Asian Pear Research Articles

Impact of Grinding Under Different Vacuum Levels on Browning, Antioxidant Activity, and Phenolic Compounds of Asian Pears (Pyrus pyrifolia Niitaka)

Impact of Grinding Under Different Vacuum Levels on Browning, Antioxidant Activity, and Phenolic Compounds of Asian Pears (Pyrus pyrifolia Niitaka)

Telomere-to-telomere Genome Assembly of two representative Asian and European pear cultivars

As the third most important temperate fruit, Pear (Pyrus spp.) exhibits a remarkable genetic diversity and is classified into two mainly categories known as Asian pear and European pear. Although several pear genomes are available, most of the released versions are fragmented and not chromosome-level high-quality. In this study, we report two high-quality genomes for Pyrus bretschneideri Rhed. cv. ‘Danshansuli’ (DS) and Pyrus communis L. cv. ‘Conference’ (KFL), which represent the predominant Asian and European cultivars, respectively, with nearly telomere-to-telomere (T2T) gap-free level. The finally assembled genome sizes for DS and KFL were 510.98 Mb and 510.71 Mb, respectively, with Contig N50 of 29.47 Mb and 30.47 Mb, where each chromosome was represented by a single contig. The DS and KFL genomes yielded a total of 46,394 and 44,702 protein-coding genes, respectively. Among these genes, the functional annotation accounted for 96.47% and 96.46% in the DS and KFL genomes. The two novels nearly T2T genomic information offers an invaluable resource for comparative genomics, genetic diversity analysis, molecular breeding strategies, and functional exploration.

Antioxidant Capacity and Bioactive Ingredients of Asian Pear

The combinations of soluble sugars, organic acids, and volatile organic compounds (VOCs) are crucial for how food is perceived and accepted. In order to evaluate the volatile organic compounds (VOCs) in Asian pears (Pyrus pyrifolia), headspace solid-phase microextraction (HS-SPME) was combined with gas chromatography-mass spectrometry (GC-MS) in this study. Among the 19 aroma compounds identified in the study conducted with a PDMS fiber, acetaldehyde and ethanol were found to be the most abundant. In addition, two more significant organic acids found in Asian pears were found to be malic acid (46.89 mg/100 g) and tartaric acid (45.08 mg/100 g). Glucose (84.70 mg/100 g) and sorbitol (65.75 mg/100 g) were identified in significant concentrations among the soluble sugars that directly affect fruit quality. LC-MS was used to investigate the phenolic content of Asian pears, and important phenolic compounds such as quinic acid (19227 g/L), chlorogenic acid (8445 g/L), procyanidin B2 (3146 g/L), liquiritin (435.1 g/L), and benzoic acid (363.1 g/L) were found.

High-Efficiency In Vitro Root Induction in Pear Microshoots (Pyrus spp.).

Extensive research has been conducted on the in vitro mass propagation of pear (Pyrus spp.) trees through vegetative propagation, demonstrating high efficiency in shoot multiplication across various pear species. However, the low in vitro rooting rates remain a significant barrier to the practical application and commercialization of mass propagation. This study aims to determine the favorable conditions for inducing root formation in the in vitro microshoots of Pyrus genotypes. The base of the microshoots was exposed to a high concentration (2 mg L-1) of auxins (a combination of IBA and NAA) for initial root induction at the moment when callus formation begins. The microshoots were then transferred to an R1 medium (1/2 MS with 30 g L-1 sucrose without PGRs) to promote root development. This method successfully induced rooting in three European pear varieties, one Asian pear variety, and a European-Asian hybrid, resulting in rooting rates of 66.7%, 87.2%, and 100% for the European pear (P. communis), 60% for the Asian pear (P. pyrifolia), and 83.3% for the hybrid pear (P. pyrifolia × P. communis) with an average of 25 days. In contrast, the control group (MS medium) exhibited rooting rates of 0-13.3% after 60 days of culture. These findings will enhance in vitro root induction for various pear varieties and support the mass propagation and acclimatization of pear. The in vitro root induction method developed in this study has the potential for global commercial application in pear cultivation.

Comparison of the blossom and shoot susceptibility of European and Asian pear cultivars to Pseudomonas syringae pv. syringae

Comparison of the blossom and shoot susceptibility of European and Asian pear cultivars to Pseudomonas syringae pv. syringae

Retrospective survey of Dickeya fangzhongdai using a novel validated real-time PCR assay.

Dickeya fangzhongdai, an aggressive plant pathogen, causes symptoms on a variety of crops and ornamental plants including bleeding canker of Asian pear trees. Historical findings stress the need for a specific detection tool for D. fangzhongdai to prevent overlooking the pathogen or assigning it to general Dickeya spp. Therefore, a qualitative real-time PCR for specific detection of D. fangzhongdai has been developed and validated. The developed assay shows selectivity of 100%, diagnostic sensitivity of 76% and limit of detection with 95% confidence interval in plant matrices ranging from 311 to 2,275 cells/mL of plant extracts. The assay was successfully used in a retrospective survey of selected host plants of relevance to Europe and environmental niches relevant to D. fangzhongdai. Samples of potato tubers and plants, plants from the Malinae subtribe (apple, pear, quince, and Asian pear tree) and fresh surface water from Slovenia were analyzed. D. fangzhongdai was not detected in any plant samples, however, 12% of surface water samples were found to be positive.

Machine Learning Evaluation of Fruit Ripeness with Multidimensional Sparse-Dataset Calibration

HighlightsThis article provides a machine-learning method for estimation of sugar content in target fruit using color appearance.Complex networks based on multidimensional datasets work effectively for color sensor calibration and data rebalancing.Beyond datapoint sparsity in datasets, estimation accuracy in sugar content is assured when an unsupervised-learning algorithm classifies the multidimensional datapoints composed of fruit color and relevant quantities.Abstract. In agriculture, harvests of fruits and vegetables depend on their ripeness, in which farmers should rely not only on the eye-sensed outlook but rigorously on constituents inside the targets, like sugar content. So far, detail measurements on the outlook color of fruits have been widely reported to detect suitable harvest times, where non-destructive instruments, which are costly in general agriculture fields, work well for color estimation whose resolution level is much higher than human eyes. In this study, we propose a scheme with a calibration procedure for sugar content prediction from outlook-color quantities, which is applicable even if a sensor includes systematic errors in output signals or the base dataset includes some datapoint sparsity. Most multidimensional data, which are both in agriculture and in other general cases, are imperfect in terms of several aspects, but they can be useful when we take appropriate sparsity detection and setting of rebalancing weights into account for machine learning procedures. We newly introduce a complex-network method for this purpose, and after the color calibration, we successfully obtain accurate hue and chroma, which are quantities representing a position on calibrated color coordinate, to predict °Brix sugar content in Japanese pears. Keywords: Asian pear, Color Elements, Fruit Ripening, °Brix Sugar Content, OHD.

Pointers on Harvesting Pears (Pyruscommunis L. and Pyruspyrifolia) in Moderate to Cold Climates

Pyruscommunis is a fruit that has its origins in China and Asia. It is a plant that is characterised by delicious, soft, fruits that are edible throughout the world. It is a known fact that this fruit grows well in temperate regions. In the USA, Pyruspyrifolia is another variety that's grown successfully. Some Asian pear varieties include Chinese Sand pear, Apple pear, Patharnakh and Gola pear, and these differ from each other in shape and colour. The purpose of this paper is to address pointers on harvesting Pyruscommunis L and P. pyrifolia in moderate to cold climates.

Exogenous application of oxalic acid improves the storage quality of Asian pears (Patharnakh) by regulating physiological and biochemical changes

Exogenous application of oxalic acid improves the storage quality of Asian pears (Patharnakh) by regulating physiological and biochemical changes

Influence of Different Packaging Material on Quality of Stored Asian Pear Fruit

Influence of Different Packaging Material on Quality of Stored Asian Pear Fruit

Genomic Data Analysis of the Nonpathogenic Erwinia amylovora Strain CP200242 Isolated from an Asian Pear Tree

Erwinia amylovora, the causative phytopathogen for fire blight, is a major threat to apple and pear. A nonpathogenic E. amylovora strain CP200242 was recently isolated from a pear orchard in South Korea. The nonpathogenicity of strain CP200242 was confirmed by inducing a hypersensitive reaction on tobacco leaves and by inoculating immature apple fruits and seedlings with bacterial suspensions. Herein, we report the complete genome sequencing of strain CP200242 data and provide some comparative genomic analysis against strain TS3128 and other closely related Erwinia species. Variant calling indicated that strain CP200242 had 29 variations in the annotated regions compared with strain TS3128, and six gene variants were related to pathogenesis. These genomic data provide valuable information on molecular differences between strains that may be useful for the control of the disease and enhance our understanding of the virulence factors in an E. amylovora reference genome. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Different Activities of Pectin-degrading Enzymes Affecting the Growth of Asian Pears

Different Activities of Pectin-degrading Enzymes Affecting the Growth of Asian Pears

First Report of Fire Blight on Chinese hawthorn (Crataegus pinnatifida Bunge) Caused by Erwinia amylovora in Korea.

Fire blight is one of the destructive plant diseases caused by Erwinia amylovora and causes enormous economic losses worldwide. Fire blight was initially reported in apples, pears, and Chinese quince (Park et al. 2016; Myung et al. 2016a, 2016b) in Korea, but recent studies have reported new hosts such as apricot (Lee et al. 2021) and mountain ash (Lim et al, 2023). These reports indicate that fire blight is likely to disperse to new hosts in Korea. During the nationwide survey in June 2021, we observed typical symptoms of blossom blight and shoot blight on a Chinese hawthorn (Crataegus pinnatifida Bunge) just near an orchard (37°09'21.7"N, 127°35'02.6"E) in Icheon, Gyeonggi Province, where fire blight of Asian pear occurred. For identifying its causal agent, bacterial isolates were recovered after incubating at 28 ℃ for 24 hours on tryptic soy agar (TSA) medium (BD Difco, USA) from blighted leaves and shoots that were surface sterilized with 70% alcohol for 30 sec and homogenized in 500 µl of 10mM MgCl2. Pure cultures of white to mucoid colonies were grown on mannitol glutamate yeast extract (MGY) medium, a semi-selective medium for E. amylovora (Shrestha et al, 2003). Two isolates produced 1.5 kb amplicon through colony PCR using amsB primers (Bereswill et al. 1995). Two strains (CPFB26 and CPFB27) from the Chinese hawthorn produced amplicons identical to that from the TS3128 strain of E. amylovora, isolated from the pear tree and identified in 2016 (Park et al. 2016). For the partial 16s rRNA sequences, the total DNA of these two strains was extracted using the Wizard DNA prep kit (Promega, USA), and PCR was performed using fD1 (5'-AGAGTTTGATCCTGGCTCAG-3') and Rp2 (5'-ACGGCTACCTTGTTACGACTT-3') primer sets and further sequenced (Weisburg et al. 1991). These sequences belonged to the E. amylovora clade and were identified as E. amylovora in phylogenetic analysis (GenBank accession no. OP753569 and OP753570). Based on BLASTN analysis, CPFB26 and CPFB27 showed 99.78% similarity to the sequences of the E. amylovora strains TS3128, CFBP 1430, and ATCC 49946. To confirm pathogenicity of the isolates, 10 ㎕ bacterial suspensions (1.5 ⅹ 108 CFU/ml) was injected through the veins of the upper 2nd leaf of 3-month-old clone of apple rootstock (Malus domestica cv. M29) and incubated for six days at 28 ℃ in a chamber with 12 hours of light per day. Petioles and stems turned red hue, and the shoots finally blighted. To complete Koch's postulates, colonies were recovered on TSA medium from the inoculated apple rootstocks and verified through colony PCR for the amsB and A/B primer set (Powney et al. 2011). Hawthorn has been reported as an epidemiologically important alternate host plant of fire blight (van der Zwet et al. 2012). This study is the first to report fire blight caused by E. amylovora in Chinese hawthorn in Korea. Because Chinese hawthorn is natively distributed in Korea and is widely used as a landscaping tree (Jang et al. 2006), the findings of this study suggest that early monitoring could prevent the spread of fire blight through natural hosts.

Heat Flux Analysis and Assessment of Drying Kinetics during Lyophilization of Fruits in a Pilot-Scale Freeze Dryer.

Vacuum freeze-drying as a process for achieving high product quality has attracted increasing attention in the last decade. Particularly in the pharmaceutical field and food processing industries, lyophilization can produce high-quality products compared to samples dried by conventional methods. Despite its benefits, lyophilization is a time-consuming and costly process that requires optimization of a number of process parameters, including shelf temperature, chamber pressure, freezing rate, and process time. This paper reports on the implementation of heat flux measurements that allow noninvasive real-time determination of the endpoint of the primary drying stage as an essential parameter for the effective optimization of the overall drying time. Quantitative analysis of the drying kinetics of five fruits (kiwifruit, avocado, Asian pear, persimmon, and passion fruit) was assessed by comparing the heat flux and temperature profiles of samples during the lyophilization process. For a 24 h lyophilization cycle, average heat fluxes in the primary drying phase ranged from 250 to 570 W/m2. A significant correlation was found between the temperature and heat flux distributions at the estimated endpoint of the sublimation process and the corresponding transition into the secondary drying stage. Furthermore, good agreement was also found for the freezing phase. The use of real-time heat flux measurements proved to be a cost-effective experimental method to better understand the process variables in order to reduce the lyophilization cycle time and overall energy consumption.

Effect of plastic film rain shelter installation in Asian pear orchards on frost and freeze damage and fruit quality

Effect of plastic film rain shelter installation in Asian pear orchards on frost and freeze damage and fruit quality

Effectiveness of Immature Asian Pear Extract on Pulmonary Injury Caused by Particulate Matter in Mice

The use of natural products in developing respiratory-function-protective pharmaceuticals is actively progressing. However, in this context, the improvement effects of young Asian pear (Pyrus pyrifolia Nakai) extracts have not been evaluated yet. Thus, this study investigated the anti-inflammatory and lung damage improvement effects of immature Asian pear extract (IAP; 400, 200, and 100 mg/kg) using a particulate matter 2.5 μm (PM2.5)-induced sub-acute lung injury mouse model. The experimental results were compared with dexamethasone (0.75 mg/kg), used as a control drug. After two intranasal instillations of PM2.5 and ten doses of IAP extract for eight days, changes in macroscopic lung autopsy, leukocyte fractionation from bronchoalveolar lavage fluid, lung antioxidant defense system, lung histopathology, and mRNA expression in lung tissue were confirmed. Stress-induced inflammatory lung damage through the increased expression of PM2.5-induced PI3K/Akt and p38 MAPK mRNA was significantly suppressed via the administration of IAP extract (400–100 mg/kg). Furthermore, IAP extract administration promoted serous fluid production in lung tissue, increased substance P and ACh levels, and decreased mucus-production-related expression of MUC5AC and MUC5B mRNA. Interestingly, the observed effects showed a dose-dependent manner without serious hepatotoxicity. The results of this study indicate that a proper oral administration of IAP extract could be helpful in protecting against lung diseases, positioning IAP extract as a potential candidate for an alternative agent to safeguard the respiratory system.

Detection of Internal Browning Disorder in ‘Greensis’ Pears Using a Portable Non-Destructive Instrument

Internal browning caused by prolonged cold storage poses a significant challenge to the visual appearance and flavor of Asian pears, which are economically valuable and a primary fruit exported from Korea. To address this issue, we established a cost-effective portable non-destructive piece of testing instrument using visible and near-infrared spectroscopy, focusing on the detection and discrimination of internal browning in ‘Greensis’ pears. Our investigation underscores the challenge of visually confirming browning, necessitating alternative methods for accurate assessment. Through comprehensive analysis involving three to four segments of 32 ‘Greensis’ pears, a robust calibration equation was derived. By employing partial least square regression on the absorption spectra within a 650–950 nm range, we developed a predictive model for detecting and quantifying browning. Through principal component analysis, normal pears were distinctly segregated from those exhibiting browning symptoms (discrimination accuracy of 95%). Furthermore, we established that pears with a browning index of 25 ± 2.0 are highly susceptible to browning following extended cold storage. Consequently, our proposed portable non-destructive instrument serves as a pivotal tool for farmers and fruit distributors, enabling efficient and precise selection of high-quality pears in an instance. Overall, our study introduces a practical solution to a pressing issue in the Asian pear industry.

Evaluation of Phenological and Morphological Properties of Some Asian Pear Varieties in the Climatic Conditions of South Moravia Therapeutic Interventions

The cultivation of Asian pear varieties in Czech climatic conditions, specifically South Moravian region, looks very promising. The introduction of new species and varieties can increase the biodiversity, what is an important factor in dealing with currentthreats in context with climatic changes. Asian pears are especially valuable due to their resistance to Erwinia amylovoraand Pear decline phytoplasma. They have also excellent tolerance to low temperatures and resistance to European pear scab (caused byVenturia pyrina). For this experiment, pomological and phenological properties were analysed on 32 pear varieties. The fruits were maturing from 9thof September (`Zao Su Li`) to the 20thof October (`Kieffer`). The heaviest fruits were determined at `Wu Jiu Xiang` (308 g on average). The lowest weight was detected at `Nanguo` (66 g on average). `Wu Jiu Xiang`, `Zao Su Li` and `Nanguo` have thin skin, which makes them ideal for direct consumption but also, they are prone to damage. `Baoshy` and `Dong guo` have thick skin, which provides good damage protection but decreases the organoleptic properties. The thick skin tends to be very bitter and overwhelms the taste of the fruit. The highest values of total soluble solids were measured in `Nanguo` (17.5%). The sourest was `Dong guo` (0.63 %) and `Nanguo` (0.54%of total titratable acids). Varieties of Asian pears and their fruits have very diverse characteristics and it is clear that their cultivation is worthwhile in the conditions of South Moravia (i.e. in the conditions of the Middle Europe).

Chilling-related browning of ‘Wonhwang’ pear cortex is associated with the alteration of minerals and metabolism

‘Wonhwang’ pear (Pyrus pyrifolia Nakai) is affected by a wide range of physiological disorders, especially internal browning (cortex browning) during long-term cold storage and subsequent shelf life. Postharvest fruit quality and metabolic changes of many Asian pears (P. pyrifolia) are well characterized, but little is known about the minerals and metabolites associated with internal browning induction and development in ‘Wonhwang’ pear during cold storage. The present study compares minerals and metabolites in cortex tissue of healthy fruit as well as symptomatic (browned) and sound tissues from fruit with internal browning that developed during long-term cold storage. P, K, Ca, sorbitol, shikimic acid, palmitic acid (C16:0), linoleic acid (C18:2), α-linolenic acid (C18:3), methionine, 1-hexenol, and (Z)-3-hexenal were lower in browned tissue than in healthy and sound tissues. In contrast, levels of glucose, fructose, fumaric acid, valine, leucine, isoleucine, lysine, phenolic compounds, lignoceric acid (C24:0), ethyl esters, and some volatile aldehydes were highest in browned tissue, compared with the other tissues. Many ethyl esters, aromatic amino acids, branched-chain amino acids, phenolic compounds, soluble solids content, fructose, and glucose were associated with internal browning. Furthermore, “tryptophan metabolism”, “arginine biosynthesis”, “alanine, aspartate, and glutamate metabolism”, “α-linolenic acid metabolism”, and “glycine, serine, and threonine metabolism” were the processes most impacted by internal browning. Overall, the largest metabolic differences appeared between damaged and asymptomatic cortex as several metabolic processes were influenced by internal browning.

Characteristics and Control of Pear Scab (Venturia nashicola): A Review

Pear scab, caused by <i>Venturia nashicola</i>, is one of the most devastating diseases of Asian pears in Korea, Japan, China, and Taiwan. To manage this disease, growers mainly relied on chemical control. However, continuous use of chemical causes not only environmental contaminant but also the emergence of resistance to pathogens, so a more sustainable management plan is needed. Therefore, it is necessary to understand the life cycle and infection characteristics of <i>V. nashicola</i> and to set an active control strategy according to meteorological conditions rather than, as in the past, calendar-based control or continuous use of a specific fungicide system. Various results of the related research results were reviewed to summarize the race, infection characteristics, and control system of <i>V. nashicola</i>, a pear scab, and to discuss plans for a more effective control system.