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Here, the intensity and ratio of superoxide anion (O 2 • ), hydrogen peroxide (H 2 O 2 ) and hydroxyl anion (OH •- ) formation along the in vitro shootlets of four pear ( Pyrus communis L.) rootstocks (i.e., Pyrodwarf, OH × F40, OH × F69 and OH × F333) were scrutinized under E. amylovora inoculation, over 144 hpi. Furthermore, following identifying the most tolerant and susceptible pear rootstocks (i.e., OH × F69 and OH × F40, respectively), the dynamic expression profiles of three ROS-scavenging enzymatic genes including superoxide dismutase ( SOD ), Catalase ( CAT ) and ascorbate peroxidase ( APX ) were elucidated in response to E. amylovora , over 96 hpi. The highest disease tolerance was observed in OH × F69, and OH × F333, Pyrodwarf and OH × F40 occupied the next descending positions, respectively. Furthermore, the O 2 •- generation rates were almost similar in all the pears studied, though the accumulation of H 2 O 2 and OH •- and intensities thereof were considerably distinctive and significantly followed up the levels of disease resistance. Comparing to the controls (0 hpi), in both susceptible and tolerant pear rootstocks, transcription activity of SOD , CAT , and APX genes were overall stimulated with relatively high abundance over 24, 48, 72 and 96 hpi, though some fluctuations were also recorded. Our ROS results, altogether, indicated that E. amylovora is capable enough to stimulate ROS formation in pear, though its progress is extremely dependent upon the susceptibility ratio of the plant. Lastly, the particular expression patterns and different response time of three genes designated that pear rootstocks differentially activates genes encoding antioxidant enzymes to mitigate the possible damage of ROS during E. amylovora invasion.

Anthocyanin concentration is the key determinant for red skin color in pear fruit. However, the molecular basis for development of red skin is complicated and has not been well-understood thus far. \"Starkrimson\" (Pyrus communis L.), an introduced red pear cultivated in the north of China and its green mutant provides a desirable red/green pair for identification of candidate genes involved in color variation. Here, we sequenced and annotated the transcriptome for the red/green color mutant at three stages of development using Illumina RNA-seq technology. The total number of mapped reads ranged from 26 to 46 million in six libraries. About 70.11-71.95% of clean reads could be mapped to the reference genome. Compared with green colored fruit, a total of 2230 differentially expressed genes (DEGs) were identified in red fruit. Gene Ontology (GO) terms were defined for 4886 differential transcripts involved in 15 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Three DEGs were identified as candidate genes in the flavonoid pathway, LAR, ANR, and C3H. Tellingly, higher expression was found for genes encoding ANR and LAR in the green color mutant, promoting the proanthocyanidin (PA) pathway and leading to lower anthocyanin. MYB-binding cis-motifs were identified in the promoter region of LAR and ANR. Based on these findings, we speculate that the regulation of PA biosynthesis might be a key factor for this red/green color mutant. Besides the known MYB and MADS transcription families, two new families, AP2 and WRKY, were identified as having high correlation with anthocyanin biosynthesis in red skinned pear. In addition, qRT-PCR was used to confirm the transcriptome results for 17 DEGs, high correlation of gene expression, further proved that AP2 and WARK regulated the anthocyanin biosynthesis in red skinned \"Starkrimson,\" and ANR and LAR promote PA biosynthesis and contribute to the green skinned variant. This study can serve as a valuable new resource laying a solid foundation for functional gene identification in the anthocyanin pathway of red-skinned pear and provide a good reference for relevant research on molecular mechanisms of color variation in other pear species.

Southern Europe is home to two naturally occurring pear species: the European wild pear (Pyrus pyraster (L.) Burgsd.) and the almond-leaved pear (P. spinosa Forssk.). In addition to these two species, the cultivated pear (P. communis L.) is also grown throughout Europe. Since the cultivated pear is one of the most widespread fruits in Europe, gene flow between the cultivated species and their wild relatives is to be expected. The aim of this study was to determine the genetic diversity of natural populations and whether gene flow from the cultivated pear can alter the genetic composition of wild pear populations. We collected samples from 21 populations of P. pyraster and 22 populations of P. spinosa as well as 24 cultivars of P. communis. DNA fingerprinting based on nine microsatellite markers (SSR) was used to analyze the genetic diversity and structure of the wild pear populations and to assess the relationship between wild and cultivated pears. In general, we found a higher genetic diversity of P. pyraster compared to P. spinosa. In three Mediterranean P. pyraster populations, significant cultivated-to-wild gene flow was observed, whereas in P. spinosa it was rare and only observed in a few individuals. Furthermore, in regions where the ecological niches of the two wild pear species overlap, hybrids between them were also found. This study provides valuable insights into the genetic variability of these species and can significantly advance their use in sustainable forest management, conservation, and breeding programs.

Pyrus communis L. is a vital fruit tree known for its nutritional and economic importance. Thus, for humans, it is an essential element for their balanced nutritional diet, as it contains the major dietary fibers, vitamins, and minerals. All of these nutritionally important aspects decrease with the impact of disease fire blight. Erwinia amylovora is a causative agent of fire blight. This infection causes a considerable loss in the production of Pyrus communis L. Annually, approximately 50% of pear fruit in Pakistan is misplaced because of these illnesses. Therefore, we propose nanotechnology remediation to treat pear plants and obtain the desired yield. In this regard, an experiment was designed to treat infected plants with different concentrations of silver–selenium nanocomposites, which was based on a literature review that indicated the antimicrobial activities of silver and selenium nanoparticles. Silver–selenium nanocomposites were prepared using a green synthesis method, and their synthesis was confirmed using characterization techniques. The experiment was performed at a farmhouse in Chakwal district, Punjab, Pakistan. The experimental results showed increased morphological, physiological, and biochemical parameters. In this regard, the best treatment remained at 50 ppm for the Ag–Se nanocomposite, which improved the plant in different aspects. At the same time, they have improved fruit metrics, such as vitamin C, pH, and juice content. Thus, these results show a possible improvement in enhancing the resistance against fire blight by using green-synthesized Ag–Se NCs. Further studies are needed to understand fully the molecular mechanisms and actions of Pyrus communis L. in treating fire blight disease and to establish the optimal treatment plan.

Application of edible coatings is a suitable method to maintain the quality and reduce post-harvest losses in fresh vegetables and fruits. Pear fruits being climacteric have a short shelf life, and coating is considered as one of the most popular techniques to prolong its shelf life.The present study evaluates the effect of optimized edible coatings containing soy protein isolate (SPI) in combination with additives like hydroxypropyl methylcellulose (HPMC) and olive oil on ‘Babughosha’ Pears ( Pyrus communis L.) stored at ambient temperature (28 ± 5 °C and 60 ± 10% RH). Four different coatings optimized by response surface methodology study were used in the present experiment. The results of the present study shows that the optimized edible coatings help retain the firmness of fruits and lowered the moisture loss. The tested combination of coating could also withhold the levels of ascorbic acid, chlorophyll and sugar contents in the treated fruits. Activities of enzymes associated with fruit softening (β-galactosidase, polygalacturonase, pectin methyl esterase) showed delayed peaks. Amongst all treatments, T1 (SPI 5.0%, HPMC 0.40%, Olive oil 1%, Potassium sorbate 0.22%) and T2 (SPI 5.0%, HPMC 0.40%, Olive oil 0.98% Potassium sorbate 0.20%) were found to have pronounced effect on retention of nutritional quality in pears. Observations of shelf-life extension established that T2 (SPI 5.0%, HPMC 0.40%, Olive oil 0.98% Potassium sorbate 0.20%) was successful in extending shelf-life of pear fruits up to 15 days, as compared to 8 days for untreated pear fruits.

Estimating maturity in pome fruits is a critical task that directs virtually all postharvest supply chain decisions. This is especially important for European pear ( Pyrus communis) cultivars because losses due to spoilage and senescence must be minimized while ensuring proper ripening capacity is achieved (in part by satisfying a fruit chilling requirement). Reliable methods are lacking for accurate estimation of pear fruit maturity, and because ripening is maturity dependent it makes predicting ripening capacity a challenge. In this study of the European pear cultivar ‘d’Anjou’, we sorted fruit at harvest based upon on-tree fruit position to build contrasts of maturity. Our sorting scheme showed clear contrasts of maturity between canopy positions, yet there was substantial overlap in the distribution of values for the index of absorbance difference ( I AD ), a non-destructive spectroscopic measurement that has been used as a proxy for pome fruit maturity. This presented an opportunity to explore a contrast of maturity that was more subtle than I AD could differentiate, and thus guided our subsequent transcriptome analysis of tissue samples taken at harvest and during storage. Using a novel approach that tests for condition-specific differences of co-expressed genes, we discovered genes with a phased character that mirrored our sorting scheme. The expression patterns of these genes are associated with fruit quality and ripening differences across the experiment. Functional profiles of these co-expressed genes are concordant with previous findings, and also offer new clues, and thus hypotheses, about genes involved in pear fruit quality, maturity, and ripening. This work may lead to new tools for enhanced postharvest management based on activity of gene co-expression modules, rather than individual genes. Further, our results indicate that modules may have utility within specific windows of time during postharvest management of ‘d’Anjou’ pear.

Key message We describe a semi in vivo pollination technique to determine the compatibility relation between different pear cultivars. This assay provides a valuable addition to existing tools in GSI research. The gametophytic self-incompatibility (GSI) system in Pyrus inhibits fertilization by pollen that shares one of the two S- alleles of the style. Depending on their S- locus genotype, two pear cultivars therefore either show a cross-compatible, semi-compatible or incompatible interaction. Because GSI greatly influences seed and fruit set, accurate knowledge of the compatibility type of a cultivar is key for both pear fruit production and breeding. Currently, compatibility relations between different pear cultivars are generally assessed via S- genotyping. However, this approach is restricted to the currently known S- alleles in pear, and does not provide functional assessment of the level of (self-)incompatibility. We here present an optimized semi in vivo pollination assay, that enables quantitative analysis of (self-)incompatibility in pear, and that can also serve useful for more fundamental studies on pollen tube development and pollen–style interactions. This assay involves in vitro incubation of cut pollinated styles followed by microscopic counting of emerging pollen tubes at a specific time interval. The validity and selectivity of this method to determine compatibility interactions in pear is demonstrated in the cultivars “Celina” and “Packham’s Triumph.” Overall, this technique constitutes a valuable tool for quantitatively determining in vivo pollen tube growth and (cross-)compatibility in pear.

Background The vigour and precocity of trees highly influences their efficiency in commercial production. In apple, dwarfing rootstocks allow high-density plantings while their precocious flowering enables earlier fruit production. Currently, there is a lack of pear ( Pyrus communis L.) rootstocks that are equivalent to the high yielding apple rootstock ‘M9’. For the efficient breeding of new Pyrus rootstocks it is crucial to understand the genetic determinants of vigour control and precocity. In this study we used quantitative trait loci (QTLs) analysis to identify genetic loci associated with the desired traits, using a segregating population of 405 F1 P. communis seedlings from a cross between ‘Old Home’ and ‘Louise Bonne de Jersey’ (OHxLBJ). The seedlings were grafted as rootstocks with ‘Doyenne du Comice’ scions and comprehensively phenotyped over four growing seasons for traits related to tree architecture and flowering, in order to describe the growth of the scions. Results A high density single nucleotide polymorphism (SNP)-based genetic map comprising 597 polymorphic pear and 113 apple markers enabled the detection of QTLs influencing expression of scion vigour and precocity located on linkage groups (LG)5 and LG6 of ‘Old Home’. The LG5 QTL maps to a position that is syntenic to the apple ‘Malling 9’ (‘M9’) Dw1 locus at the upper end of LG5. An allele of a simple sequence repeat (SSR) associated with apple Dw1 segregated with dwarfing and precocity in pear and was identified in other pear germplasm accessions. The orthology of the vigour-controlling LG5 QTL between apple and pear raises the possibility that the dwarfing locus Dw1 arose before the divergence of apple and pear, and might therefore be present in other Rosaceae species. Conclusion We report the first QTLs associated with vigour control and flowering traits in pear rootstocks. Orthologous loci were found to control scion growth and precocity in apple and pear rootstocks. The application of our results may assist in the breeding process of a pear rootstock that confers both vigour control and precocity to the grafted scion cultivar.

Pear ( Pyrus communis L.) stands out as a prominent fruit species in temperate regions worldwide. The Çoruh River basin, nestled in the lower Caucasus in Türkiye, serves as a valuable repository of pear germplasm. To elucidate the genetic structure of pear populations in this region, 84 village pear cultivar genotypes (land races) from six villages, sample garden collections (SCC), and wild Panta root stock populations were analysed using eleven microsatellite markers. Genetic diversity and structure analyses indicated that village pear cultivar populations exhibit substantial genetic diversity and admixture. This diversity is attributed to local farming practices such as phenotypic selection and widespread dispersal of clonal materials. The genetic structure analysis, combined with the identification of private alleles, indicates that the pear genetic resources in the Çoruh river basin likely has originated from two gene pool sources, specifically the Meydancık and Camili village pear traditional cultivar populations. The Camili village pear cultivar population as a new in situ genetic reserve site has been proposed. Despite the existence an ex situ conservation site, the study suggests inadequateness of SCC as an ex situ site in capturing the full extent of genetic diversity of village pear cultivar genetic resources. Thus, enriching the genetic diversity in the SCC ex situ site is essential for effective pear genetic resource conservation in the Çoruh river basin. These findings contribute valuable insights for the development of targeted conservation strategies, ensuring the preservation of pear genetic resources in this region.

The effect of composite edible films containing soy protein isolate (SPI) in combination with additives like hydroxypropyl methylcellulose (HPMC) and olive oil on ‘Babughosha’ pear ( Pyrus communis L.) stored at ambient temperature (28 ± 5 °C and 60 ± 10% RH) was evaluated using Response surface methodology (RSM). A total of 30 edible coating formulations comprising of SPI (2–6%, w/v), olive oil (0.7–1.1%, v/v), HPMC (0.1–0.5%, w/v) and potassium sorbate (0–0.4% w/v) were evaluated for optimizing the most suitable combination. Quality parameters like weight loss%, TSS, pH and titrable acidity of the stored pears were selected as response variables for optimization. The optimization procedure was carried out using RSM. It was observed that the response variables were mainly effected by concentration of SPI and olive oil in the formulation. Edible coating comprising of SPI 5%, HPMC 0.40%, olive oil 1% and potassium sorbate 0.22% was found to be most suitable combination for pear fruit with predicted values of response variables indicated as weight loss% 3.50, pH 3.41, TSS 11.13 and TA% 0.513.