct from known Mucor species. The pathogenicity of M. xinjiangensis was confirmed by attaching an agar disk containing mycelium on fruits and re-isolation of the pathogen from symptomatic tissues. Later, fourteen fungicides were selected to determine the inhibitory effect on the pathogen. Further, results showed that difenoconazole had the best effect on the pathogen and the strongest toxicity with the smallest half maximal effective concentration (EC50) value, followed by a compound fungicide composed of difenoconazole with azoxystrobin, mancozeb, prochloraz with iprodione, pyraclostrobin with tebuconazole, and trifloxystrobin with tebuconazole and ethhylicin. Present study provides the basis for the prevention and control of the novel plum disease and its pathogen.

Soluble sugar, organic acid and phenolic composition and flavor evaluation of plum fruits.

Plums (Prunus salicina and Prunus domestica) are prevalent in southwestern China, and have attracted interest owing to their delectable taste and exceptional nutritional properties. Therefore, this study aimed to investigate the nutritional and flavor properties of plum to improve its nutritional utilization. Specifically, we determined the soluble sugars, organic acids, and phenolic components in 86 accessions using high-performance liquid chromatography. Notably, glucose, fructose, malic, and quinic acids were the predominant sweetness and acidity in plums, with sucrose contributing more to the sweetness of the flesh than the peel. Moreover, The peel contains 5.5 fold more phenolics than flesh, epicatechin, gallic acid, and proanthocyanidins C1 and B2 were the primary sources of astringency. Correlation and principal component analyses showed eight core factors for plum flavor rating, and a specific rating criterion was established. Conclusively, these findings provide information on the integrated flavor evaluation criteria and for enhancing optimal breeding of plums.

Exploring the mechanism of nano-selenium treatment on the nutritional quality and resistance in plum plants.

The impact of emerging stressors, such as pesticides and heavy metals, on the nutritional quality, resistance, and antioxidant systems of crops is the subject of intense monitoring. Due to its low toxicity and biocompatibility, nano-selenium (nano-Se) increases antioxidant capacity more effectively than selenium (Se). However, the protective mechanism of nano-Se in plum trees is still unknown when subjected to long-term abiotic stress. In this study, nano-Se foliar application enhanced the fruit's fresh weight and diameter and plant growth and development by increasing the content of trace elements (Zn and Se) and amino acids (Try, Phe, Pro, and Arg) in leaves and fruits. Compared to the control, nano-Se treatment dramatically improved the plant's antioxidant system, resulting in a substantial increase in SOD (44.3 %), POD (24.3 %), and CAT (95.6 %) levels. It also increased IAA (118.8 %), total flavonoids (23.0 %), total phenols (15.8 %), rutin (37.7 %), quercetin (146.8 %), and caffeic acid (19.8 %) contents by regulating phenylpropane metabolic pathways. Targeted amino acid analysis indicated that nano-Se biofortification greatly enhanced the levels of His (60.7 %), Ser (123.5 %), Thr (105.7 %), Val (202.1 %), Ile (236.2 %), Leu (84.0 %), Tyr (235.0 %), and Phe (164.7 %). The non-target metabolomics results showed that nano-Se treatment stimulated plum growth and nutrition by boosting phenylpropane metabolism and amino acid production. Therefore, nano-Se can improve the quality and resistance of plums by regulating both the primary and secondary metabolic pathways of plants and enhancing the antioxidant capacity. This investigation provides a reference for extrapolating the positive effects of nano-Se on crop quality to other plant species.

Effects of probiotics fermentation on physicochemical properties of plum (Pruni domesticae semen) seed protein-based gel.

The plum seed protein isolates (PSPI) were used to prepare a gel by probiotics fermentation. The effects of fermentation time (from 0 to 12 h) on the physicochemical properties of PSPI gel were evaluated. The results showed that PSPI started to form a gel after 6 h of fermentation, as evidenced by a decrease in pH from 6.6 to 5.2, an increase in particle size from 10 µm to 40 µm, appearance of a new peak with retention time of 10 min in gel filtration high-performance liquid chromatography, and formation of aggregation and porous structure observed by fluorescence and scanning electron microscope. The PSPI gel from 9 h of fermentation exhibited the highest viscosity (318 Pa.s), storage modulus (18,000 Pa), water holding capacity (37 %), and gel strength (21.5 g) due to stronger molecular interactions such as hydrogen bond, electrostatic, hydrophobic interaction and disulfide bond. However, increasing fermentation time over 9 h led to disrupture of PSPI gel. Furthermore, the subunit around 15 kDa of PSPI disappeared after fermentation, indicating that the formation of PSPI gel was induced by both acidification and partial hydrolysis. Our results suggest that PSPI can provide an alternative for developing plant-based gel products.

Modeling and optimization of dyeing process of polyamide 6 and woolen fabrics with plum-tree leaves using artificial intelligence.

The dyeing process of textile materials is inherently intricate, influenced by a myriad of factors, including dye concentration, dyeing time, pH level, temperature, type of dye, fiber composition, mechanical agitation, salt concentration, mordants, fixatives, water quality, dyeing method, and pre-treatment processes. The intricacy of achieving optimal settings during dyeing poses a significant challenge. In response, this study introduces a novel algorithmic approach that integrates response surface methodology (RSM), artificial neural network (ANN), and genetic algorithm (GA) techniques for the precise fine-tuning of concentration, time, pH, and temperature. The primary focus is on quantifying color strength, represented as K/S, as the response variable in the dyeing process of polyamide 6 and woolen fabric, utilizing plum-tree leaves as a sustainable dye source. Results indicate that ANN (R2 ~ 1) performs much better than RSM (R2 > 0.92). The optimization results, employing ANN-GA integration, indicate that a concentration of 100 wt.%, time of 86.06 min, pH level of 8.28, and a temperature of 100 °C yield a K/S value of 10.21 for polyamide 6 fabric. Similarly, a concentration of 55.85 wt.%, time of 120 min, pH level of 5, and temperature of 100 °C yield a K/S value of 7.65 for woolen fabric. This proposed methodology not only paves the way for sustainable textile dyeing but also facilitates the optimization of diverse dyeing processes for textile materials.

De novo transcriptome profiling reveals the patterns of gene expression in plum fruits with bud mutations.

Bud mutation is a common technique for plant breeding and can provide a large number of breeding materials. Through traditional breeding methods, we obtained a plum plant with bud mutations (named "By") from an original plum variety (named "B"). The ripening period of "By" fruit was longer than that of "B" fruit, and its taste was better. In order to understand the characteristics of these plum varieties, we used transcriptome analysis and compared the gene expression patterns in fruits from the two cultivars. Subsequently, we identified the biological processes regulated by the differentially expressed genes (DEGs). Gene ontology (GO) analysis revealed that these DEGs were highly enriched for "single-organism cellular process" and "transferase activity". KEGG analysis demonstrated that the main pathways affected by the bud mutations were plant hormone signal transduction, starch and sucrose metabolism. The IAA, CKX, ARF, and SnRK2 genes were identified as the key regulators of plant hormone signal transduction. Meanwhile, TPP, the beta-glucosidase (EC3.2.1.21) gene, and UGT72E were identified as candidate DEGs affecting secondary metabolite synthesis. The transcriptome sequencing (RNA-seq) data were also validated using RT-qPCR experiments. The transcriptome analysis demonstrated that plant hormones play a significant role in extending the maturity period of plum fruit, with IAA, CKX, ARF, and SnRK2 serving as the key regulators of this process. Further, TPP, beta-glucosidase (EC3.2.1.21), and UGT72E appeared to mediate the synthesis of various soluble secondary metabolites, contributing to the aroma of plum fruits. The expression of BAG6 was upregulated in "B" as the fruit matured, but it was downregulated in "By". This indicated that "B" may have stronger resistance, especially fungal resistance. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-024-01472-3.

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Precipitation in the plum rain period accounts for 40%-50% of annual precipitation in the monsoon region. To clarify the temporal variability of the isotopic composition of precipitation during the plum rain period from event to interannual time scale and identify the influencing factors, we analyzed the isotopic composition of precipitation and its influencing factors in Nanjing from 2015 to 2022. By using the Hybrid Single-particle Lagran-gian Integrated Trajectory (HYSPLIT) model with specific humidity analysis, we investigated the water vapor source and influencing factors. The results showed that 1) the isotopic abundance of atmospheric precipitation was depleted in the summer and enriched in winter. dx was lower in summer and higher in winter. The isotopic abundance of precipitation from the plum rain was depleted compared to mean value of the whole-year. 2) There was no significant correlation between δ2H and δ18O of the plum rain (precipitation) with local meteorological factors. However, dx was lower in light rain, reflecting the effect of sub-cloud evaporation. The average dx was higher during plum rain period in years with more total plum rain precipitation. 3) The low-latitude South China Sea and the western Pacific Ocean source area provided water vapor for the plum rain. The shift of moisture source region led to abrupt changes in precipitation isotopes. Our results could provide data support for studies on precipitation isotopes in the monsoon region, as well as a reference point for further understanding the precipitation mechanism of the plum rain and stu-dying the seasonal variability of atmospheric circulation in the East Asian monsoon region.

Preliminary Investigation of Fruit Mash Inoculation with Pure Yeast Cultures: A Case of Volatile Profile of Industrial-Scale Plum Distillates.

This study investigates the effect of pure yeast culture fermentation versus spontaneous fermentation on the volatile compound profile of industrially produced plum brandy. Using traditional distillation methods, the evolution of key volatile compounds is monitored at seven different moments during the distillation process. By integrating advanced analytical techniques such as GC-MS and sensory evaluation, significant differences in the composition of the distillates are highlighted, particularly in terms of ethyl esters and higher alcohols which are key to the sensory properties of the final product. Distillates produced with the addition of pure cultures gave higher concentrations of esters than those obtained by wild fermentation. The results of our industrial research show that the most critical step is to limit the storage of the input raw material, thereby reducing the subsequent risk of producing higher concentrations of 1-propanol. Furthermore, our results indicate that the heart of the distillate can only be removed up to an ethanol content of approximately 450 g/L and that the removal of additional ethanol results in only a 10% increase in the total volume of the distillate, which in turn results in an increase in boiler heating costs of approximately 30%.

Profiling of Metabolites in Organically Grown Plums from Norway: Does Location or Cultivar Matter?

The aim of this work was to investigate the influence of two locations and seven cultivars on the profiling of metabolites in organically grown plums (Prunus domestica L.) fruit in Norway. P, K, and Ca were most abundant in the studied fruits, while Ba and Sr formed a clear line between the locations. The most abundant sugars were glucose, fructose, sucrose, and sorbitol, which together accounted for up to 97.00%. Quinic acid and malic acid were the predominant organic acids, while chlorogenic acid, rutin, and kaempferol-3-O-glucoside were the most abundant polyphenols. Plums from Ullensvang were characterized by a higher content of minerals, sugars, organic acids, total polyphenol content (TPC), and radical scavenging activity (RSA), while plums from Telemark had a higher content of quantified polyphenols. The cultivar 'Mallard' had the highest mineral and radical scavenging activity, 'Opal' had the sweetest fruit, 'Jubileum' had the highest acidity, 'Excalibur' had the highest TPC content, and 'Valor' stored the highest content of quantified polyphenols, especially chlorogenic acid. These results provide comprehensive information on the chemical profiles of selected plum cultivars, suggesting that organic plums are a rich source of beneficial compounds that can have a positive impact on human health.

Identification and Characterization of Colletotrichum Species Associated with Anthracnose Disease of Plum.

Plum (Prunus salicina Lindl.) is commercially cultivated worldwide for the high levels of nutrients in the fruit. In recent years, anthracnose has been severe in some plum planting areas in China, resulting in a large number of necrotic leaves, blight, and premature leaf fall. In this study, anthracnose samples of plum leaves were collected from Hezhou, Guilin, and Lipu in Guangxi Province and Meishan, Abe Tibetan, and Qiang Autonomous Prefecture of Sichuan Province. Characteristics of mycelia on potato dextrose agar, morphology of appressoria and conidia, and analysis of sequences of several marker regions (internal transcribed spacer [ITS] region, glyceraldehyde-3-phosphate dehydrogenase [GAPDH], chitin synthase [CHS-1], histone H3 [HIS3], actin [ACT], ß-tubulin [TUB2], and the intergenic region between apn2 and MAT1-2-1 [ApMat]). The resulting 101 Colletotrichum isolates obtained were identified as eight species: C. fructicola (50.5%), C. siamense (24.8%), C. karsti (8.9%), C. plurivorum (7.9%), C. aeschynomenes (3.9%), C. gloeosporioides (2%), C. celtidis (1%), and C. phyllanthi (1%). Representatives of all eight Colletotrichum species were found to cause disease on wounded leaves of plum seedlings in pathogenicity assays. As far as we are aware, this is the first report of anthracnose of plum caused by C. celtidis and C. phyllanthi in China.

The effects of plum products consumption on lipid profile in adults: A systematic review and dose-response meta-analysis.

Consumption of plum does not yet clearly affect the lipid profile. To ascertain the advantages of plum consumption on adult lipid profiles, we conducted a systematic review and meta-analysis. We used pertinent keywords to search the databases of PubMed, Scopus, and ISI Web of Science up to November 10th, 2022, in order to find trials that were eligible. According to the analyses, eating plum significantly lowers LDL levels compared to controls (WMD: -12.50 mg/dL, 95% CI: -22.06, -2.94, p = .010). Although plum consumption did not result in significant changes in TG (WMD: 0.56 mg/dL, 95% CI: -6.02, 7.15, p = .866), TC (WMD: -12.35 mg/dL, 95% CI: -25.05, 0.37, p = .057), and HDL concentrations (WMD: -0.39 mg/dL, 95% CI: -4.69, 3.89, p = .855) compared to the control group. Intake of plums, particularly the intervention type of dried plums, significantly decreased TC levels in unhealthy subjects, according to subgroup analysis. The consumption of plums had a notably statistically significant effect on LDL levels when the intervention type was dried plum and unhealthy subjects were enrolled. Due to the very low to moderate quality of meta-evidence, to show how eating plum improves lipid profile, further high-quality research are still essential.

Terminalia ferdinandiana Exell. extracts reduce pro-inflammatory cytokine and PGE2 secretion, decrease COX-2 expression and down-regulate cytosolic NF-κB levels.

Based on their high antioxidant capacity and noteworthy phytochemistry, Terminalia ferdinandiana fruit and leaves have attracted considerable recent interest for their therapeutic potential. Whilst those studies have reported a variety of therapeutic properties for the fruit, the anti-inflammatory potential of T. ferdinandiana has been largely neglected and the leaves have been almost completely ignored. This study investigated the immune-modulatory and anti-inflammatory properties of T. ferdinandiana fruit and leaf extracts by evaluating their inhibition of multiple pro- and anti-inflammatory cytokines and chemokines secretion in lipopolysaccharide (LPS)-stimulated and unstimulated RAW 264.7 macrophages using multiplex bead immunoassays and ELISA assays. The methanolic extracts were particularly good immune-modulators, significantly inhibiting the secretion of all the cytokines and chemokines tested. Indeed, the methanolic extracts completely inhibited IL-10, IFN-γ, IL-1ß, IL-6, MCP-1, and MIP-2a secretion, and almost completely inhibited the secretion of TNF-α. In addition, the methanolic T. ferdinandiana extracts also significantly inhibited cytosolic COX-2 levels (by 87-95%) and the synthesis of the PGE2 (by ~ 98%). In contrast, the methanolic extracts stimulated LTB4 secretion by ~ 60-90%, whilst the aqueous extracts significantly inhibited LTB4 secretion (by ~ 27% each). Exposure of RAW 264.7 cells to the methanolic T. ferdinandiana extracts also significantly down-regulated the cytosolic levels of NF-κB by 33-44%, indicating that the immune-modulatory and anti-inflammatory properties of the extracts may be regulated via a decrease in NF-κB transcription pathways. Taken together, these results demonstrate potent anti-inflammatory properties for the extracts and provide insights into their anti-inflammatory mechanisms.

An efficient cardio vascular disease prediction using multi-scale weighted feature fusion-based convolutional neural network with residual gated recurrent unit.

The cardiovascular disease (CVD) is the dangerous disease in the world. Most of the people around the world are affected by this dangerous CVD. In under-developed countries, the prediction of CVD remains the toughest job and it takes more time and cost. Diagnosing this illness is an intricate task that has to be performed precisely to save the life span of the human. In this research, an advanced deep model-based CVD prediction and risk analysis framework is proposed to minimize the death rate of humans all around the world. The data required for the prediction of CVD is collected from online data sources. Then, the input data is preprocessed using data cleaning, data scaling, and Nan and null value removal techniques. From the preprocessed data, three sets of features are extracted. The three sets of features include deep features, Principal Component Analysis (PCA), and Support Vector Machine (SVM)-based features. A Multi-scale Weighted Feature Fusion-based Deep Structure Network (MWFF-DSN) is developed to predict CVD. This structure is composed of a Multi-scale weighted Feature fusion-based Convolutional Neural Network (CNN) with a Residual Gated Recurrent Unit (GRU). The retrieved features are given as input to MWFF-DSN, and for optimizing weights, a Modernized Plum Tree Algorithm (MPTA) is developed. From the overall analysis, the developed model has attained an accuracy of 96% and it achieves a specificity of 95.95%. The developed model takes minimum time for the CVD and it gives highly accurate detection results.

Evaluation of improved functional characteristics of Lactobacillus enriched fruit bar prepared from stone fruits of Mid Himalayan belt.

Probiotic enriched functional fruit bar was prepared by using stone fruits (i.e. apricot and plum) of Mid Himalayan belt. Purpose of this study is to determine the survival of potential probiotic isolates in fruit bar and to study physico-chemical and sensorial properties of the product along with nutritional profile as well as microbial safety. Probiotics bacteria Lactobacillus rhamnosus KC6 and Lactobacillus paraplantarum Sam 1 were used to prepare fruit bar. Probiotic fruit bar was prepared in seven sets and was evaluated for various physico-chemical, nutritional and functional properties during storage period. It was revealed in the study that probiotic fruit bar is nutritionally and functionally better than non-probiotic fruit bar. Probiotic encapsulated bacteria in co-culture combinations efficiently enhanced nutritional quality of fruit bar. Microbiological evaluation of the product revealed that the viability of encapsulated probiotic co-culture bacteria was significantly greater as compared to free cells in the probiotic fruit bar.

Commodity risk assessment of plants of 12 selected Prunus species from Moldova.

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High-risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by defoliated 1- or 2-year old bare root plants for planting (grafted or not) of 12 Prunus species (Prunus armeniaca, P. avium, P. canescens, P. cerasifera, P. cerasus, P. davidiana, P. domestica, P. dulcis, P. fontanesiana, P. persica, P. salicina, P. tomentosa) imported from Moldova, taking into account the available scientific information, including the technical information provided by the applicant country. The evaluation identified three EU-quarantine pests, Erwinia amylovora (protected zone quarantine pest), Xiphinema rivesi non-EU populations and Xanthomonas arboricola pv. pruni (protected zone quarantine pest), which were selected for further evaluation, based on defined criteria, including their presence in the applicant country. It should be noted that there is uncertainty regarding whether all relevant pests have been identified due to a limited number of scientific publications and pest surveys in Moldova. For the three selected pests, the risk mitigation measures proposed in the technical dossier from Moldova were evaluated taking into account the possible limiting factors. For these pests, an expert judgement is given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on it, including uncertainties associated with the assessment. The degree of pest freedom varies among the pests evaluated, with Erwinia amylovora being the pest most frequently expected on the imported plants. The Expert Knowledge Elicitation indicated, with 95% certainty, that between 9823 and 10,000 bundles (comprising 10-20 plants per bundle) out of 10,000 bundles would be free from E. amylovora.

Selected Australian Terminalia Species Extracts Inhibit ß-Lactam Drug-Resistant Bacteria Growth and Potentiate the Activity of Conventional Antibiotics: Bioactivities and Phytochemistry.

Terminalia ferdinandiana Exell, Terminalia grandiflora Benth., Terminalia microcarpa Decne., and Terminalia muelleri Benth. (family: Combretaceae) belong to the genus Terminalia. Plants of this genus have been extensively used as traditional medicines to treat a variety of illnesses, including pathogen infections. However, we were unable to find any studies that have investigated the antibacterial activity of T. microcarpa. Similarly, whilst some preliminary studies have examined the antimicrobial properties of T. muelleri and T. grandiflora, they did not test the extracts against antibiotic-resistant pathogens. This study screens the antimicrobial activity of T. grandiflora, T. microcarpa, and T. muelleri and compares it to that of T. ferdinandiana extracts prepared from both the fruit and leaves against a range of pathogens, including multi-antibiotic-resistant strains. Solvents with varying polarities were used to extract different phytochemical constituents from the leaves of T. grandiflora, T. microcarpa, and T. muelleri and from the fruit and leaves of T. ferdinandiana. The aqueous and methanolic extracts each displayed significant antimicrobial activity when tested against the bacterial pathogens, including against the multidrug-resistant strains. When these extracts were tested in combination with selected antibiotics, some extracts potentiated the antimicrobial activity. This study identifies twelve synergistic, fifty-eight additive, and sixty non-interactive combinations, as well as thirty antagonistic effects. The extracts were evaluated for toxicity using the Artemia franciscana nauplii lethality assay (ALA) and were each classified as non-toxic, with the exception of the methanolic and aqueous T. ferdinandiana fruit extracts and the aqueous and ethyl acetate T. ferdinandiana leaf extracts. Metabolomic analysis using liquid chromatography-mass spectrometry (LC-MS) highlighted several flavonoids and tannins that may contribute to the antimicrobial activities reported herein. The potential antibacterial mechanism(s) of the T. ferdinandiana extracts are discussed in this study.

Revealing a Novel Potential Pest of Plum Trees in the Caucasus: A Species Resembling the European Leaf-Mining Stigmella plagicolella, Nepticulidae.

In instances of severe infestations, Nepticulidae larvae can inflict damage on cultivated plants. Previously, it was assumed that the Prunus-feeding Nepticulidae have continuous distribution from Europe to the neighboring Caucasus. During recent fieldwork in the Caucasus, leaf mines were found on plum trees that initially resembled those of Stigmella plagicolella (Stainton) in Europe. However, upon rearing the adults, significant differences emerged, leading to the hypothesis that a different Prunus-feeding species exists in the Caucasus; this challenges previous records in Western Asia. This paper presents the outcomes of our morphological, molecular, and statistical investigations, unveiling S. colchica sp. nov., a previously unknown potential plum-tree pest. Distinguished by male genitalia characteristics, the new species differs from S. plagicolella. The inter- and intraspecific divergences between S. colchica sp. nov. and S. plagicolella range from 3.5% to 6.02%. Moreover, the utilized delimitation algorithms reliably clustered two species separately, as does our mitotype network. A statistical analysis also shows a discernible trend between the leaf mines of S. colchica sp. nov. and S. plagicolella. This unexpected discovery not only documents a new potential pest, enhancing our understanding of the Caucasian fauna, but also contributes to the broader biological inventory.

First Report of Postharvest Fruit Rot Caused by Neofusicoccum parvum on Prunus salicina (Nai Plum) in China.

Nai plum (Prunus salicina var. cordata cv. Younai) is one of the most popular fruit crop in South China. In July 2023, a fruit rot of nai plum with about 5 % disease incidence was observed in a fruit market of Changsha city, Hunan Province, China. Initially, small, brown lesions appeared randomly on the fruit surface, with disease progression, the lesions gradually expanded and developed into soft rot. To isolate possible fungi from rotten fruits, small pieces (2 × 2 mm) from the periphery of 10 infected fruits were surface-sterilized using 70% ethanol for 10 s, rinsed three times in sterile distilled water, air dried, and then placed onto potato dextrose agar (PDA) plates and incubated at 28℃ for three days. Emerging colonies were subcultured by hyphal tip transfer on fresh PDA. A total of ten isolates with similar morphology were obtained. Fungal colonies were initially white, gradually turning gray and eventually becoming black, and aerial hyphae were dense and fluffy. Conidia were hyaline, single celled, ellipsoidal to fusiform, and range from 12.7 to 20.0 µm long (avg. 16.9 ± 2.39 µm) × 5.3 to 7.3 µm wide (avg. 6.3 ± 0.82 µm). These morphological characteristics of these isolates matched those of Neofusicoccum parvum (Phillips et al. 2013). To future confirmation of the identify, the internal transcribed spacer (ITS) region, translation elongation factor 1-alpha (TEF1-a), and beta-tubulin TUB2) genes of two representative isolates (JXNP1 and JXNP2) were amplified and sequenced using primer sets ITS5/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999; Phillips et al. 2013), and BT2A/BT2B (Glass and Donaldson 1995), respectively. The sequences of both isolates were deposited in GenBank for the ITS (accession nos. OR899331 and OR899332), TEF1-a gene (accession nos. OR909890 and OR909891) and TUB2 gene (accession nos. OR909892 and OR909893). BLAST analysis showed 99-100% identity with the ex-type strain of N. parvum (CMW9081) for ITS, TEF1-a and TUB2. A maximum likelihood phylogenetic tree was constructed using IQtree web server based on combined ITS, TEF1-a and TUB2 data set. The phylogenetic tree revealed that two isolates clustered with N. parvum in a clade with 90% bootstrap support. Based on morphological and molecular data analysis, the isolates were identified as N. parvum. To confirm the pathogenicity, five healthy nai plum fruits were wounded by using a sterile needle after surface sterilization with 75% ethanol, then a 5-mm-diameter mycelial disc of isolate JXNP1 was taped to the wound, the control fruits were taped with sterile agar plugs. All fruits were incubated at 25 ℃ with 80% humidity. After five days, typical naturally occurring fruit rot symptoms appeared on the fruits which inoculated with N. parvum, whereas control fruits remained asymptomatic. To fulfill Koch's postulates, the pathogen was re-isolated from the inoculated fruits and comfirmed as N. parvum by morphological and molecular analysis. Previous studies reported that N. parvum caused fruit rot on various common fruits in China, including loquat, kiwifruit and citrus (Lei et al. 2013; Zhai et al. 2019; Zhou et al. 2013). To our knowledge, this is the first report of N. parvum causing postharvest fruit rot on nai plum in China. This finding provides critical insights for the management of the high-risk disease on plum in China.

Effect of exogenous melatonin on antioxidant properties and fruit softening of 'Fengtang' plum fruit (Prunus salicina Lindl.) during storage at room temperature.

'Fengtang' plums soften quickly and lose flavor after harvest. This study comprehensively evaluated the effect of exogenous melatonin on the fruit quality of 'Fengtang' plums. According to our findings, exogenous melatonin prevented plum fruit from losing water, delayed the decline in firmness, and preserved a high TSS/TA level. Additionally, exogenous melatonin also enhanced the activity of antioxidant enzymes and increased the non-enzymatic antioxidants, thereby further increasing the antioxidant capacity of plum fruit. Notably, exogenous melatonin delayed the degradation of covalent soluble pectin (CSP), cellulose, and hemicellulose, as well as the rise in water-soluble pectin (WSP) concentration and the activity of cell wall degrading enzymes. Further investigation using atomic force microscopy (AFM) revealed that the chain-like structure of ionic-soluble pectin (ISP) and the self-assembly network structures of CSP were depolymerized, and melatonin treatment retarded the depolymerization of pectin structures. Our results showed that exogenous melatonin preserved the postharvest quality of plum fruits by controlling fruit softness and antioxidant capacity during storage.

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.