Lightweight multi-classification pear fruit high-precision detection model in complex orchard scenes

A PpTIFY5A/10A-PpTGA2.1-L complex delaying fruit senescence via salicylic acid antagonized ethylene and jasmonic acid in sand pear

In recent years, escalating global temperatures have adversely affected the yield and quality of horticultural crops. Red pears (Pyrus spp.), prized for their vibrant pigmentation, derive their characteristic coloration primarily from anthocyanin accumulation. Light and temperature are important environmental factors regulating anthocyanin biosynthesis. Light induces the accumulation of anthocyanins in red pear; however, the specific molecular mechanism by which elevated temperatures inhibit anthocyanin biosynthesis in red pear remains unclear. The integration nodes of the light and temperature signals also remain to be discovered. In this study, we identified a high-temperature-responsive repressor, pear HEAT SHOCK FACTOR B2b (PpHsfB2b), which exhibits rapid upregulation under high-temperature treatment. A stable transformation system using pear calli demonstrated that PpHsfB2b functions as a repressor of anthocyanin biosynthesis. PpHsfB2b directly bound to the promoters of anthocyanin biosynthesis-promoting factors MYB transcription factor 10 (PpMYB10) and ELONGATED HYPOCOTYL 5-LIKE (PpHY5L), inhibiting their expression. Additionally, we identified a key light-temperature signaling node gene, B-box transcription factor 16 (PpBBX16), through which PpHsfB2b exerts a dual inhibitory effect on anthocyanin biosynthesis. PpHsfB2b not only interacted with PpBBX16 to attenuate transcriptional activation of downstream genes PpMYB10 and UDP-glucose: flavonoid 3-O-glucosyltransferase (PpUFGT), but also suppressed anthocyanin accumulation by competitively weakening the PpHY5L-PpBBX16 interaction. These insights deepen our understanding of high-temperature-regulated fruit pigmentation and identify PpBBX16, a critical light-temperature signaling node, providing a molecular framework for the color change of pear fruits under increasing temperatures.

Rational fertilization directly affects the fruit quality of the Korla fragrant pear. However, the variation patterns of fruit appearance and texture indicators under different N-P2O5-K2O ratios are complex, and redundancy among high-dimensional indicators restricts the practical application of quality discrimination and fertilization traceability. In this study, Korla fragrant pear fruits harvested under eight fertilization treatments (including the control) were selected as research materials. Significant differences existed in nutrient composition and application rate among treatments: no N-P2O5-K2O was applied in the CK treatment; for treatments H1–H7, nitrogen (N) application rate ranged from 396.36 to 524.2 g·plant−1, phosphorus (P2O5) from 326.08 to 652.17 g·plant−1, and potassium (K2O) from 450.67 to 1200.08 g·plant−1, with the most prominent differences observed in P-K ratios and application rates. On this basis, 12 appearance and flesh texture indicators were determined, including single-fruit weight, longitudinal diameter, transverse diameter, fruit shape index, pericarp thickness, sclereid content, hardness, adhesiveness, cohesiveness, springiness, gumminess and chewiness. Three machine-learning algorithms, namely Random Forest (RF), Extreme Learning Machine (ELM) and K-Nearest Neighbor (KNN), were used to construct fruit quality discriminant models. The results showed that the RF model achieved the optimal discriminative performance, with accuracy values of 0.876 and 0.865 for the training and validation sets, respectively. Seven core quality indicators, including sclereid content and longitudinal diameter, were screened via feature-importance intersection analysis. The reconstructed RF model based on this indicator set exhibited nearly no loss in discriminative accuracy despite a ~42% reduction in indicator quantity, providing theoretical and technical support for quality grading, fertilization traceability and precision fertilization of Korla fragrant pear.

Metabolomic and transcriptomic analysis reveals the impact of fruit bagging on cork spot disorder in ‘Akizuki’ pear fruit

Transcriptional activation of PbrFLOT1 by PbrWRKY33 contributes to pear resistance against Botryosphaeria dothidea.

PbbHLH41 negatively regulates iron deficiency tolerance in pear.

Abscisic acid, stress and ripening-induced genes (ASRs) play crucial roles in fruit maturation, and the isolation, identification, and functional characterization of these genes have been extensively studied in plants. 'Guanyang' snow pear is a high-quality pear cultivar with distinct regional characteristics in Guangxi. However, the gene responsible for ASR1 and its specific functional attributes remain unidentified. In this study, PpyASR1 was successfully isolated from 'Guanyang' snow pear fruits. This gene was found to exhibit specific expression during fruit development, with its expression level following an initial increase followed by a subsequent decrease. Subcellular localization analysis revealed that the protein product of the PpyASR1 gene predominantly localizes within the nucleus, supporting its role as a transcription factor regulating maturation and senescence in fruit tissues. Virus-induced gene silencing experiments demonstrated that suppressing of PpyASR1 gene expression in 'Guanyang' snow pear fruit significantly delayed senescence-associated deterioration. Compared to the control group, the treated fruits exhibited higher firmness, lower ABA content, reduced ethylene production, lower soluble solid content, and higher titratable acidity. Transient overexpression of PpyASR1 in 'Guanyang' snow pear resulted in markedly accelerated fruit senescence and postharvest deterioration. Compared to controls, these fruits showed reduced firmness, increased ABA content and ethylene production, and lower titratable acidity, whereas no significant difference in soluble solids content was detected. The current findings provide valuable insights into the storage characteristics of 'Guanyang' snow pear and establish a theoretical foundation for understanding the potential role of PpyASR1 in regulating fruit senescence and postharvest deterioration.

Pear (Pyrus) stone cells, a major determinant of fruit quality, form via cell wall lignification. The plant hormone jasmonic acid (JA) plays a pivotal role in regulating secondary cell wall formation, although the underlying molecular mechanisms remain unclear. Here, we demonstrated that JA positively regulates stone cell lignification via respiratory burst oxidase homolog F (PuRBOHF)-dependent reactive oxygen species (ROS) production. The NAC transcription factor PuNAC43 acts as a central mediator, enhancing JA-induced ROS accumulation and lignin deposition. PuNAC43 directly binds to promoters of the PuRBOHF and lignin biosynthesis genes (cinnamoyl-CoA reductase 1, PuCCR1; cinnamyl alcohol dehydrogenase 2, PuCAD2), thereby enhancing their transcription. Additionally, PuMYC2, a central MYC transcription factor in the JA signaling pathway, mediates JA-induced upregulation of PuNAC43 function. PuMYC2 binds directly to the PuNAC43 promoter, activating its expression. Furthermore, PuMYC2 recruits the bHLH transcription factor PubHLH93 through promoter binding and protein-protein interaction, forming a heterodimeric complex that synergistically enhances the activation of PuNAC43. Notably, PuMYC2-mediated transcriptional activation depends on JA levels. Our findings reveal a JA-responsive transcriptional complex, PuMYC2-PubHLH93-PuNAC43, that elevates the transcription of PuRBOHF and lignin-related genes to drive stone cell formation, thereby revealing pivotal mechanisms underlying JA-induced lignification in pear fruit.

Improving pear fruit quality without yield loss through 3D point cloud-based estimation of reasonable fruit load

Grapholita molesta is a major fruit tree pest. Host plant volatiles act as chemical cues to mediate female oviposition. This study investigated the recognition of ovipositing G. molesta females for pear volatile blends based on age-dependent olfactory plasticity. Results showed that mated females exhibited a distinct reproduction-flight coordination window optimized at 2 days of age. Olfactory gene expression in female antennae depended on the postmating age. Nine odorant receptor (OR) genes were upregulated at 3 vs. 9 days postmating (DPM), with stronger antennal responses to trace-level odorants. RNA interference targeting ORs, especially GmolOR46, reduced antennal responses and oviposition preference at 3 DPM. Mature pears emitted more volatiles than apples, especially after mechanical injury. Females at 3 DPM were attracted to volatiles from intact or injured mature pears, particularly at high concentrations. They increased field moth catches. Our findings reveal that pear volatiles have potential as attractants for G. molesta.

Dwarfism is crucial for intensive cultivation and labor-saving management in modern orchards. However, the molecular mechanisms underlying pear tree dwarfing remain largely unclear. Here, we performed comparative transcriptome analysis between dwarf pear germplasm and pear cultivar 'Cuiguan'. The dwarf pear germplasm exhibited significantly shorter internode and branch length compared to 'Cuiguan'. Histological analysis revealed that cortical cells in the dwarf pear germplasm were disordered and irregular, and longer than those of 'Cuiguan'. Comparative transcriptome analysis of shoot apex from young shoots of the dwarf germplasm and 'Cuiguan' was conducted and a total of 13,169 differentially expressed genes (DEGs) were identified. Functional enrichment analysis revealed that functional terms related to plant hormone biosynthesis and signal transduction were overrepresented in DEGs. Genes involved in brassinosteroid (BR) and gibberellin (GA) biosynthesis were downregulated in the dwarf germplasm. DEGs involved in transcription regulation and cell wall formation were also identified, which play potential roles in tree dwarfing. In addition, expression level of genes within the chromosomal region containing PcDw locus, which has been reported as the dominant gene controlling dwarf trait, was investigated in both the dwarf pear germplasm and 'Cuiguan'. Based on comparative analysis, nine genes in this region are considered to be closely associated with dwarf traits. The dwarf germplasm and 'Cuiguan' showed distinct tissue structure, with dwarfism mainly associated with defects in cell division and elongation. Comparative transcriptome analysis identified a set of DEGs involved in plant hormones biosynthesis, signaling and transport, as well as cell wall biosynthesis, modification and degradation. By integrating transcriptome data with information related to the PcDW locus, nine genes were identified as key candidates. Overall, the results of this study provide insights for understanding the mechanisms underlying pear dwarfism.

Pear fire blight, caused by the bacterium Erwinia amylovora, is a destructive disease affecting Rosaceae plants. Although insect transmission is well-documented, most studies have focused on pollinators, with limited attention to psyllids. Chinese pear psyllid (Cacopsylla chinensis) is a major piercing-sucking pest of pear trees, yet its role in the transmission of E. amylovora remains unclear. Here, we investigated the distribution of E. amylovora in and on C. chinensis and the synergistic damage (i.e., C. chinensis creates invasion wounds and nutrient-rich niches for E. amylovora via piercing-sucking feeding, while the pathogen enhances the vector's fitness to promote disease spread). Field and laboratory assays confirmed severe synergistic symptoms. E. amylovora was isolated from all life stages and body parts of C. chinensis, with significantly higher pathogen loads and virulence in internally harbored strains compared to external ones. Specifically, E. amylovora loads in nymphs were significantly higher than those in adults, and strains from the digestive system and female reproductive organs caused a 3- to 9-fold higher disease index on pear leaves at 7 days post-inoculation compared to body surface isolates. This study provides evidence that C. chinensis acts as a crucial vector for E. amylovora in Xinjiang, laying a theoretical basis for the precise integrated management of this pest-disease complex.

The occurrence of pear Valsa canker caused by Cytospora pyri poses a serious threat to the healthy and sustainable development of the Korla fragrant pear industry. To effectively control the disease, endophytic strains were isolated from the bark of Korla fragrant pear trees and screened for strong antagonistic activity against the pathogen. The selected strain was identified based on morphological characteristics and 16S rRNA phylogenetic analysis. Its biocontrol potential and functional traits were further evaluated, along with its growth-promoting ability assessed through in vitro tests and preliminary tomato pot experiments. Results showed that a total of 264 endophytic isolates were obtained from 200 pear tissue samples using dilution plating and tissue separation methods. Among them, strain FB-4 exhibited significant inhibition against C. pyri. Morphological observations and phylogenetic analysis identified the strain as Bacillus velezensis, named FB-4. The cell-free supernatant inhibited conidial germination and mycelial growth of the pathogen by 88.21% and 85.51%, respectively, and showed preventive and curative efficacies of 74.49% and 58.97% against pear Valsa canker. In vitro assays indicated that FB-4 could produce indole-3-acetic acid, protease, amylase, and cellulase, and demonstrated abilities to solubilize inorganic phosphate and synthesize siderophores. Inoculation with FB-4 bacterial suspension promoted the growth of tomato seedlings, with higher concentrations yielding more pronounced effects. In conclusion, strain FB-4 represents a dual-functional biocontrol agent with both antagonistic and plant-growth-promoting properties.

PpbHLH14.1-PpCCD4a regulatory module modulates lutein accumulation and peel colouration in pear (Pyrus pyrifolia).

Impact of NPK soil fertilization on the metabolomic profile of pear (Pyrus communis L.) fruit juice using NMR approach

Catechol 1, 2-dioxygenase AaCHD is essential for the detoxification of phenolic acids in pear fruit peel by Alternaria alternata

Lipid and phenylpropanoid metabolic pathways are involved in the defense response of pear fruit to Alternaria alternata infection

Black spot disease is a significant disease during the growth period of pear trees. The species and pathogenicity of Alternaria fungi causing black spot disease in Anhui Province are still unclear. In this study, through phylogenetic analysis of multi-gene tandem sequences, pathogens causing pear black spot disease (PBS) in Anhui Province were identified, primarily Alternaria alternata, Alternaria gaisen and Alternaria tenuissima, with A. alternata being the dominant species (41.18%). The single nucleotide polymorphism (SNP) density of Alt a1 was much higher than that of other genes, and the codon bias was affected by both natural selection and mutation. The codon bias and the amino acid ratio of Alt a1 in A. alternata and A. gaisen were highly consistent, and A. tenuissima was quite different from them. The pathogenicity of A. alternata was significantly negatively correlated with the daily mycelia growth rate, dry weight of mycelia and alternariol production, and significantly positively correlated with tenuazonic acid (TeA) and tentoxin production. TeA might be the main virulence factor in the pathogenic process of A. alternata. This study presents novel ideas for classifying Alternaria fungi and provides a theoretical basis for establishing prevention and control technologies for PBS control and toxin reduction. © 2026 Society of Chemical Industry.

Endogenous H2O2 participated in the ethylene-dependent ripening and senescence process of horticultural fruit as a secondary messenger; however, the molecular mechanism beneath such a phenomenon has not been fully clarified until recently. By a conjoint analysis of metabolite, enzyme activities, gene expression profiles in AsA-GSH cycle of 'Kolar' pear, PbrAPX14 might act as a negative factor in the ethylene-mediated H2O2 accumulation. PbrAPX14, located in cytosol, would reduce H2O2 invitro and invivo, inhibit ethylene production, and thus fruit ripening and senescence. After analysing the expression profiles of the differentially expressed transcription factors (TFs) followed by experimental validation, the nuclear PbrIDD2 could directly bind to the cis-acting element (core motif: TTTGTCG) in PbrAPX14 promoter, activate its expression and thus enhance the H2O2-scavenging capacity of fruit/calli, which was associated with the mitigated ethylene evolution and fruit ripening and senescence. Further study explored that the H2O2-mediated post-translational S-sulfenylation of Cys48 residue in PbrAPX14, which mitigated its function, existed invitro and invivo, and was upregulated by ethylene, facilitating endogenous H2O2 accumulation. Overall, our results implied that both transcriptional and post-translational regulation of PbrAPX14, which were (in)directly under the control of ethylene, functioned in pear ripening and senescence process via regulating endogenous H2O2 level.