Pear (Pyrus bretschneideri), a valuable widely cultivated fruit, faces significant economic losses due to black spot disease caused by Alternaria alternate (Fr.) Keissl. Trihelix transcription factors (TFs) are crucial in regulating plant defense and autoimmunity. This study aimed to analyze the trihelix transcription factor (GT) genes within pear through genome-wide identification, phylogenetic, gene structure, synteny, and cis-acting elements analyses. Among the 31 trihelix genes, 28 were on 12 known chromosomes, while the remaining 3 were located on unknown chromosomes. These genes were categorized into five clades: SIP1, GTγ, GT1, GT2 and SH4, containing 7, 2, 9, 11 and 2 genes, respectively. Synteny analysis indicated eight duplicated gene pairs. Based on the expression pattern of PbGT genes in seven tissues from the database, the PbGT genes of the GT2 clade were selected for further investigation. The quantitative reverse transcriptase–polymerase chain reaction confirmed that PbrGT5, PbrGT6, PbrGT15 and PbrGT16 correlated with black spot disease resistance. Notably, the salicylic acid (SA) treatment significantly upregulated the expression levels of PbrGT10, PbrGT13, PbrGT15 and PbrGT23. Among these, PbrGT15 showed the highest induction to both SA and black spot infection. Subcellular localization demonstrated that PbrGT15 functions as a nuclear protein. Virus-induced gene silencing of PbrGT15 increased pear plants' susceptibility to black spot disease, indicating its pivotal role in enhancing resistance. These results indicated that PbrGT15 positively regulated black spot disease resistance in pears.

Postharvest ripening is correlated to the quality and shelf life of European pear fruit. In this study, the effects of peppermint extract on fruit phenotype, related physiological activities, and aroma components during postharvest ripening of the European pear variety ‘Packham’s Triumph’ were examined. Fruit treated with 2.0 g L⁻¹ peppermint extract for 12 h showed delayed softening by 4 d compared with that of the untreated control group. The peak values of ethylene and respiratory rate in fruit were reduced to a certain extent after peppermint extract treatment; however, the peppermint extract did not delay the occurrence of the respiratory climacteric peak. Peppermint extract treatment also did not significantly increase the content of the characteristic peppermint aroma in pear fruit. Further, widely targeted metabolome analysis revealed 298 significantly different metabolites, with flavonoids (40%) and lipid compounds (15%) accounting for the highest proportion on the first day after treatment. The Kyoto Encyclopedia of Genes and Genomes pathway result showed significant enrichment in the metabolic pathways of biosynthesis of flavonoid, isoflavonoid, flavone and flavonol, linoleic acid, and alpha-linolenic acid metabolism following peppermint extract treatment. The combined analysis of transcriptome and metabolome data showed significant enrichment in linoleic acid metabolism and alpha-linolenic acid metabolism on the first, third, and fifth days after peppermint extract treatment. This study indicates that peppermint extract mainly affects the pear fruit softening process in the early stage after treatment.

Agrobacterium tumefaciens, a destructive pathogen causing crown gall disease, results in substantial agricultural losses. Traditional chemical and existing biocontrol methods are limited by environmental pollution, pesticide resistance, and low efficacy, while bacteriophages emerge as a promising alternative due to their high host specificity, environmental compatibility, and low resistance risk. In this study, we isolated and characterized a lytic phage (PAT-A) targeting A. tumefaciens, evaluating its biological traits, genomic features, and biocontrol potential. The host strain A. tumefaciens CL-1 was isolated from cherry crown gall tissue and identified by 16S rDNA sequencing. Phage PAT-A was recovered from orchard soil via the double-layer agar method, showing a tadpole-shaped morphology (60 nm head diameter, 30 nm tail length) under transmission electron microscopy (TEM). Nucleic acid analysis confirmed a double-stranded DNA genome, susceptible to DNase I but resistant to RNase A and Mung Bean Nuclease. PAT-A exhibited an optimal MOI of 0.01, tolerated wide pH and temperature ranges, but was sensitive to UV (titer declined after 15 min of irradiation) and chloroform (8% survival at a 5% concentration). Whole-genome sequencing revealed a 44,828 bp genome with a compact structure, and phylogenetic/collinearity analyses placed it in the Atuphduvirus genus (Autographiviridae). Biocontrol experiments on tobacco plants demonstrated that PAT-A significantly reduced crown gall incidence. Specifically, simultaneous inoculation of PAT-A and A. tumefaciens CL-1 resulted in the lowest tumor incidence (12.0%), while pre-inoculation of PAT-A 2 days before pathogen exposure achieved an incidence rate of 33.3%. In conclusion, PAT-A is a novel strictly lytic phage with favorable biological properties and potent biocontrol efficacy against A. tumefaciens, enriching phage resources for crown gall management and supporting phage-based agricultural biocontrol strategies.