Pyrus Communis Research Articles

Genome-wide analysis of the PME gene family reveals its role in suppressing fruit lignification in pear

In pears, the presence of stone cells adversely affects fruit quality. Pectin methylesterase (PME) plays various roles in plant biology, including lignin biosynthesis. However, only a limited fraction has been functionally characterized, and the distribution and function of PME in many Rosaceae trees remain unexplored. In this study, we identified 396 putative PME family candidate genes, with 81 in Pyrus bretschneideri, 92 in Malus domestica, 62 in Fragaria vesca, 65 in Prunus mume, 15 in Pyrus communis, and 81 in Pyrus pyrifolia. Leveraging insights from model plants, we categorized PME family genes into four groups. Additionally, the evolution of the PME gene family was shaped by various gene duplication events, primarily dispersed duplication, influenced by purifying selection. A specific gene, Pbr031522.1, designated PbPME35, emerged as a candidate associated with lignin biosynthesis in pear fruits, supported by RNA-seq data. The role of PbPME35 in repressing lignification was validated through its overexpression in pear callus and Arabidopsis. Overall, our findings highlight the ability of PbPME35 to reduce lignin content in pear fruit by downregulating the expression levels of lignin biosynthesis genes. These findings provide new insights into the characteristics of PME genes and their role in regulating lignification in pear fruits.

Introduction of a diverse genetic background of Pyrus into Malus through intergeneric hybridization.

Wide hybridizations across species and genera have been employed to enhance agriculturally important traits in crops. Within the tribe Maleae of the Rosaceae family, different genera and species exhibit several traits useful for increasing diversity and gene pool through hybridization. This study aimed to develop and characterize intergeneric hybrid individuals between Malus and Pyrus. Through seed germination, shoot multiplication, and rooting in vitro, acclimatized seedlings showing vegetative growth on their own roots were obtained from crosses of Malus × domestica pollinated by Pyrus communis, P. bretschneideri, and the Pyrus interspecific hybrid (P. communis × P. pyrifolia). Comparative analysis of leaf morphology, flow cytometry, and molecular genotyping confirmed the hybrid status of the individuals. Genome-wide genotyping revealed that all the hybrid individuals inherited genomic fragments symmetrically from the Malus and Pyrus parents. To the best of our knowledge, this is the first report on the development of intergeneric hybrid seedlings between Malus × domestica and P. bretschneideri. Furthermore, the Pyrus interspecific hybrid individual served as a bridge plant for introducing the genetic background of P. pyrifolia into Malus × domestica. The results of this study provided a crucial foundation for breeding through intergeneric hybridization between Malus and Pyrus, facilitating the incorporation of valuable traits from diverse gene pools.

Pest categorisation of Lepidosaphes malicola.

The EFSA Panel on Plant Health performed a pest categorisation of Lepidosaphes malicola (Hemiptera: Diaspididae), the Armenian mussel scale, for the territory of the European Union, following commodity risk assessments of Prunus persica and P. dulcis plants for planting from Türkiye, in which L. malicola was identified as a pest of possible concern. L. malicola is a polyphagous insect of temperate and arid areas, feeding on more than 60 plant species belonging to 26 families. Important crops significantly affected by L. malicola in parts of Asia include stone fruits (Prunus armeniaca, P. persica), pome fruits (Malus domestica, Pyrus communis), grapes (Vitis vinifera), pomegranate (Punica granatum), walnuts (Juglans regia) and ornamental plants (Berberis spp., Cornus spp., Jasminum spp., Ligustrum spp.). L. malicola has two generations annually. The overwintered eggs hatch from late May to early June. First-instar nymphs crawl on the host plant for a short period, then settle to feed. Nymphs reach maturity in late summer or early autumn. Plants for planting, fruits and cut flowers provide potential pathways for entry into the EU. Host availability and climate suitability suggest that southern, central and some parts of northern EU countries would be suitable for the establishment of L. malicola. Despite being a pest in Armenia, Iran and Tajikistan, there is no evidence of it being a pest in Türkiye. L. malicola was detected in Bulgaria and Greece over 30 years ago, but there have been no records since, and its status is uncertain. Its ability to cause an impact in the EU is also uncertain. It is not listed in Annex II of the Commission Implementing Regulation (EU) 2019/2072. Phytosanitary measures are available to reduce the likelihood of entry. Except for the criterion of having an economic or environmental impact, for which there is great uncertainty, L. malicola satisfies all other criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Productivity and Fruit Quality of ‘FalstaffPBR’ Pear Variety Grafted on Different Rootstocks

‘FalstaffPBR’ is a pear variety released by CREA and New Plant in 2012. This study focused on the effects of various clonal rootstocks on the main productive and qualitative traits of ‘FalstaffPBR’ scion. The rootstocks used were ‘EMC’, ‘EMH’, and ‘BA29’ for quince (Cydonia oblonga) and pear ‘Farold 40’ (Pyrus communis). Plants were planted in 2009 with a layout that, depending on the used rootstock, varied between 60 and 120 cm on the row, according to the rootstock standard planting system, and 350 cm between rows. The average yield calculated in the trail field in the 4 years of production (2014–2017) was over 22.7 tons ha−1 on ‘BA29’, 22.8 tons ha−1 on ‘EMH’, 16.3 tons ha−1 on ‘Farold 40’, and 18.4 on ‘EMC’. Fruits of the plants grafted on ‘Farold 40’ always had a medium-to-high size, while fruits produced by the plants grafted onto ‘BA29’ have been larger in size since the first years of production. The plants grafted onto ‘EMH’ produced fruits with the highest percentage of red overcolor. The ‘EMH’ rootstock is optimal for ‘FalstaffPBR’ as it gives the plant an intermediate vigor between ‘BA29’ and ‘EMC’, and a good yield per hectare from the first planting years; the average fruit size is excellent.

Mechanism of Peppermint Extract-Induced Delay of 'Packham's Triumph' Pear (Pyrus communis L.) Postharvest Ripening.

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.

Rapid Determination of Different Ripening Stages of Occidental Pears (Pyrus communis L.) by Volatile Organic Compounds Using Proton-Transfer-Reaction Mass Spectrometry (PTR-MS).

Determination of Occidental pear (Pyrus communis) ripening is difficult because the appearance of Occidental pears does not change significantly during the ripening process. Occidental pears at different ripening stages release different volatile organic compounds (VOCs), which can be used to determine fruit ripeness non-destructively and rapidly. In this study, VOCs were detected using proton-transfer-reaction mass spectrometry (PTR-MS). Notably, data were acquired within 1 min. Occidental pears harvested at five separate times were divided into three ripening stages: unripe, ripe, and overripe. The results showed that the composition of VOCs differed depending on the ripening stage. In particular, the concentrations of esters and terpenes significantly increased during the overripe stage. Three ripening stages were clearly discriminated by heatmap clustering and principal component analysis (PCA). This study provided a rapid and non-destructive method to evaluate the ripening stages of Occidental pears. The result can help fruit farmers to decide the optimum harvest time and hence reduce their economic losses.

Smilax aspera L. Leaf and Fruit Extracts as Antibacterial Agents for Crop Protection

Smilax aspera L. (commonly known as sarsaparilla) is recognized for its composition rich in flavonoids, phenylpropanoids, steroidal saponins, stilbenoids, and tannins, exhibiting anti-inflammatory, cytotoxic, and antimicrobial properties. This study investigates the hydromethanolic extracts of its leaves and fruits through vibrational spectroscopy and gas chromatography–mass spectrometry, evaluating their potential as biorationals for safeguarding crops. Analysis of S. aspera leaf and fruit extracts revealed the presence of phytochemicals such as lactones and other furan derivatives. In vitro assessments against three phytopathogens—Erwinia amylovora, Pseudomonas syringae pv. actinidiae, and Xanthomonas campestris pv. campestris—demonstrated strong antibacterial activity, with minimum inhibitory concentration (MIC) values of 1500 μg·mL−1 for both extracts. Biofilm tests indicated that the leaf extract reduced biofilm formation by 78–85%, while the fruit extract led to a reduction of 73–92.5%. At a concentration of 750 µg·mL−1, the extracts caused a decrease in amylovoran synthesis by 41–58%. Additionally, noticeable alterations in membrane permeability were observed at MIC and MIC/2 doses. Subsequent in vivo trials conducted on Pyrus communis L. trees utilizing the combined aerial part extract yielded substantial protection against E. amylovora at a dose of 1500 μg·mL−1, reaching 80% wilting reduction for the leaf extract. The findings presented herein cast S. aspera extracts as a promising natural-based treatment against these bacterial phytopathogens.

Metabolic alterations in pear cultivars during storage at ambient conditions

Patharnakh’ (PN) (Pyrus pyrifolia Burm. Nakai) and ‘Punjab Beauty’ (PB) [Pyrus communis L. × Pyrus pyrifolia Burm. Nakai] are the leading low-chill pear cultivars of the subtropics of India. Diurnal temperature and relative humidity during the fruit harvest period are high, which considerably affects the shelf life of fruits. Fruits of ‘PN’ and ‘PB’ pear harvested at physiological maturity were stored for 16 days at ambient temperature, and the effects of the storage day interval on physical and qualitative parameters were studied. Both cultivars showed reductions in fruit firmness, physiological weight loss, total soluble solids, and juice acid content during storage. Activities of fruit softening enzymes such as polygalacturonase (PG), pectin methylesterase (PME), and cellulase were enhanced, whereas those of superoxide dismutase (SOD) were reduced during storage. Fruit firmness was negatively correlated with polygalacturonase, pectin methylesterase, PPO, and cellulase enzymes in both cultivars. In both cultivars, the increased browning of the fruit during storage was negatively correlated with total phenolic content and positively correlated with polyphenol oxidase activity during storage. ‘Patharnakh’ and ‘Punjab Beauty’ fruits maintain desirable quality parameters up to 6–12 days and 4–8 days, respectively, during storage at ambient conditions.

Wing buzzing as a mechanism for generating vibrational signals in psyllids (Hemiptera: Psylloidea).

Psyllids, or jumping plant lice (Hemiptera: Sternorrhyncha: Psylloidea), are a group of small phytophagous insects that include some important pests of crops worldwide. Sexual communication of psyllids occurs via vibrations transmitted through host plants, which play an important role in mate recognition and localization. The signals are species-specific and can be used to aid in psyllid taxonomy and pest control. Several hypotheses have been proposed for the mechanism that generates these vibrations, of which stridulation, that is, friction between parts of the forewing and thorax, has received the most attention. We have investigated vibrational communication in the European pear psyllid species Cacopsylla pyrisuga (Foerster, 1848) using laser vibrometry and high-speed video recording, to directly observe the movements associated with signal production. We describe for the first time the basic characteristics of the signals and signal emission of this species. Based on observations and analysis of the video recordings using a point-tracking algorithm, and their comparison with laser vibrometer recordings, we argue that males of C. pyrisuga produce the vibrations primarily by wing buzzing, that is, tremulation that does not involve friction between the wings and thorax. Comparing observed signal properties with previously published data, we predict that wing buzzing is the main mechanism of signal production in all vibrating psyllids.

Quantitative 2D fruit shape analysis of a wide range of pear genetic resources toward shape design breeding

The shape of a fruit is one of the main characteristics of fruit morphology, and its quantitative description is crucial to improve fruit quality. However, the shape of a pear fruit is relatively complex, and difficult to describe comprehensively. This study aimed to quantitatively analyze the morphological diversity of 2D fruit shapes of 276 cultivars, covering 6 groups including Pyrus pyrifolia, Pyrus bretschneideri, Pyrus ussuriensis, Pyrus sinkiangensis, Pyrus communis and interspecific hybridization, and discover shape traits with high heritability. Through an automated image processing method, the fruit contour was first accurately extracted, and then geometrical parameters and Fourier descriptors of the pear fruit shape were obtained. Furthermore, principal components (PCs) of the Fourier descriptors were analyzed, and the broad-sense heritability (H2) of the PCs and standardized width (WSD) were estimated. After that, the pear shape stability was calculated, and cultivars were clustered by their shape characteristics. This paper mainly discusses the longitudinal section, as the cross-section variation among cultivars is small. For the longitudinal section, the results showed more than 95 % of the two-dimensional shape variation can be explained by only six principal components; WSD20, WSD30 and PC1 have high H2; the shape stability of western pear was the lowest; a new class of shape was found by clustering the shape traits. The results indicated that the proposed pipeline can provide an objective and comprehensive quantitative description of pear fruit shape for a wide range of cultivars, which is necessary to discover the key genes determining pear shape. This approach is also beneficial for research on pear breeding and germplasm resource management.

Effect of herbal application on browning inhibition and physico-chemical quality of pear (Pyrus communis) slices

The main objective of the research study is to evaluate the effect of herbs (O. basilicum, O. vulgare, C. sinensis) extract-coated pear slices on its physiochemical quality attributes, discoloration rate, and browning enzyme activity in comparison with chemical (ascorbic acid) coated pear slices over 15 days at 4 ± 1 ℃. A significant difference (p < 0.05) between herbs and ascorbic acid-coated pear slices was obtained in terms of physiochemical quality attributes, whereby the highest variation was obtained in uncoated pear slices (control) and the least variation was observed in herbs-coated pear slices, more specifically C. sinensis spray, and dip (6 min) extract showed the highest inhibition of PPO/POD activity and the minimum browning index was noticeable throughout 15 days of storage. These findings showed that herbal extract coating application to fresh-cut pears might be a desirable strategy to alleviate discoloration, also considered to be an effective alternative to chemical coating.

Transcription factor PbNAC71 regulates xylem and vessel development to control plant height.

Dwarfism is an important agronomic trait in fruit breeding programs. However, the germplasm resources required to generate dwarf pear (Pyrus spp.) varieties are limited. Moreover, the mechanisms underlying dwarfism remain unclear. In this study, "Yunnan" quince (Cydonia oblonga Mill.) had a dwarfing effect on "Zaosu" pear. Additionally, the dwarfism-related NAC transcription factor gene PbNAC71 was isolated from pear trees comprising "Zaosu" (scion) grafted onto "Yunnan" quince (rootstock). Transgenic Nicotiana benthamiana and pear OHF-333 (Pyrus communis) plants overexpressing PbNAC71 exhibited dwarfism, with a substantially smaller xylem and vessel area relative to the wild-type controls. Yeast one-hybrid, dual-luciferase, chromatin immunoprecipitation-qPCR, and electrophoretic mobility shift assays indicated that PbNAC71 downregulates PbWalls are thin 1 expression by binding to NAC-binding elements in its promoter. Yeast two-hybrid assays showed that PbNAC71 interacts with the E3 ubiquitin ligase PbRING finger protein 217 (PbRNF217). Furthermore, PbRNF217 promotes the ubiquitin-mediated degradation of PbNAC71 by the 26S proteasome, thereby regulating plant height as well as xylem and vessel development. Our findings reveal a mechanism underlying pear dwarfism and expand our understanding of the molecular basis of dwarfism in woody plants.

A chromosome-scale assembly for 'd'Anjou' pear.

Cultivated pear consists of several Pyrus species with Pyrus communis (European pear) representing a large fraction of worldwide production. As a relatively recently domesticated crop and perennial tree, pear can benefit from genome-assisted breeding. Additionally, comparative genomics within Rosaceae promises greater understanding of evolution within this economically important family. Here, we generate a fully phased chromosome-scale genome assembly of P. communis 'd'Anjou.' Using PacBio HiFi and Dovetail Omni-C reads, the genome is resolved into the expected 17 chromosomes, with each haplotype totaling nearly 540 Megabases and a contig N50 of nearly 14 Mb. Both haplotypes are highly syntenic to each other and to the Malus domestica 'Honeycrisp' apple genome. Nearly 45,000 genes were annotated in each haplotype, over 90% of which have direct RNA-seq expression evidence. We detect signatures of the known whole-genome duplication shared between apple and pear, and we estimate 57% of d'Anjou genes are retained in duplicate derived from this event. This genome highlights the value of generating phased diploid assemblies for recovering the full allelic complement in highly heterozygous crop species.

PbRbohH/J mediates ROS generation to regulate the growth of pollen tube in pear

Respiratory burst oxidase homolog (Rboh) family genes play crucial functions in development and growth. However, comprehensive and systematic investigation of Rboh family members in Rosaceae and their specific functions during pear pollen development are still limited. In the study, 63 Rboh genes were identified from eight Rosaceae genomes (Malus domestica, Pyrus bretschneideri, Pyrus communis, Prunus persica, Rubus occidentalis, Fragaria vesca, Prunus mume and Prunus avium) and divided into seven main subfamilies (I-VII) according to phylogenetic and structural features. Different modes of gene duplication led to the expansion of Rboh family, with purifying selection playing a vital role in the evolution of Rboh genes. In addition, RNA sequencing and qRT-PCR results indicated that PbRbohH and PbRbohJ were specifically high-expressed in pear pollen. Subsequently, subcellular localization revealed that PbRbohH/J distributed at the plasma membrane. Furthermore, by pharmacological analysis and antisense oligodeoxynucleotide assay, PbRbohH/J were demonstrated to mediate the formation of reactive oxygen species (ROS) to manage pollen tube growth. In conclusion, our results provide useful insights into the functions, expression patterns, evolutionary history of the Rboh genes in pear and other Rosaceae species.

The overall effect of research years, rootstocks, and cultivars on the morphological attributes of pear trees

This research was conducted to determine the combined effect of 3 factors including rootstocks, cultivars, and research years on the morphological characteristics in Samsun/Türkiye ecological conditions in the research years of 2021 and 2022. Eight rootstocks consisting of quince BA29 (BA29), quince A (QA), FOX9, FOX11, OHxF333, OHxF87, FAROLD40, and European pear seedlings were used in the study, while the cultivars were 'Santa Maria', 'Williams', and 'Deveci'. The study results revealed the significance of the combined factors on all leaf characteristics of European pear. While rootstock diameter, scion diameter, tree length, and trunk cross-sectional area showed insignificant variations. It was determined that the canopy characteristics of ‘Williams' pear cultivar in combination with the FAROLD40 and OHxF333 in the research year 2022 were higher than other combinations, while the same combination was obtained with lower values in the case of other morphological characteristics. Generally, all the morphological attributes were obtained higher in the rootstocks and cultivars combination in the research year of 2022. In conclusion, the genetic capacity of rootstocks, cultivars, and variations of the climate situations in two consequent research years, resulted in variations in the morphological attributes of pear trees.

Allelic variation of BBX24 is a dominant determinant controlling red coloration and dwarfism in pear.

Variation in anthocyanin biosynthesis in pear fruit provides genetic germplasm resources for breeding, while dwarfing is an important agronomic trait, which is beneficial to reduce the management costs and allow for the implementation of high-density cultivation. Here, we combined bulked segregant analysis (BSA), quantitative trait loci (QTL), and structural variation (SV) analysis to identify a 14-bp deletion which caused a frame shift mutation and resulted in thepremature translation termination of a B-box (BBX) family of zinc transcription factor, PyBBX24, and its allelic variation termed PyBBX24ΔN14. PyBBX24ΔN14 overexpression promotes anthocyanin biosynthesis in pear, strawberry, Arabidopsis, tobacco, and tomato, while that of PyBBX24 did not. PyBBX24ΔN14 directly activates the transcription of PyUFGT and PyMYB10 through interaction with PyHY5. Moreover, stable overexpression of PyBBX24ΔN14 exhibits a dwarfing phenotype in Arabidopsis, tobacco, and tomato plants. PyBBX24ΔN14 can activate the expression of PyGA2ox8 via directly binding to its promoter, thereby deactivating bioactive GAsand reducing the plant height. However, the nuclear localization signal (NLS) and Valine-Proline (VP) motifs in the C-terminus of PyBBX24 reverse these effects. Interestingly, mutations leading to premature termination of PyBBX24 were also identified in red sports of un-related European pear varieties. We conclude that mutations in PyBBX24 gene link both an increase in pigmentation and a decrease in plantheight.

Ceratocystis fimbriata Causing Postharvest Fruit Rot of Pear in Punjab, Pakistan.

Pear (Pyrus communis) is an important deciduous fruit cultivated on a worldwide scale including Pakistan. During August 2021, a postharvest fruit rot disease was observed on several pears at various farmers market in Okara- a district of Punjab Province, Pakistan. The incidence of the disease varied from 7 to 20% with 35% disease severity. Necrotic spots (10 to 20 mm diameter) were first observed on the infected pear fruit. The spots enlarged gradually and developed into a brown, water-soaked and rotted lesion. Eventually, the whole fruit became soft, rotted and covered with a gray-brown mycelium. The isolates were obtained from the symptomatic tissues (n = 18) incubated on carrot discs that had been surface sterilized in 100-ppm streptomycin solution. After consistent sporulation of a fungus on the carrot discs, the ascospore masses formed at the tip of perithecia were transferred to malt extract agar (MEA). Primary conidia were cylindrical and hyaline (7 to 11 × 4 to 7 μm) and secondary conidia were hyaline and barrel-shaped (7 to 12 × 5 to 8 μm). Endoconidiophores with primary conidia were (12 to 27 × 2.6 to 5.5 μm). Perithecia produced on carrot discs were dark brown to black, and the base was 157 to 278 μm in diameter. Ascomatal necks were 512 to 656 µm long, dark brown to black, lighter in color at apices, tapering from base (23 to 45 μm diameter) to apex (13 to 24 μm diameter). Ostiolar hyphae were 41 to 79 μm long. Ascospores were hyaline, hat shaped, 3 to 4 μm long, and accumulated in a sticky matrix at the tips of perithecial necks. Mycelium was initially hyaline but became dark greenish brown after 7 days. Dark brown, thick-walled aleuroconidia (13 to 19.5 × 9 to 14 μm) appeared on culture plates after 2 months. Based on morphological characteristics, the fungus was identified as Ceratocystis fimbriata (Engelbrecht, 2005; Suwandi et al. 2021). To further confirm species identification, genomic DNA of two representative isolates (UO-05 and UO-06) was obtained using an extraction kit. The internal transcribed spacer (ITS) region was amplified using ITS1/4 (White et al. 1990). A BLAST search with GenBank accession nos. OR185451 and OR185456 indicated 99 to 100% identity with several C. fimbriata including type species (MH856050.1; KC493160.1; MT560374.1). Pathogenicity tests were conducted by inoculating nine disease-free pear (cv. Concord) fruit after disinfesting in 75% ethanol. A prepared spore suspension (1.0 × 106 spores/ml) was dropped on the wounds (a depth of 1 mm diameter) on the pear surface, which were made by a sterilized needle. 10 μl of a prepared spore suspension was dropped onto nine pears. Sterile water (10 μl) was dropped on the wounded sites of nine pear fruits as negative controls and all fruits were incubated in a growth chamber at 30/26°C (day/night, 90% relative humidity). Symptoms similar to those on the naturally infected fruits began after 4 to 5 days of inoculation, while controls remained healthy. The fungal isolates recovered from inoculated pears were morphologically identical to the C. fimbriata isolates originally recovered from symptomatic fruits fulfilling Koch's postulates. The pathogen has been reported to cause postharvest fruit rot of passion fruit and cucumber (Firmino et al. 2016; Li et al. 2019). To our knowledge, this is the first report of C. fimbriata causing fruit rot of pear in Punjab Province. The detection of this disease will help pear growers to take actions to monitor and prevent disease outbreak as well as develop an effective management practice when it occurs.

Genetic variations at BBX24 and MYB110a loci regulated anthocyanin accumulation in pear bud sports

Genetic variation contributes to the phenotypic diversity of plants. Most red pear cultivars that accumulate anthocyanins originated from somatic variation and are termed bud sports. ‘Hongzaosu’ is a bud sport derived from the green pear ‘Zaosu’. A new genetic map was constructed from a population derived from the cross of ‘Yuluxiang’ and ‘Hongzaosu’, from which PpBBX24 was identified as a crucial gene controlling anthocyanin accumulation. Genetic and phylogenetic evidence revealed that PpBBX24 is a repressor of anthocyanin biosynthesis in pear. A 14 bp deletion was detected in the third exon of PpBBX24 in ‘Hongzaosu’, resulting in premature termination of protein translation. The truncated PpBBX24 protein was a positive regulator of anthocyanin biosynthesis by activating the transcription of PpCHS and PpUFGT. Three independent variations in the BBX24 coding region that led to premature termination of translation were detected in other pear bud sports and the progeny of a bud sport that all accumulate anthocyanins. The genome of ‘Hongzaosu’ was assembled using both long-read and short-read sequences. By combining genomic and transcriptomic data, allele-specific expression of PpMYB110a was observed in the fruit skin of ‘Hongzaosu’, which was likely caused by large variation in the promoter. This work enhances understanding of coloration in red pears and provides a novel genomic resource for further studies on ‘Hongzaosu’ pear.

Evaluation of a push-and-pull strategy using volatiles of host and non-host plants for the management of pear psyllids in organic farming.

Pear decline (PD) is one of the most devastating diseases of Pyrus communis in Europe and North America. It is caused by the pathogen 'Candidatus Phytoplasma pyri' and transmitted by pear psyllids (Cacopsylla pyri, C. pyricola, and C. pyrisuga). Identifying attractant and repellent volatile organic compounds (VOCs) could improve the development of alternative plant protection measurements like push-pull or attract-and-kill strategies against pear psyllids. Our objective was to investigate which chemical cues of the host plant could influence the host-seeking behavior of pear psyllids, and if cedarwood (CWO) and cinnamon bark (CBO) essential oils could serve as repellents. Based on the literature, the five most abundant VOCs from pear plants elicited EAG responses in both C. pyri and C. pyrisuga psyllid species. In Y-olfactometer trials, single compounds were not attractive to C. pyri. However, the main compound mixture was attractive to C. pyri and C. pyrisuga females. CWO and CBO were repellent against C. pyri, and when formulated into nanofibers (NF), both were repellent in olfactometer trials. However, CBO nanoformulation was ineffective in masking the odors of pear plants. In a field trial, attractive, repellent CWO and blank formulated NF were inserted in attractive green sticky traps. C. pyri captures in traps with CWO NF were statistically lower than in traps with the attractive mixture. Nevertheless, no statistical differences in the numbers of caught specimens were observed between CWO NF and those captured in green traps baited with blank NF. Transparent traps captured fewer psyllids than green ones. In a second field study with a completed different design (push-and-count design), dispensers filled with CBO were distributed within the plantation, and attractive green sticky traps were placed around the plantation. The numbers of trapped pear psyllids increased significantly in the border of the treated plantation, showing that psyllids were repelled by the EOs in the plantation. Although further field evaluation is needed to assess and improve their effectiveness, our results show that these aromatic compounds, repellent or attractive both in nanoformulations and marking pen dispensers, offer great potential as an environmentally sustainable alternative to currently applied methods for managing pear decline vectors.

Understanding the Lost: Reconstruction of the Garden Design of Villa Peretti Montalto (Rome, Italy) for Urban Valorization.

Urbanization and urban regeneration can significantly impact cultural heritage, but a greater knowledge of the past natural and historical features is needed to value the past and understand the present. The lost Villa Peretti Montalto in Rome, once located in the area that corresponds to the current front side of Termini station, deserves great attention due to its cultural value. This work aimed to provide a floristic and functional reconstruction of the gardens of the villa during the XVI and XVII Centuries. From several bibliographic and iconographic sources, a critical analysis and interpretation of plant names was conducted. A list of 87 species and their location in the different garden sectors, during different periods with their specific uses, is provided. The arboreal design was made by classical species in the Roman context, like Cupressus sempervirens, Pinus pinea, Quercus ilex, and Ulmus glabra. In addition, ancient lost varieties of fruit trees (mainly Pyrus communis and Ficus carica) and several species of conservation interest were found. The knowledge of the ancient flora in historical gardens could be a key tool in urban greenery planning and touristic and cultural valorization.