Pear Research Articles

Transcription factor PbrERF114 is involved in the regulation of ethylene synthesis during pear fruit ripening.

The plant hormone ethylene is indispensable to the ripening of climacteric fruits. Although extensive studies have been conducted on ethylene signaling, the ethylene response factor (ERF)-mediated transcriptional regulation of ethylene biosynthesis in pear fruits remains to be fully elucidated. We here constructed, sequenced, and analyzed transcriptome libraries in ethephon-treated and 1-MCP-treated Cuiguan pear fruits. In total, 721 fruit ripening-associated differentially expressed genes were identified. Among them, two key genes exhibited positive correlations: the 1-aminocyclopropane-1-carboxylic acid synthase (ACS)-encoding gene PbrACS3 and the ERF-encoding gene named PbrERF114. PbrERF114 overexpression increased ethylene production as well as the PbrACS3 expression level. Conversely, virus-induced gene silencing downregulated PbrERF114, thereby decreasing ethylene production and reducing PbrACS3 expression levels. Notably, PbrERF114 could directly interact with PbrACS3 and PbrERF24 promoters, thus inducing their expression. However, it did not result in an enhancement in luciferase activity, which is regulated by the PbrACS1b or PbrACO1 promoter. PbrERF24 could directly bind to PbrACO1 as well as PbrACS3 to promote ethylene synthesis. In conclusion, PbrERF114 can directly and indirectly mediate ethylene biosynthesis by transcriptionally regulating PbrACS3 and PbrERF24, respectively, thereby triggering a signaling cascade that induces the expression of both PbrACS3 and PbrACO1.

The Prickly Pear, a shrub of real contribution to the livelihoods of farmers in in eastern dray land of Algeria

The study aims to assess the economic benefits and poverty impact of prickly pear fruit sales, focusing on commercial practices and the socio-economic status of participants. Data was gathered from 60 individuals across 32 locations through face-to-face surveys conducted from June to September 2023. The analysis, covering 20% of the regional actors, revealed that most participants were relatively young, with higher primary education levels and low university education (8.33%). Women involved were mostly divorced, and the majority of sellers were private farm owners, with others being forwarders and traders. Unemployment drove their engagement in this activity. The average income from prickly pear sales is 89.103 DZD, with net earnings of 60,000.00 DZD per trader, which increases with hours worked. Approximately 60 traders generate a total seasonal income of around 42,000.00 DZD, significantly benefiting local economies. Prickly pear trading offers crucial support to households, particularly during tough economic times, showcases its importance despite modest returns. The prickly pear trade in the region plays a vital role in supporting local households economically, especially during periods of financial instability. The trade offers both a source of income and an opportunity for independence, despite challenges associated with harvesting and market dynamics. The study concludes that prickly pear sales provide a sustainable income source with potential for growth, suggesting broader use of these crops for food, fodder, and energy in Algeria.

Characterization of autochthone biological control agents for pear protection against the brown spot of pear disease caused by Stemphylium vesicarium

AbstractStemphylium vesicarium is an important phytopathogen for many plant species, that switches between necrotrophic and saprophytic lifestyles. In the last decade, it has severely affected pear production worldwide, causing the so-called brown spot of pears (BSP), which led to the replacement of several pear orchards in northern Italy with consequent important economic losses. In the field, the management of the disease still relies on fungicide application, though several resistant genotypes of the pathogen emerged through the years. In the present study, three different bacterial species have been isolated from an infected orchard and evaluated as potential biological control agents (BCAs) against a local isolate of Stemphylium vesicarium. Two bacterial isolates belonging to the Bacillus genus demonstrated a significant ability to inhibit S. vesicarium growth in vitro, both through direct antagonism and the emission of volatile organic compounds (VOCs). The cell-free supernatant from one of these isolates exhibited a strong biocontrol activity, particularly through compounds extracted in acidic conditions. The protective effectiveness of the two most promising BCAs was further validated on detached pear fruits infected with S. vesicarium. Overall, the findings suggest that these two BCAs have the potential to be developed into a bio-based alternative to fungicides to control BSP, thus contributing to a more sustainable pear production.

AaSlt2 Is Required for Vegetative Growth, Stress Adaption, Infection Structure Formation, and Virulence in Alternaria alternata

Slt2 is an important component of the Slt2-MAPK pathway and plays critical regulatory roles in growth, cell wall integrity, melanin biosynthesis, and pathogenicity of plant fungi. AaSlt2, an ortholog of the Saccharomyces cerevisiae Slt2 gene, was identified from A. alternata in this study, and its function was clarified by knockout of the gene. The ΔAaSlt2 strain of A. alternata was found to be defective in spore morphology, vegetative growth, and sporulation. Analysis of gene expression showed that expression of the AaSlt2 gene was significantly up-regulated during infection structure formation of A. alternata on hydrophobic and pear wax extract-coated surfaces. Further tests on onion epidermis confirmed that spore germination was reduced in the ΔAaSlt2 strain, together with decreased formation of appressorium and infection hyphae. Moreover, the ΔAaSlt2 strain was sensitive to cell wall inhibitors, and showed significantly reduced virulence on pear fruit. Furthermore, cell wall degradation enzyme (CWDE) activities, melanin accumulation, and toxin biosynthesis were significantly lower in the ΔAaSlt2 strain. Overall, the findings demonstrate the critical involvement of AaSlt2 in growth regulation, stress adaptation, infection structure formation, and virulence in A. alternata.

Ensiling as a Conservation Technique for Opuntia ficus indica (L.) By-Products: Peel and Pastazzo

Italy is the third largest producer of Opuntia fruits in the world after Mexico and the United States, and 97.72% of these fruits produced by Italy are grown in Sicily. The use of prickly pear fruits or juice leads to a high production of by-products. In this study, ensiling was chosen to preserve prickly pear peels (PPPs) and “pastazzo” (PPS) mixed with 12% wheat bran. PPP silage presented a lower DM than PPS silage (20.03 vs. 41.37%; p < 0.01), as well as aNDFom (25.31 vs. 66.66% DM; p < 0.01), but had the best protein content (12.02 vs. 9.55% DM; p < 0.01). For both by-products, fermentation proceeded rapidly with increasing temperature, with the temperature for PPS (38 °C) being higher than that for the PPP (30 °C). Mesophilic LAB (lactic acid bacteria) were detected at higher levels than thermophilic LAB, and rod counts were higher than cocci counts. The detected organic acids and silage pH indicate an optimal fermentation process for these by-products. PPP silage had a higher polyphenol content than PPS silage (30.24 vs. 24.22 mg GAE/g DM; p < 0.01) and, consequently, also higher antioxidant activity. The results of this study on the mineral composition and macro- and micro-nutrients in silage highlight that these by-products are sources of minerals, with high levels of potassium, calcium, and magnesium.

Effects of Thifluzamide Treatment on the Production of Cell Wall Degrading Enzymes in Rhizoctonia solani and Phenylpropane Metabolism in Pear Fruit

The study aimed to investigate the effects of thifluzamide (2.67 mg/L) on ‘Huangguan’ pear fruit rot caused by Rhizoctonia solani during storage, as well as the activities of polygalacturonase (PG), pectin methylesterase (PME), polygalacturonic acid trans-eliminase (PGTE), pectin methyl trans-eliminase (PMTE), xylanase, and pectate lyase (PL) secreted by R. solani. The results showed that thifluzamide treatment significantly inhibited the activities of PG, PME, PGTE, PMTE, xylanase, and PL secreted by R. solani after 3 days in vitro culture, compared to the control. Thifluzamide also increased the activities of phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), and 4-coumarate CoA ligase (4CL), and the contents of flavonoids and total phenolic compounds in pear fruit. Furthermore, thifluzamide increased the expression of PcPAL, PcC4H, Pc4CL, Pcβ-1,3-GA, PcLCH, PcF3H, and PcDFR involved in phenylpropanoid metabolism in pear fruit. In conclusion, thifluzamide treatment reduced the infection ability of R. solani by inhibiting the expression of the genes encoding cell wall-degrading enzymes in R. solani. At the same time, it inhibited the activities of cell wall-degrading enzymes induced resistance against R. solani infection in ‘Huangguan’ pears by promoting phenylpropane metabolism.

Pan-transcriptome analysis provide insights into resistance and fruit quality breeding of pear (Pyrus pyrifolia)

Pyrus pyrifolia, commonly known as sand pear, is a key economic fruit tree in temperate regions and possesses highly diverse germplasm resources for pear quality improvement. However, research on the relationship between resistance and fruit quality traits during the breeding of fruit species like pear is limited. Pan-transcriptomes effectively capture genetic information from coding regions and reflect variations in gene expression between individuals. Here, we constructed a pan-transcriptome composed of 506 samples from different tissues of sand pear, and explored the intrinsic relationships among phenotypes and the selection for disease resistance during improvement based on expression presence/absence variation (ePAVs). The pan-transcriptome contains 156,744 transcripts, among which the novel transcripts show significant enrichment in the defense response. Interestingly, disease resistance genes are highly expressed in landraces of pear but have been selected against during the improvement of this perennial tree species. We found that genetically diverse landraces can be divided into two subgroups and inferred that they have undergone different dispersal processes. Through co-expression network analysis, we confirmed that the formation of stone cells in pears, the deposition of fruit anthocyanins, and the ability to resist stress are interrelated. They are jointly regulated by several modules, and the expression of regulatory genes has a significant correlation. Moreover, we identified candidate genes such as HKL1 that may affect sugar content and are missing from the reference genome. Our study provides insights into the associations between complex fruit traits, while providing a database resource for pear disease resistance and fruit quality breeding.

Ppbbx24-del mutant positively regulates light-induced anthocyanin accumulation in the ‘Red Zaosu’ pear (Pyrus pyrifolia White Pear Group)

Red fruit peel is one of the most valuable economic traits in pear and is mainly determined by anthocyanins. Many pear cultivars with a red peel originated from bud sports; however, little is known about the genetic mechanisms underlying this trait. We have previously identified a mutant PpBBX24 containing a 14-nucleotide deletion in the coding region (Ppbbx24-del) as the only known variant associated with the red coloration of the mutant ‘Red Zaosu’ pear (Pyrus pyrifolia White Pear Group). Herein, we analyzed the role of the mutant gene in red coloration and its mechanism of action. The results showed that light promoted red <pg=>peel coloration in ‘Red Zaosu’ pear, and Ppbbx24-del had positive effects on light-induced anthocyanin biosynthesis, while normal PpBBX24 had the opposite effects. Transient and stable <pg=>transformation experiments confirmed that Ppbbx24-del could promote anthocyanin accumulation in pear fruit peels, calli, and tobacco flowers. Due to the loss of NLS and VP domains, Ppbbx24-del co-localized in the nucleus and cytoplasm, whereas PpBBX24 localized only in the nucleus. Real-time PCR and transcriptome analyses indicated that PpMYB10 and PpHY5 is highly expressed in ‘Red Zaosu’ pear. In yeast one-hybrid and dual luciferase assays, Ppbbx24-del and PpHY5 independently promoted the expression of PpCHS, PpCHI, and PpMYB10 by binding to their promoters; however, PpBBX24 did not affect the expression of these genes. Additionally, we found that Ppbbx24-del and PpHY5 had additive effects on the expression of PpCHS, PpCHI, and PpMYB10, as they promote the expression of anthocyanin synthesis genes separately. The co-expression of PpBBX24 and PpHY5 inhibited the activation of downstream genes by PpHY5, and this was attributed to the interaction between the two loci. In conclusion, our results clarify the molecular mechanism by which mutant Ppbbx24-del and PpBBX24 exert opposite effects in the regulation of anthocyanin accumulation in pear. These findings lay an important theoretical foundation for the use of Ppbbx24-del to create red pear cultivars.

PbRVE6 Promotes Anthocyanins Accumulation in Pear Fruit Peel by Regulating Key Biosynthetic Genes.

Red peel color, a desirable trait in pears, is determined by anthocyanin accumulation. While REVEILLE (RVEs) transcription factors regulate anthocyanin biosynthesis in some plant species, their role in pear peel has not been well-studied. This study investigates the function of RVEs in anthocyanin biosynthesis in 'Zaosu' (low anthocyanin content) and its red bud mutant, 'Red Zaosu' (high anthocyanin content) fruit peel. Consistent with higher anthocyanin content, 'Red Zaosu' pears exhibited increased PbRVE6 expression compared to 'Zaosu', while PbRVE3a and PbRVE3b levels remained unchanged. Additionally, PbRVE6 was localized to the nucleus. Overexpression of PbRVE6 in 'Zaosu' pear pericarp significantly increased anthocyanin content and upregulated key anthocyanin pathway genes PbANS and PbUFGT. Conversely, VIGS silencing of PbRVE6 in 'Red Palacer' pears led to decreased expression of PbANS and PbUFGT and a slight reduction in anthocyanin content. Yeast one-hybrid and dual-luciferase assays confirmed that PbRVE6 can bind and activate the promoters of PbANS and PbUFGT. These findings demonstrate that PbRVE6 promotes anthocyanin accumulation in pear peel by directly regulating PbANS and PbUFGT expression. This study provides a valuable foundation for understanding the regulatory network of anthocyanins in pear peels, and offers potential genetic resources for the production of new pear germplasm.

Wild pear (Pyrus pyraster (L.) Burgsd.) fruit and seed morphology depending on fruit size

The current study aims to evaluate the effects of fruit size of wild pear (Pyrus pyraster (L.) Burgsd.) on morphological fruit and seed traits. Wild pear fruit was collected from 10 trees in the area of Žumberačko gorje in the fall of 2022. The fruit was randomly collected from the ground and divided into three groups according to their weight (small (&lt;10 g), medium (10 – 15 g) and large (&gt;15 g)). Fruit size had a significant effect on the following morphological traits: fruit weight, fruit length, fruit width, the number of filled seeds, the weight of fresh seeds per fruit, the weight of 1 fresh seed and the weight of air-died seed, while no significant difference was found for fruit shape index, the number of empty seeds, the weight of 1 air dried seed and the share of seed dry matter. For all the aforementioned traits where the difference was significant, large fruit had significantly highest values, while in most cases (with the exception of the weight of 1 fresh seed), medium fruit had significantly higher values than small fruit. Comparing the correlation coefficients between different fruit size groups, it is evident that higher fruit size traits had a significant effect on the number of filled seeds in medium and large wild pear fruit only. In addition, it is visible that fruit weight and width, and not fruit length, had of the largest impact on the number of filled seeds. The principal component analysis revealed 3 significant principal components with eigenvalues greater than 1, which explained 75.88% of the total variability. It was shown that large fruit distinguish themselves from small and partly between medium by F1 axis. F1 was mainly influenced by fruit weight, fruit length, fruit width, the number of filled seeds, the weight of fresh seeds per fruit and the weight of air-dried seed per fruit. Based on the results obtained from this study, it can be concluded that for nursery production of wild pear seedlings bigger fruit should be used due to the higher number of filled seeds.

Isolation and Identification of Pear Ring Rot Fungus and Resistance Evaluation of Different Pear Varieties

Botryosphaeria dothidea is a significant plant pathogen responsible for causing ulcers, wilt, and fruit decay across a wide range of host plants. One notable fungal disease attributed to B. dothidea is pear tree ring rot, which currently ranks among the most severe diseases affecting pear trees in China. This pathogen primarily targets branches and fruits, occasionally impacting leaves as well, leading to tree weakening, fruit rot, and leaf drop. The annual repercussions of this disease severely affect both the yield and quality of pear fruits, thereby impeding the healthy development of the pear industry. Recent studies have indicated that other species within the B. dothidea complex can also induce pear ring rot; however, specific physiological strains of B. dothidea remain unreported. Consequently, this study collected tissues from pear trees infected with ring rot from orchards located in Liaoning, Hebei, Shandong, and other regions throughout China. Through morphological characterization combined with pathogenicity assessments and DNA sequence comparisons involving partial internal transcribed spacer (ITS), translation elongation factor (TEF), and β-tubulin (TUB) genes, 21 strains belonging to the Botryosphaeria spp. were identified. These 21 strains served as research subjects for inoculating dormant annual branches from 30 germplasm resources of pear trees in vitro. The results demonstrated that all tested strains could induce lesions on the branches which were characterized by dark brown spots. Furthermore, inoculation experiments involving these 21 strains were conducted to evaluate the resistance levels of various pear varieties against ring rot disease. The resistance was assessed by inoculating different isolates onto distinct pear varieties; this approach established the criteria for evaluating resistance while minimizing identification errors stemming from the variable responses exhibited by certain varieties towards individual strains. Ultimately, this study aims to provide a theoretical foundation for effective prevention and treatment strategies against pear ring rot.

Fruit growth and water use of two pear cultivars grown in South Africa: implications for precision irrigation scheduling

In South Africa, as in other semi-arid countries, sustainable production of high-value crops requires precise management of limited water resources. We investigated daily and seasonal changes in stem and fruit growth as indicators of water stress in pear (Pyrus communis L.) trees, in the Western Cape Province. Stem and fruit growth data were collected hourly throughout the 2022–2023 growing season on 2 cultivars commonly planted in South Africa – Packham’s Triumph and Forelle. Soil water content, tree sap flow, and orchard microclimate were also monitored. Fruit maximum daily shrinkage (MDS) was highly sensitive to soil water deficit and more sensitive than stem size changes. However, the patterns of fruit MDS for both cultivars changed as the season progressed. Early in the season (October–December), there was a strong correlation between fruit MDS and soil water deficit (R2 ~ 0.72). The fruit shrunk with increasing soil water deficit as water loss through transpiration exceeded gains through xylem and phloem inflows. In contrast, daytime fruit size swelled from late December until harvest (February/March), likely because of the dominance of phloem inflows and decreased peel transpiration as the fruit matured. Correlation between fruit expansion and soil water deficit was weaker (R2 ~ 0.32) during the later stage even though fruit growth continued until harvest. Stem MDS consistently showed midday shrinkage throughout the season in response to soil water deficit, but with more scatter (R2~ 0.37). Seasonal total transpiration was greater for Forelle (733 mm) than Packham’s Triumph (539 mm) because of the higher leaf area index of the Forelle and the longer growing season. This study suggests that pear fruit growth data can provide accurate estimates of tree water status, but only during the early stages of growth. Towards maturity, fruit size changes respond indirectly to water deficit, possibly through reductions in photosynthesis.

A New Source of Inoculum for Stemphylium vesicarium: Consequences for the Management of Brown Spot of Pear

Brown spot of pear (BSP), caused by Stemphylium vesicarium, is one of the most dangerous pear fungal diseases, being responsible for huge losses in production. Currently, in order to increase its containment, chemical control is implemented in conjunction with agronomic techniques able to reduce BSP inoculum sources (e.g., orchard grass sanitation, litter removal or application of biocontrol agents). Regardless, despite the introduction of agronomic practices, the complete control of the disease is still rarely possible, which suggests that other sources of S. vesicarium inoculum that are currently neglected may be involved. The aim of this study is to investigate the possible wintering forms of Pleospora allii/S. vesicarium on pear wood and whether any spore-forming productions (conidial or ascosporic) might infect the green tissues of the plant in the following spring. Symptomatic fragments of woody tissue from a commercial pear orchard (in Ferrara, Emilia-Romagna, Italy) with a high BSP pressure (~40% incidence) were analysed. The results prove that pseudothecia and the maturation of ascospores of P. allii also develop on one-year-old branch cankers of pear trees, thus representing an additional source of inoculum. In conclusion, the pruning of affected branches and removal of relative residues should be preventatively performed in order to improve BSP management and control.

PbAGL7-PbNAC47-PbMYB73 complex coordinately regulates PbC3H1 and PbHCT17 to promote the lignin biosynthesis in stone cells of pear fruit.

Lignification of the cell wall in pear (Pyrus) fruit results in the formation of stone cells, which affects the texture and quality of the fruit. However, it is still unclear that how different transcription factors (TFs) work together to coordinate the synthesis and deposition of lignin. Here, we examined the transcriptome of pear varieties with different stone cell contents and found a key TF (PbAGL7) that can promote the increase of stone cell contents and secondary cell wall thicknesses. In addition, PbAGL7 can facilitate the expression level of lignin biosynthesis-related genes and accelerate the lignin biosynthesis in pear fruit and Arabidopsis. However, PbAGL7 did not directly bind to the promoters of PbC3H1 and PbHCT17 which are crucial genes involved in lignin biosynthesis. On the other hand, yeast two-hybrid (Y2H) library showed that PbNAC47 and PbMYB73 interacted with PbAGL7 in the nucleus. PbNAC47 and PbMYB73 also increased the stone cell and lignin contents, and upregulated the expressions of PbC3H1 and PbHCT17 by binding to the SNBE and AC elements, respectively. Moreover, PbNAC47 also interacted with PbMYB73 to form PbAGL7-PbNAC47-PbMYB73 complex. This complex significantly activated the expression levels of PbC3H1 and PbHCT17 and promoted lignin biosynthesis to form stone cells in pear fruit. Overall, our study provides new insights into the molecular mechanism of TFs that coordinately regulate the stone cell formation in pear fruit and extend our knowledge to understand cell wall lignification in plants.

Dynamic Analysis of UPLC-MS/MS for Sugar and Organic Acid Components of Pears with Different Flesh Texture Types During Development

Pears are popular among consumers for their juicy and delicious taste. In this study, the sugar and organic acid compositions of pear fruits with different texture types during development were determined by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), and fruit texture traits were determined by a texture analyzer. The results showed that the dominant sugar in soft and crispy types of pear fruits was fructose. The main difference between pears was the second-highest sugar component; glucose content was higher in crispy-flesh pear fruits while sucrose content was higher in soft-flesh pear fruits. The composition of organic acid components in both texture types of pear fruits was similar. The turning points of changes in the content of sucrose, sorbitol, glucose and quinic acid were different between different-textured pear varieties. A Pearson correlation analysis showed that sugar and organic acid components were significantly correlated with single fruit weight and soluble solid contents (SSCs), respectively. There was a high correlation among texture traits, individual sugars and organic acids. A partial least squares discriminant analysis (PLS-DA) VIP score plot showed that the differential traits with scores greater than 1 were total soluble sugars/total organic acids (TSSs/TAs), fracture and malic acid/citric acid (MA/CA), which could distinguish pear fruits of different texture types better and reflect the uneven quality differences among pear fruits adapted to different origins. The comprehensive analysis results of the flesh texture parameters and sugar and organic acid components are in line with objective reality and will provide a reference for quantitative indicators of the sensory evaluation of pear varieties as well as for molecular mechanism research on trait differences.

Positive effects of yeast soluble cell wall polysaccharide on fruit postharvest control through resistance response

Yeast-derived cell wall polysaccharides possess numerous biological activities, but their application in postharvest preservation is rarely reported. The aim of this research was to investigate the effects of Kluyveromyces marxianus soluble cell wall polysaccharide (SCWP) on preventing the infection of Penicillium expansum in pear fruit. The results showed that K. marxianus SCWP treatment could significantly improve the resistance of pear fruit to P. expansum, with respect to Saccharomyces cerevisiae-derived SCWP. Composition of both SCWPs was mannan with the main chains consisting of a → 6)-α-D-Manp-(1 → unit and the branch structure formed by → 2)-α-D-Manp-(1 except that K. marxianus SCWP took on a shorter side chain and a rougher surface than S. cerevisiae SCWP. In addition, mechanisms of K. marxianus SCWP on stimulating resistance response were associated with the apparent oxidative burst, increased gene expression and enzyme activity of antioxidant and defense systems in pear fruit. Our findings suggest that K. marxianus SCWP can be used as an innovative and promising candidate for preventing postharvest fungal decay and extending fruit shelf life.

PePalA/B/C are required for virulence and patulin biosynthesis by regulating the PePacC-processing proteolytic activity in Penicillium expansum

Abstract Background The Pal/Rim signaling pathway is crucial for fungal responses to ambient pH conditions. It comprises the transcription factor PacC/Rim101 and six upstream Pal proteins. While the role of PacC has been extensively studied, there is limited information on the functions of the upstream Pal proteins. Results In the genome of Penicillium expansum, genes encoding the endosomal membrane complex (PalA/B/C) were identified. Among these, only the expression of PePalB, not PePalA or PePalC, is pH-dependent. Subcellular localization and functional analyses showed that PePalA/B/C are localized to the cytosol and peripheral punctate structures. Deletion of PePalA/B/C resulted in reduced growth and conidiation of P. expansum across various pH conditions. The virulence of the ΔPePalA/B/C mutant was significantly reduced in pear and apple fruits. Additionally, the mutants exhibited a loss of patulin production under both acidic and alkaline conditions and the down-regulation of genes in the patulin biosynthetic cluster. pH shift experiments further demonstrated that PePalA/B/C are essential for both the PePacC expression and the pH-dependent proteolytic activation of PePacC. Conclusions These findings highlight the significant roles of PePalA/B/C in regulating growth, conidiation, virulence, and patulin production in P. expansum, thereby enhancing our understanding of the regulatory mechanisms underlying the Pal/Rim signaling pathway.

New Nanovesicles from Prickly Pear Fruit Juice: A Resource with Antioxidant, Anti-Inflammatory, and Nutrigenomic Properties.

Plant-derived nanovesicles represent a novel approach in the field of plant-derived biomaterials, offering a sustainable and biocompatible option for various biomedical applications. The unique properties of these vesicles, such as their ability to encapsulate bioactive compounds, make them suitable for therapeutic, cosmetic, and nutraceutical purposes. In this study, we have, for the first time, successfully bio-fabricated vesicles derived from Opuntia ficus-indica (FicoVes) using an efficient and cost-effective method. Characterized by a size of approximately of 114 nm and a negative zeta potential of -20.9 mV, FicoVes exhibited excellent biocompatibility and hemocompatibility, showing no reduction in the viability of human and animal cells. Our results showed that FicoVes possess significant antioxidant properties as they reduced ROS generation in TBH-stimulated cells. FicoVes displayed anti-inflammatory properties by reducing the expression of pro-inflammatory cytokines (Il 1β, TNF α) and enhancing the expression of anti-inflammatory cytokines (IL4, IL10) following an inflammatory stimulus. Furthermore, FicoVes accelerated epithelial wound closure in L929 fibroblast monolayers in a dose-dependent manner, highlighting their potential role in tissue repair. This study establishes FicoVes as a promising candidate for nutrigenomic applications, particularly in the context of inflammation-related disorders and wound healing. Further research, including in vivo studies, is essential to validate these findings and fully explore their therapeutic potential.

Identification of Candidate Genes Associated with Flesh Firmness by Combining QTL Mapping and Transcriptome Profiling in Pyrus pyrifolia.

Flesh firmness is an important quality of pear fruits. Breeding cultivars with suitably low flesh firmness is one of the popular pear breeding goals. At present, SNP markers related to pear flesh firmness and genes affecting flesh firmness are still uncertain. In this study, a QTL analysis was performed, and the result showed that the position of 139.857 cM in lineage group 14 (LG14) had the highest average logarithm of odds (3.41) over two years. This newly discovered locus was identified as a flesh firmness-related QTL (qFirmness-LG14). The 'C/T' SNP was found in corresponding Marker1512129. The 'C' genotype is the high-firmness genotype, which is a dominant trait. The average firmness of fruits with genotype C is 21.4% higher than genotype without the C genotype. Transcriptome profiling was obtained between 'Zaoshengxinshui' and 'Qiushui' at five time points. Three candidate genes in the interval of qFirmness-LG14 might affect firmness. A gene of xyloglucan endotransglucosylase 1 (PpXTH1) was upregulated in 'Qiushui' at all five time points. Two transcription factors (PpHY5 and PpERF113) were upregulated in 'Zaoshengxinshui', which might be negative regulatory genes for high flesh firmness. The transcriptome results also isolated a large number of cell wall-related genes (e.g., Pectate lyase, Pectin acetylesterase, Pectin methylesterase, and 4-coumarate-CoA ligase) and transcription factors (e.g., ERF, WRKY). These genes are all potential upstream and downstream genes related to flesh firmness. In conclusion, this study provides valuable insights into the QTLs and molecular mechanisms associated with fruit firmness in Pyrus pyrifolia.

Exogenous Nitric Oxide Induces Pathogenicity of Alternaria alternata on Huangguan Pear Fruit by Regulating Reactive Oxygen Species Metabolism and Cell Wall Modification.

Black spot caused by Alternaria alternata is one of the most common postharvest diseases in fruit and vegetables. A comprehensive investigation into its pathogenicity mechanism is imperative in order to propose a targeted and effective control strategy. The effect of nitric oxide (NO) on the pathogenicity of A. alternata and its underlying mechanism was studied. The results showed that treatment with 0.5 mM L-1 of sodium nitroprusside (SNP) (NO donor) increased the lesion diameter of A. alternata in vivo and in vitro, which was 22.8% and 13.2% higher than that of the control, respectively. Exogenous NO treatment also induced endogenous NO accumulation by activating nitric oxide synthase (NOS). In addition, NO triggered an increase in reactive oxygen species (ROS) levels. NO enhanced activities and gene expression levels of NADPH oxidase (NOX), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX), and glutathione reductase (GR). Moreover, NO stimulated cell wall degrading enzymes by activating the corresponding gene expression in vivo and in vitro. These results suggested that exogenous NO promoted the pathogenicity of A. alternata by inducing ROS accumulation and activating antioxidants and cell wall degrading enzymes. The present results could establish a theoretical foundation for the targeted control of the black spot disease in pear fruit.