Chilling requirement (CR) is a key determinant for bud dormancy release in peach [Prunus persica (L.) Batsch]. To examine the genetic basis of CR and facilitate the breeding of climate-resilient varieties, we conducted a genome-wide association study (GWAS) on a diverse panel of 213 peach accessions with their CR phenotypes. The CR phenotypic data collected over 3 years demonstrated high heritability (H 2  = 0.86), indicating a strong genetic component. The GWAS analysis identified 52 SNPs associated with CR traits, with major loci clustered on chromosome 1 (17.3-21.2 and 43.7-47.3 Mb) and chromosome 2 (5.2-13.9 Mb), thereby both confirming established loci in the DAM cluster and identifying novel genetic regions. By focusing on regions exhibiting stable CR associations across years and which could be successfully validated by Kompetitive Allele Specific PCR (KASP) assays, 13 candidate CR-related genes were identified. Two highly robust KASP markers derived from loci in chromosome 1 were developed and validated. These markers effectively discriminated between low (<400 h) and high (≥900 h) CR phenotypes. The combined use of these two markers achieved 95.5% accuracy in identifying extreme low-CR phenotypes (CR < 300 h) in peach accessions. The identification of genes linked to these robust markers of CR-related loci and the analysis of their expression during dormancy identified three potentially related with CR trait modulation: a receptor-like protein kinase, a protein kinase and a BED-type zinc finger domain-containing protein. This study provides useful molecular tools for marker-assisted breeding for low-CR peaches and new insights into the complex regulatory network of CR.

DNA methylation is a key epigenetic regulator of fruit ripening, yet its influence on peach postharvest quality is poorly understood. This study took “Xiahui 5” peach to analyze the effects of the DNA methylation inhibitor 5-azacytidine (5-azaC) treatment on fruit phenotype, metabolite levels, and gene expression, and quantified important postharvest indicators related to nutritional quality and disease resistance. In terms of nutritional quality, 5-azaC enhanced peel coloration and anthocyanin accumulation, delayed the decomposition of soluble sugars such as sorbitol, and reduced the content of volatile compounds like linalool and lactones. In terms of resistance quality, 5-azaC treatment has a direct inhibitory effect on M. fructicola, induced the activities of antioxidant enzymes and defense enzymes, increased the accumulation of defense-related substances such as total phenols, flavonoids, and anthocyanins, and enhanced the lignification of the cell wall to form a physical barrier. In addition, 5-azaC increased the calcium content and regulated calcium signal-related gene expression. In terms of plant hormones, 5-azaC treatment reduced ABA and ETH levels in early fruit senescence and increased JA and SA levels in later stages. These findings show that 5-azaC delays senescence and enhances disease resistance by remodeling the hormonal network, highlighting the dual role of DNA methylation in balancing fruit senescence and disease defense, and offering theoretical support for postharvest fruit preservation and disease control.

Background The postharvest preservation of peach (Prunus persica) fruit has always been a concern, and research on the mechanisms behind peach fruit softening is important for improving postharvest preservation technologies. The WRKY gene family is a multitude of transcription factors in plants that broadly participate in the regulation of various biological processes. Nonetheless, the roles of WRKY family members in peach fruit softening remain largely unknown. Results Here, we report a peach WRKY family member PpWRKY13 that may be involved in peach fruit softening through the regulation of fruit softening-related gene PpXTH33. Investigations of gene expression levels across different peach organs revealed that PpWRKY13 may play a critical role in peach fruit during storage. A multiple alignment analysis indicated that the PpWRKY13 protein contains a WRKY domain and structural features diagnostic of the Group IIa subfamily. A subcellular localization assay demonstrated that the pBI121-PpWRKY13-EGFP fusion protein is highly localized in the nuclei of tobacco leaf cells, suggesting that PpWRKY13 is characteristic of a transcription factor. We identified a candidate target gene, PpXTH33, of PpWRKY13 using DNA affinity purification sequencing. Additionally, a luciferase assay and transient overexpression suggested that PpWRKY13 may activate the transcription of PpXTH33. Conclusions In summary, PpWRKY13 may activate the transcription of PpXTH33 and function as a putative modulator of peach fruit softening. This work advances our knowledge of peach fruit softening mechanisms.

As the abundant phenolic substance in peach fruit, chlorogenic acid (CGA) has various biological activities and is an important target for improving the nutritional and resistance qualities. Nevertheless, the gene functions and regulatory mechanisms of CGA biosynthesis in peach fruit are poorly understood. Using gene expression patterns from different developmental stages and different peach cultivars, one structural gene PpHCT5 was identified as being involved in CGA biosynthesis. An in vitro enzyme activity assay confirmed that the PpHCT5 protein catalyzed the biosynthesis of caffeoyl CoA and quinic acid into CGA. The in vivo functional validation confirmed that PpHCT5 overexpression increased CGA accumulation in transgenic plants, including peach, tomato, and tobacco. Furthermore, upstream transcription factors of PpHCT5 were identified. PpMYB62 and PpbHLH14 activated PpHCT5 expression by directly binding promoter MBS or G-box elements, thereby inducing CGA accumulation in peach fruit. Additionally, PpMYB308 interactions with PpbHLH14 promoted the activating effect of PpbHLH14 on PpHCT5, thereby positively regulating CGA biosynthesis. Thus, a regulatory network of PpMYB and PpbHLH transcription factors to modulate the PpHCT5-mediated CGA biosynthesis pathway was constructed. It will be useful for elucidating the complex mechanisms underlying CGA biosynthesis and provide a theoretical basis for the development of resistance and increased CGA content breeding in peach.

This paper presents a novel high-order cell-centered Lagrangian scheme for 2D compressible hydrodynamics by bridging the multi-moment constrained finite volume method (MCV) [16, 51, 52] with a nodal Riemann solver. This scheme (denoted by LMCV) not only maintains high-order accuracy as MCV but also inherits the conservation and robust properties of the nodal Riemann solver. On the one hand, the MCV employs and evolves both the point-values (PV) at cell vertexes and the volume-integrated averages (VIA) on computational mesh, which ensures the rigorous numerical conservation and establishes an adequate foundation for the computation of Lagrangian fluxes with high accuracy. On the other hand, we developed a 2D Riemann solver based on EUCCLHYD [24], it takes fully advantage of numerical formulations from high-order scheme and accomplishes the compatibility between the mesh movement and numerical fluxes. The main new features of the solver are the introduction of a new set of jump and balance conditions. The jump condition provides a high-accurate formulation linking the surface pressure of each cell to its nodal velocity, while the balance condition ensures nodal conservation and stabilizes the velocity field without losing accuracy. More intriguing is that our nodal solver can be regarded as a natural high-order extension of the HLLC and the HLLC-2D [41] solvers. The comparison between these solvers better demonstrates our innovative approach in addressing the difficulties encountered in constructing 2D high-order Lagrangian schemes. A variety of numerical experiments are carried out to illustrate the accuracy and robustness of the algorithm.

Elevated cadmium (Cd) exposure poses a significant threat to plant growth and productivity. Phosphorus (P) alleviates Cd toxicity in plants to some extent; however, the mechanisms underlying this effect remain poorly understood. In this study, the effect of phosphorus on cadmium toxicity was investigated using Kandelia obovata (S., L.) Yong roots from physiological and proteomic perspectives. Under Cd stress, P application was associated with enhanced root activity and antioxidant enzyme functions (peroxidase and superoxide dismutase) within the roots of Kandelia obovata, while concurrently reducing malondialdehyde levels. Proteomic analysis identified 494 and 110 differentially expressed proteins in the cadmium stress vs. the untreated control (Cd vs. CK) group and the exogenous phosphorus addition under Cd stress vs. the phosphorus-only treatment (HP + Cd vs. HP) group, respectively. Enrichment results indicated that P treatment was associated with metabolic adjustments related to cell wall biosynthesis, protein synthesis, and intracellular transport. These coordinated responses suggest that P supplementation may improve Cd tolerance in K. obovata roots.

Peach aroma is a key quality trait that differs markedly between melting flesh (MF) and stony hard (SH) cultivars during postharvest ripening. This study investigated the metabolic and molecular foundations of aromatic divergence between melting flesh (MF; 'HujingMilu' and 'Yulu') and stony hard (SH; 'Xiacui' and 'Qinwang') cultivars. Following an initial physiological screening of four cultivars, 'HujingMilu' (HJ) and 'Xiacui' (XC) were selected as representative models for in-depth metabolomic and transcriptomic investigations. These two cultivars exhibited highly contrasting aroma accumulation patterns during postharvest storage, providing an ideal model for deciphering the molecular basis of peach aroma biosynthesis. Partial Least Squares Discriminant Analysis (PLS-DA) and odor activity value (OAV) evaluations identified 13 key volatiles, including gamma-decalactone, gamma-hexalactone, and hexanal, as primary determinants of the aromatic differences. Integrated transcriptomic and weighted gene co-expression network analysis (WGCNA) revealed that enhanced aroma formation in 'HJ' fruit was associated not only with the up-regulation of LOX pathway genes, but also with the coordinated activation of upstream glycerol metabolism, fatty acid synthesis, and beta-oxidation pathways. Notably, a group of ethyleneresponsive factors (PpERF1/2/3/4/5) exhibited a dramatic transcriptional burst in 'HJ', highly synchronized with the peaks of ethylene production and volatile accumulation. These PpERFs were identified as hub nodes that potentially provide dual regulation by activating terminal biosynthetic genes and ensuring precursor supply through the modulation of upstream metabolic pathways. In contrast, the systemic suppression of the ethyleneERF axis in 'XC' fruit maintains this transcriptional cascade in a low-activity state. Collectively, these findings provide an evidence-based mechanistic model for the differential aroma accumulation in peach and offer promising molecular targets for breeding cultivars with improved flavor quality and postharvest performance.

IntroductionOrchard-floor mulching is widely used for weed suppression in perennial fruit systems, yet its effects on soil fungal communities and their links to soil nutrient status and fruit traits remain insufficiently understood.MethodsHere, we conducted a 6-year field experiment in a peach orchard to compare three orchard-floor management practices: barrier fabric (BF), hairy vetch (HV), and ryegrass (RG). Soil physicochemical properties, fruit traits at harvest, and soil fungal communities were evaluated, and treatment-responsive fungal modules were identified by integrating differential abundance analysis, indicator species analysis, and co-occurrence network analysis.Results and discussionCompared with the other treatments, HV was associated with higher fruit weight and a higher total sugar-to-total acid ratio (TS/TA). Mulching treatments significantly altered soil physicochemical properties and fungal community composition, whereas fungal alpha diversity showed limited overall responses. Three candidate treatment-responsive fungal modules were preferentially enriched under BF, HV, and RG, respectively, and differed in both taxonomic composition and their associations with soil nutrient variables. Fruit weight was positively correlated with soil NO3--N and NH4+-N and negatively correlated with soil pH, whereas flavor-related traits were positively correlated with AN, NH4+-N, NO3--N, and dissolved organic carbon (DOC). Overall, long-term mulching was associated with shifts in soil fungal assemblages, and these assemblages were linked to soil nutrient conditions and fruit traits. This study provides a fungal community perspective on how orchard-floor management may be associated with soil–plant interactions in peach orchards.

This study determined the phenolic content and antioxidant activity in petals of 160 peach germplasm resources (including ornamental, fresheating, processing, and rootstock types) and conducted a comprehensive evaluation of their antioxidant capacity. The results showed that neochlorogenic acid and hyperoside were present in all germplasms, whereas substances such as catechin and chlorogenic acid were absent in some germplasms. Ornamental peach exhibited a significantly higher total anthocyanin content (TAC) than all other categories (p < 0.05), rootstock materials showed extensive phenotypic variation. The total phenolic content (TPC) and total flavonoid content (TFC) were significantly and strongly positively correlated with ferric reducing antioxidant power (FRAP), 1,1diphenyl2picrylhydrazyl (DPPH) radical scavenging capacity, and 2,2'azinobis(3ethylbenzothiazoline6sulfonic acid) (ABTS) radical scavenging capacity (r = 0.40~0.66, p < 0.0001), whereas TAC showed a strong positive correlation only with ABTS (r = 0.75). Using the membership function method, the top 20 germplasms with the highest antioxidant capacity were screened.

Glyphosate is a common herbicide in peach orchards, but its long-term impacts on tree physiology and soil health remain unclear. This study aims to comprehensively evaluate the effects of long-term glyphosate application on the growth of peach trees, soil properties, and microbial communities. In this study, through a six-year continuous positioning experiment, combined with the analysis of physiological and biochemical indexes and high-throughput sequencing technology, the multi-dimensional impacts of glyphosate on the peach tree-soil system were systematically revealed. The results showed that compared with the control group, the glyphosate treatment group significantly inhibited the photosynthetic function of peach trees. The net photosynthetic rate, stomatal conductance, and water use efficiency decreased synchronously, accompanied by an imbalance in the antioxidant system. The glyphosate-derived metabolite aminomethylphosphonic acid (AMPA) accumulated in soil at concentrations markedly exceeding those of the parent compound, inducing soil acidification, organic matter loss, and diminished available potassium, while simultaneously stimulating urease activity. The diversity and structure of the soil microbial community changed significantly. Shifts in the abundance of dominant bacterial communities, such as Proteobacteria, showed significant correlations with soil nutrients and enzyme activities. Long-term glyphosate application negatively affects peach tree physiology and soil ecological function. These findings provide critical insights for optimizing herbicide use and soil management practices in peach orchards.

Late-spring frost events severely damage low-chill peach blossoms, causing significant yield losses. Although 5-aminolevulinic acid (ALA) enhances cold tolerance through the PpC3H37-PpWRKY18 module, the regulatory mechanism of ALA on PpC3H37 remains to be elucidated. Using yeast one-hybrid screening with the PpC3H37 promoter as bait, we identified PpDof9 as a key interacting transcription factor. A genome-wide analysis revealed 25 PpDof genes in peaches (Prunus persica). These genes exhibited variable physicochemical properties, with most proteins predicted as nuclear-localized. Subcellular localization experiments in tobacco revealed that PpDof9 was localized to the nucleus, consistent with predictions. A synteny analysis indicated nine segmental duplication pairs and tandem duplications on chromosomes 5 and 6, suggesting duplication events drove family expansion. A conserved motif analysis confirmed universal presence of the Dof domain (Motif 1). Promoter cis-element screening identified low-temperature responsive (LTR) elements in 12 PpDofs, including PpDof1, PpDof8, PpDof9, and PpDof25. The quantitative real-time PCR (qRT-PCR) results showed that PpDof1, PpDof8, PpDof9, PpDof15, PpDof16, and PpDof25 were significantly upregulated under low-temperature stress, and this upregulation was further enhanced by ALA pretreatment. Our findings demonstrate ALA-mediated modulation of specific PpDof TFs in cold response and provide candidates (PpDof1, PpDof9, PpDof8, PpDof25) for enhancing floral frost tolerance in peaches.

Phytohormones are known to have important regulatory roles in floral bud dormancy. Comparative metabolomics (LC-MS/MS) was used to examine the profiles of phytohormones during peach floral bud dormancy and demonstrated significant differences between the low and high chilling requirement (CR) peach varieties, ‘Changlvmaotao1’ and ‘Jinxiu’, respectively. Of the 88 phytohormones tested, 70 were detected in floral buds, but 44 were present in levels above threshold detection limits. Most hormones levels were relatively low or static during endodormancy, with only six showing significant changes, including jasmonic acid (JA) and its derivatives, jasmonoyl-L-isoleucine (JA-ILE) and N-[(-)-Jasmonoyl]-(L)-valine (JA-Val), 1-Aminocyclopropanecarboxylic acid, abscisic acid, 1-amino-cyclopropane-1-carboxylic acid and the gibberellin, GA53. However, 28 significant changes were observed in ecodormancy, including auxins, cytokinins and salicylic acid. The levels of JA and its derivatives, JA-ILE and JA-Val, all showed differential levels throughout dormancy, suggesting their important and diverse roles in the regulation of dormancy. The varieties of differing CR showed substantially differing phytohormone profiles during endo- and eco-dormancy, including 6-Benzyladenosine, L-tryptophan, 3-oxo-2-(2-(Z)-Pentenyl) cyclopentane-1-hexanoic acid, cis(+)-12-Oxophytodienoic acid, 3-oxo-2-(2-(Z)-Pentenyl) cyclopentane-1-butyric acid, and gibberellin GA1. Our preliminary findings indicate hormones and related metabolites which are likely to have regulatory roles in the maintenance or progression of bud dormancy in peach varieties of differing CR and which are therefore promising targets for further study and as physiological markers in peach breeding efforts.

Thinned peach fruit represents a substantial source of polyphenols, primarily due to its early developmental stage. Utilizing ultrasound-assisted extraction optimized through a Box–Behnken design, we determined the optimal extraction parameters to be 45 min, 360 W, a liquid-to-solid ratio of 15:1 mL/g, and a temperature of 70 °C. Under these conditions, the total phenolic content (TPC) achieved was 1.12 g GAE/kg FW, with an extraction efficiency of 97.06%. Additionally, an extensive evaluation of 179 peach cultivars revealed that wild accessions possessed significantly higher polyphenol content, including TPC, total flavonoid content (TFC), and total anthocyanin content (TAC), alongside enhanced antioxidant activities as measured by ferric reducing antioxidant power (FRAP), 2,2′-Azino-di-3-ethylbenzthiazoline Sulfonic Acid (ABTS), and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays, in comparison to landraces and cultivated varieties. Notably, the wild accession ‘Gansu Peach 2’ exhibited the highest TPC (2.61 g GAE/kg FW), whereas the landrace ‘Early White Blossom Peach’ demonstrated the highest TFC (137.32 g RTE/kg FW), TAC (25.30 g PAE/kg FW), and antioxidant capacity. Additionally, as expected, significant positive correlations (0.73 < r < 0.96) were also observed between polyphenol components and antioxidant activities (p < 0.0001). This study establishes a foundational framework for the utilization of thinned peach fruit as valuable polyphenol-rich resources.

Brown rot, caused by Monilinia fructicola, is a major fungal disease that causes substantial losses in peach production. To explore the molecular mechanisms of resistance to M. fructicola, comparative analyses were conducted between resistant ‘Zhonghujing’ (ZHJ) and susceptible ‘C18-2-11-8’ (C18) cultivars using integrated physiological, transcriptomic, and metabolomic approaches. M. fructicola infection induced reactive oxygen species (ROS) production in peach fruits, with stronger and earlier antioxidant and defense responses observed in 'ZHJ' compared to 'C18'. The differentially expressed genes (DEGs) were predominantly enriched in plant-pathogen interactions, hormone signaling transduction, and phenylpropanoid biosynthesis pathways, and the disease resistance was related to the calcium, salicylic acid, and jasmonic acid signals. It is worth noting that higher contents of anthocyanin and lignin were identified in the disease-resistant varieties. Flavonoids, such as quercetin, myricetin, and taxifolin, inhibited M. fructicola growth to a certain extent. In particular, taxifolin had the greatest inhibitory effect and displayed a strong affinity with the virulence target protein of M. fructicola, is expected to become a natural agent against brown rot. These findings theoretically elucidates the molecular mechanisms underlying peach resistance to brown rot and provides novel insights into the development of flavonoid-based natural fungicides against peach brown rot.

Accumulation of anthocyanin pigments is a primary determinant of fruit quality in peach (Prunus persica L. Batsch). The recessive blood-flesh trait (bf), identified in French cultivars was first mapped on chromosome 4. However, the underlying gene is yet to be identified. In this study, the genetic, molecular and transcriptional bases of the bf trait were investigated. Blood-flesh cultivars showed high levels of cyanidin-3-glucoside and cyanidin-3-rutinoside in the fruit mesocarp about 45-60 days after anthesis. Fine mapping coupled to a positional cloning strategy mapped the bf locus to an 80-kb interval on peach linkage group 4. The sequence polymorphism analysis of genes present in this interval allowed the identification of only one candidate gene for bf a deletion of 21-bp in exon 3 of a PSAK-like gene (PSAK:photosystem I subunit K). A specific marker for the deletion was developed and validated in different genetic backgrounds. An expression study of PpPSAK as well as analysis of structural, regulatory and photosynthesis related genes was performed to compare cultivars with blood-flesh (Montarsa) and without blood-flesh (S11332) during fruit development from 60 days after blooming until fruit maturity. Differently expressed of PpPSAK in the flesh of bf fruit was correlated with expression of anthocyanin biosynthesis structural genes. A protein-protein interaction study was performed and is presented with an open discussion on functional pathways in peach.

Sucrose phosphate synthase (SPS) is pivotal for sucrose biosynthesis in peach fruit, yet its regulatory mechanisms underlying 5-aminolevulinic acid (ALA)-mediated sucrose accumulation remain unclear. This study revealed that exogenous ALA significantly enhances sucrose content and SPS activity in early-ripening peach (Prunus persica 'Zaoxing No.2'). Yeast one-hybrid (Y1H) screening identified PpAP2-like, an AP2/ERF transcription factor, which exhibited nuclear localization, transcriptional activation activity. The result of Y1H showed that PpAP2-like interacted with the promoter of PpSPS2. ALA positively regulates PpAP2-like to promote PpSPS2 expression. Dual-luciferase and GUS reporter systems confirmed that ALA positively regulates PpAP2-like to promote PpSPS2 expression. Furthermore, ALA treatment upregulated PpAP2-like expression, which correlated positively with SPS activity and sucrose accumulation during fruit development. These findings elucidate a molecular pathway whereby ALA promotes sucrose biosynthesis via PpAP2-like-mediated transcriptional regulation of PpSPS2, providing critical insights for optimizing fruit quality and advancing molecular breeding strategies in peach.

‘Huang Cui’ (HC) is a lack climacteric stony hard peach fruit with long storage period and easy to transport. Studies found that exogenous ethylene treatment can improve the quality of stony hard peach ‘HC’, solving the persistent issue that it has a lighter flavor. However, the molecular basis of the effect of ethylene on the quality of ‘HC’ is still unclear. It is important to reveal the metabolic mechanism of quality factors through key genes. In this study, we characterized the main fruit quality after ethylene treatment. It was found that while the texture and aroma of fruit were improved, and the contents of soluble solid, soluble sugar and organic acid remained stable after ethylene treatment. Furthermore, the combined analysis of transcriptome and quality trait data was performed to reveal the underlying metabolic mechanisms of the changes in fruit quality after ethylene treatment. As a result, four genes associated with cell wall metabolism were considered as potential key genes for fruit texture change. Five type genes related to aroma changes were considered as potential key genes that are associated with α-linolenic acid and linoleic acid metabolism after ethylene treatment. This study provides theoretical and practical cornerstones for regulating and improving the quality of stony hard peach ‘HC’.

Monilinia fructicola-induced brown rot disease can lead to substantial post-harvest losses in peach fruit, with major economic effects. Calcium chloride (CaCl2) treatment has been reported to mitigate brown rot in peaches, but the underlying molecular mechanisms involved remain largely unexplored. In this study, preharvest application of CaCl2 significantly reduced the incidence of brown rot in post-harvest peach fruit. Transcriptome analysis identified 208 differentially expressed genes during the 12-48 h post-infection period in CaCl2-pretreated peach that were predominantly associated with plant hormone signal transduction, plant-pathogen interaction, flavonoid biosynthesis, and amino sugar and nucleotide sugar metabolism. Preharvest CaCl2 treatment raised calcium levels and Ca2 +-sensor activity in infected fruit, boosting PpRBoh activity and transcription coincided with a reactive oxygen species burst. Moreover, CaCl2 treatments also increased methyl jasmonate (MeJA) content via upregulating expression of PpLCAT3, PpLOX, PpAOS, PpAOC, PpOPR, and PpJMT in alpha-linolenic acid metabolism, thereby activating the jasmonic acid (JA) signaling pathway. Conversely, CaCl2 treatment decreased indole-3-acetic acid (IAA) content via downregulating expression of PpTAA1, PpALDH, PpYUCCA1 in tryptophan metabolism, leading to a suppression of the IAA signaling pathway. Additionally, CaCl2 treatment elevated the levels of pathogenesis-related proteins, flavonoids, total phenolics and anthocyanins by stimulating phenylpropanoid metabolism. Furthermore, the weighted gene co-expression network analysis identified six gene modules of co-expresses genes, with blue and green modules significantly linked to the levels of flavonoids, total phenolics, anthocyanins and the activities of CHS, F3H, DFR, ANS, and BZ1, showing that polyphenolics biosynthesis is particularly related to the JA signaling gene PpMYC2 and the JAs biosynthesis genes. Consequently, CaCl2 sprays offer a promising alternative to chemical fungicides for mitigating peach fruit loss caused by M. fructicola infection during storage.

Fragaria viridis exhibits S-RNase-based gametophytic self-incompatibility (SI), which is governed by a polymorphic S-locus including two S-RNase alleles along with multiple S-locus F-box (SLF) genes. However, SI reaction in flowers triggers a complex cascade involving numerous genes unlinked to S-locus, the mechanisms underlying their mediation of SI response remain unclear. In this study, a phosphatase FviPP2Ac and a NADPH oxidase FviRbohH were observed to highly express in pollen and relate to reactive oxygen species (ROS) and SI response. Self-pollen tubes exposed to S-RNase exhibited downregulation of FviPP2Ac and upregulation of FviRbohH. FviPP2Ac played a negative role in pollen tube growth, as supplying FviPP2Ac protein with pollen culture resulted in inhibited pollen tube elongation and reduced ROS content at pollen tube tips. Conversely, FviRbohH acted as a positive regulator, since knockdown of FviRbohH expression in pollen using antisense oligodeoxynucleotides (as-ODN) led to growth suppression, accompanied by decreased ROS levels at pollen tube tips. FviPP2Ac bound to S-RNase in an S-haplotype-independent manner, whereas no interaction was detected between FviRbohH and S-RNase. FviPP2Ac interacted with FviRbohH and inhibited its activity, while S-RNase weakened this interaction without S-haplotype selectivity. Furthermore, we proposed a S-RNase-FviPP2Ac-FviRbohH-ROS signaling pathway model, which provides new clue for revealing a regulatory mechanism about ROS production in SI response of self-pollination in Fragaria viridis.

This study investigates the aroma differences among various peach and nectarine varieties by sensory evaluation, electronic nose (E-nose) analysis, and metabolomics. Peach is a significant fruit crop in China, and identifying unique fragrances is essential for germplasm selection and cultivar improvement. Six peach and nectarine varieties were collected from the National Peach Germplasm Repository in Nanjing, China. Sensory evaluation revealed significant differences in aroma and taste, with ”Zi Jin Hong 3” and “Bai Mi Pan Tao” showing high scores for aroma, sweetness, and overall sensory quality, while “Tachibanawase” had the lowest overall impression score. E-nose analysis showed distinct response values among varieties, with sensors W1S, W1W, and W5S exhibiting the highest sensitivity. GC-MS identified 446 metabolites, including esters and terpenes. PCA and OPLS-DA differentiated metabolite profiles among varieties, revealing significant differences in metabolite expression. The integration of these techniques provides a comprehensive understanding of aroma differences, highlighting the potential for identifying unique germplasms for breeding high-quality cultivars with charming flavor, and offering a theoretical foundation for raw material selection and process optimization in the deep-processing industry of peach fruits in future research.