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Glycine-aspartic acid-serine-leucine (GDSL) type lipases/esterases genes play critical roles in plant development and are related to the responses to abiotic and biotic stress. However, little is known about the GDSL family in pear (Pyrus spp.). Studies have shown GDSL-domain proteins play key roles in suberin deposition. Suberin deposition in the fruit epidermis, also called russeting, is an important defect that negatively affects consumer appeal in some fruit species, such as pear, apple and grapevine. Fruit russeting is mainly associated with cuticle microcracking and suberin accumulation in the inner part of the epidermal cell walls. To gain insight into the role of the GDSL gene family in suberin deposition and russet development in pear, we performed a genome-wide characterization of the GDSL family, including their identification, chromosomal localization, phylogenetic relationships, and expression patterns, in different tissues/organs in pear. One hundred and thirteen GDSL-type lipases/esterases genes were identified in the pear genome, and a phylogenetic analysis revealed that GDSL family can be classified into four distinct groups. Thirty GDSL genes were co-expressed with five homolog pear genes of three well-known suberin biosynthesis Arabidopsis genes (AtGPAT5, AtASFT, and AtCYP86B1) in the transcriptional co-expression network during pear fruit development. Among the 30 co-expressed GDSL genes, twelve genes were further analyzed by quantitative Real-time PCR, and the results showed the expression levels of the 12 genes were different between the russet exocarp and green exocarp of sand pear at different fruit development stages. Our study provides a detailed overview of the GDSL gene family and lays the foundation for future functional characterization of GDSL genes in P. bretschneideri.

Nonhost resistance is the outcome of most plant/pathogen interactions, but it has rarely been described in Rosaceous fruit species. Apple (Malus x domesticaBorkh.) have a nonhost resistance toVenturia pyrina, the scab species attacking European pear (Pyrus communisL.). Reciprocally,P. communishave a nonhost resistance toVenturia inaequalis, the scab species attacking apple. The major objective of our study was to compare the scab nonhost resistance in apple and in European pear, at the phenotypic and transcriptomic levels. Macro- and microscopic observations after reciprocal scab inoculations indicated that, after a similar germination step, nonhost apple/V. pyrinainteraction remained nearly symptomless, whereas more hypersensitive reactions were observed during nonhost pear/V. inaequalisinteraction. Comparative transcriptomic analyses of apple and pear nonhost interactions withV. pyrinaandV. inaequalis, respectively, revealed differences. Very few differentially expressed genes were detected during apple/V. pyrinainteraction, preventing the inferring of underlying molecular mechanisms. On the contrary, numerous genes were differentially expressed during pear/V. inaequalisinteraction, allowing a deep deciphering. Pre-invasive defense, such as stomatal closure, could be inferred, as well as several post-invasive defense mechanisms (apoplastic reactive oxygen species accumulation, phytoalexin production and alterations of the epidermis composition). In addition, a comparative analysis between pear scab host and nonhost interactions indicated that, although specificities were observed, two major defense lines seems to be shared in these resistances: cell wall and cuticle potential modifications and phenylpropanoid pathway induction. This first deciphering of the molecular mechanisms underlying a nonhost scab resistance in pear offers new possibilities for the genetic engineering of sustainable scab resistance in this species. Concerning nonhost scab resistance in apple, further analyses must be considered with the aid of tools adapted to this resistance with very few cells engaged.

The resistant phenotype of pear cultivars includes either complete resistance or tolerance to the attack by the causative agent of fire blight. The effect of ferritin and active iron (Fe2+) concentrations was compared in resistant (Dargazi), tolerant (Harrow Sweet), and susceptible (Bartlett) pear cultivars inoculated with a wild type strain of Erwinia amylovora (Ea273). The examination of necrosis revealed that resistance to the disease manifested itself as a delay in the appearance of symptoms and progression of the disease. Despite a rise in ferritin levels in all cultivars following disease agent inoculation, resistant and tolerant cultivars showed greater ferritin levels than susceptible cultivar. In addition, only resistant and tolerant cultivars displayed a drop in Fe2+ levels. The rate of decrease in Fe2+ content in Dargazi and Harrow sweet cultivars was 28 and 33%, respectively. Hydrogen peroxide (H2O2) and hydroxyl radical (OH•−) accumulation and intensities were considerably distinctive. Furthermore, tolerant and sensitive cultivars started producing OH•− radicals faster than resistant cultivar. According to these findings, different pathways are employed by pear cultivars to respond to the causative agent of fire blight.

Introduction: Opuntia ficus-indica is a well adapted cactus to extreme climatic environments. In the usual diet and food industry, it is an interesting source of food ingredients. In general, the protective role of prickly pears has been due to their antioxidant components, phenolic compounds, and some minor components present in the content of seed oil and seed protein and the oil from cactus pear seed has been found with high levels of unsaturated fatty acids ,with antioxidant and antimicrobial activity as well as cardioprotective, antithrombotic, anti-inflammatory, antiarrhythmic, hypolipidemic, and antihyperglycemic effect. Aim: To evaluate the in vitro antimicrobial activity of Opuntia ficus-indica seed oil against Streptococcus mutans. Materials and Methods: Broth microdilution assay was performed by following modifications: Brain heart infusion (BHI) broth was prepared and sterilise at 121c for 15lbs, the 100 microlitre of streptococcus mutans inoculated at freshly prepared broth and incubated at 37c for 24 hours. Then BHI broth prepared with sucrose and serial two fold dilution were done with 160microlitre broth and 40 microlitre prickly pear seed oil. Then 20 microlitre of culture was added. Column 11 contains BHI using sterile micro pipettes and the plates were incubated at 30 c for 18 hours. The growth of bacteria was visualised and lowest concentration with no visible growth was recorded as MIC. Results: This study results shows that, by broth microdilution method at concentration ranging from 10%-0.039% v/v, Opuntia ficus-indica seed oil potentially inhibits the growth of streptococcus mutans at the concentration of 0.03% (v/v). Conclusion: From the study, the results demonstrated that Opuntia ficus-indica seed oil shows noticeable antimicrobial activity against streptococcus mutans. Use of essential oils against oral pathogens can be an alternative to other antimicrobial agents which could be cheap and effective modules used in control of bacteria which are responsible for oral infections.

Food security is threatened in Southern Africa, because of unpredictable droughts and higher summer temperatures brought on by climate change and global warming. Durable and hardy plants that grow easily and quickly in such conditions must be adopted to ensure sustainable and reliable food supplies. The young cladodes (nopalitos) from the cactus pear plant, which adapts to hot and dry climates, is an underutilised alternative food source that can serve as a healthy vegetable. It thrives in many environments such as deserts, below sea level, high altitude regions and tropical regions with temperatures above 50°C. Nopalitos are a traditional staple vegetable and have been consumed in Mexico for over 9000 years. However, it is underutilised and unknown as an alternative vegetable in Africa. Research on the physiochemical and nutritional content has been conducted. However, the information on harvesting nopalitos from cultivars available in South Africa for optimal edible quality is not available. Good quality nopalitos are young, thin, bright green, soft, fresh and not too sour or slimy. This paper aims to identify the effect of and the interaction between size, cultivar and harvesting season to obtain optimal eating quality. Data were obtained for two cultivars (Morado and Fusicaulis) at 9 cm, 12 cm, 15 cm, 18 cm, 21 cm and 24 cm, which were harvested in spring (October) and autumn (March) over two years. The quality characteristics were translated into the measurable attributes of morphology (weight, width, diameter, volume and surface area), texture (firmness and compressibility), colour (L*, a*, b*, C*and h°), turgidity (moisture content, mucilage yield and viscosity) and gustatory (percentage titratable acidity, pH and total soluble solids). ANOVA and Principal Component Analyses were performed to determine significant differences and interactions between the length groups, two cultivars and two seasons. The results showed that the size, cultivar and season influenced the edible characteristics. Both cultivars were most tender at 15 cm and presented the best edible qualities in spring. Morado showed better colour, turgidity and gustatory qualities. Morado was thinner, a brighter green colour, less sour and less slimy compared to Fusicaulis nopalitos.

Pears are one of the oldest and the third most important fruit species grown in temperate regions. They are consumed because of their nutritional and health benefits, in fresh form or as various processed products. This article resolves the etiology of the Penicillium-like mold symptoms on pear fruits in Serbia. Samples of pear fruits with blue mold and other Penicillium-like mold symptoms were collected in Serbia from 2016 to 2019, from four storages. The recovered isolates were identified and characterized according to a polyphasic approach. Morphological and physiological analyses were performed on three media and five temperatures, respectively. Four loci (internal transcribed spacer, beta-tubulin, calmodulin, and DNA-dependent RNA polymerase II second largest subunit) were used for sequencing, genetic identification, and phylogenetic analyses. The results of the identification by conventional and molecular methods were in agreement, and they revealed that the obtained isolates belong to five species: Penicillium crustosum, P. expansum, P. italicum, Talaromyces minioluteus, and T. rugulosus. In a pathogenicity test, P. crustosum, P. expansum, T. minioluteus, and T. rugulosus produced decay on artificially inoculated pear fruits, and P. italicum induced tissue response lesions. The results of this study are the first reports of T. minioluteus and T. rugulosus as postharvest pear pathogens. Also, these are the first world records of T. minioluteus, T. rugulosus, and P. italicum on fruits of European pear. Furthermore, this is the first finding of P. crustosum, P. expansum, P. italicum, T. minioluteus, and T. rugulosus on pear fruit in Serbia.

In addition to their use in traditional medicine, cactus pear (Opuntia species) are a source of vegetal nutrients in many countries. The aims of this study were to determine variability in the nutritional value of 42 spineless cactus pear cultivars, identify correlations between nutritional traits, and determine superior cultivars based on cladode nutritional value. Cladodes of 42 spineless cactus pear cultivars grown under the same glasshouse conditions were collected from the Roodeplaat research farm of the Agricultural Research Council, South Africa. The sliced, dried and powdered cladodes were subjected to quantitative analysis of their vitamin C, β-carotene and mineral element contents. Significant variations in nutritional values were observed among the different cultivars. Vitamin C content ranged from 8.95 mg/100 g in cultivar Ofer to 124 mg/100 g in cultivar Malta, whilst β-carotene content ranged from 3.9 mg/100 g in cultivar Murado to 31.4 mg/100 g in cultivar Cross X. Potassium and calcium were the most abundant mineral elements present, whilst iron was found to be the least present among the mineral elements quantified. A significant positive association was established between calcium (Ca), potassium (K) and zinc (Zn) contents. A direct selection for increased concentration of Ca could be a selection criterion for the development of population with an indirect improvement of K and Zn concentrations. The observed variations highlight the need for a careful cultivar selection for population and product development using spineless cactus pear cladodes.

Recently, Cadophoraluteo-olivacea has been reported as a post-harvest pathogen of side rot of apple (Malusdomestica) in Latvia, and of pear (Pyruscommunis) in Italy and the Netherlands. In 2018 and 2019, in South Tyrol (northern Italy) 11 fungal cultures, identified as C.luteo-olivacea based on ITS (internal transcribed spacer region) sequence data, were obtained from apple fruit displaying post-harvest side rot symptoms. The fruit were sampled in packinghouses representing different apple growing areas of South Tyrol. For a more accurate taxonomic assignment, two additional molecular genetic loci, β-tubulin (TUB2) and translation elongation factor 1α (TEF-1α), of seven isolates were amplified and sequenced. Phylogenetic analysis based on multi-locus DNA sequence data confirmed that isolates from apple fruit with side rot symptoms indeed represented C.luteo-olivacea. A pathogenicity test performed on apple fruit of ‘Golden Delicious’ confirmed the virulence of a representative isolate. So far, C.luteo-olivacea represents a minor post-harvest pathogen of apple but considering the losses that this fungus can cause to other crops, the awareness about this potential apple disease should be raised.

Background. Natural populations of fruit and small fruit plants in Belarus and their specific and varietal composition for a long time attracted the attention of pomologists and breeders. Identification and mobilization of unique local forms and landraces as genetic sources of useful traits as well as monitoring duplicate collections will contribute to their more effective use in breeding practice to develop competitive domestic cultivars of various crops and reveal the adaptability of foreign cultivars to the conditions of Belarus.Methods. The itinerary of the collecting mission passed through 6 regions of the Republic of Belarus (Gomel, Minsk, Mogilev, Vitebsk, Brest, and Grodno) in 2012–2017.Results. As a result, 221 samples of fruit, small fruit and nut plants were collected, including 18 rootstocks of fruit crops. By 2021, 105 unique landraces were tested in the plant introduction and quarantine nursery and planted in the field gene bank, including 28 accessions of apple, 33 of pear, 11 of sour cherry, 5 of sweet cherry, 9 of plum, 8 of apricot, 1 of almond, 2 of hazel, 3 of garden strawberry, 1 of black chokeberry, 1 of viburnum, and 1 of bird cherry. There are plans to use the obtained accessions in breeding practice assources of valuable agronomic traits (high winter hardiness, high yield, resistance to a set of plant pathogens, etc.).

Erwinia amylovora is a plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. This bacterium colonizes host vascular tissues via the production of exopolysaccharides (EPSs) including amylovoran. It is well-established that the nearly ubiquitous plasmid pEA29 of E. amylovora is an essential virulence factor, but the underlying mechanism remains uncharacterized. Here, we demonstrated that pEA29 was required for E. amylovora to produce amylovoran and to form a biofilm, and this regulation was dependent on the thiamine biosynthesis operon thiOSGF. We then conducted carbohydrate and genetic analyses demonstrating that the thiamine-mediated effect on amylovoran production was indirect, as cells lacking thiOSGF produced an EPS that did not contain glucuronic acid, one of the key components of amylovoran, whereas the transcriptional activity and RNA levels of the amylovoran biosynthesis genes were not altered. Alternatively, addition of exogenous thiamine restored amylovoran production in the pEA29-cured strain of E. amylovora and positively impacted amylovoran production in a dose-dependent manner. Individual deletion of several chromosomal thiamine biosynthesis genes also affected amylovoran production, implying that a complete thiamine biosynthesis pathway is required for the thiamine-mediated effect on amylovoran production in E. amylovora. Finally, we determined that an imbalanced tricarboxylic acid cycle negatively affected amylovoran production, which was restored by addition of exogenous thiamine or overexpression of the thiOSGF operon. In summary, our report revealed a novel signaling pathway that impacts E. amylovora virulence in which thiamine biosynthesis enhances bacterial respiration that provides energetic requirements for the biosynthesis of EPS amylovoran. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

The diseases presence in various species of fruits are the crucial parameter of economic composition and degradation of the cultivation industry around the world. The proposed pear fruit disease identification neural network (PFDINN) frame-work to identify three types of pear diseases was presented in this work. The major phases of the presented frame-work were as the following: (1) the infected area in the pear fruit was detected by using the algorithm of K-means clustering. (2) hybrid statistical features were computed over the segmented pear image and combined to form one descriptor. (3) Feed forward neural network (FFNN), which depends on three learning algorithms of back propagation (BP) training, namely Scaled conjugate gradient (SCG-BP), Resilient (R-BP) and Bayesian regularization (BR-BP), was used in the identification process. Pear fruit was taken as the experiment case during this work with three classifications of diseases, namely fire blight, pear scab, and sooty blotch, as compared to healthy pears. PFDINN framework was trained and tested using 2D pear fruit images collected from the Fruit Crops Diseases Database (FCDD). The presented framework achieved 94.6%, 97.3%, and 96.3% efficiency for SCG-BP, R-BP, and BR-BP, respectively. An accuracy value of 100% was achieved when the R-BP learning algorithm was trained for identification.

The article outlines the ways for the development of horticulture in the Republic of Kazakhstan, provides data on the study of apple, pear, cherry and plum rootstocks. The results of many years of research in order to optimize scion-rootstock combinations suitable for setting up intensive plantings are analyzed. The original plants isolated as a result of such observations should be propagated without disturbing productivity and genetic stability, and mother planting and field repositories should be established with the resulting planting material of the highest quality categories. To obtain basic seedlings, it is necessary, first of all, to use seedlings of the Sievers apple tree (Malus siversi) and the Niedzwetzky apple tree (Malus niedzwetzkyana), growing in the forests of the northern Tien Shan, and for the pear, seedlings of low-growing rootstocks of the East Asian group: Xiang Li, Tszy Li, Yue li, Bai li, Chang bai li, because the seeds of pome crops are free from harmful viruses. Before harvesting stone fruit seeds, it is necessary to test trees, since a harmful viral infection is transmitted with pollen.

Anthocyanins are common secondary metabolites in plants that impart red coloration to fruits and flowers. The important WRKY transcription factor family plays multifaceted roles in plant growth and development. In this study, we found a WRKY family gene, Pyrus bretschneideri WRKY75, that may be involved in anthocyanin synthesis in pear. Unlike Arabidopsis thaliana WRKY75, PbWRKY75 may be a positive regulator of anthocyanin synthesis. A transient expression assay indicated that PbWRKY75 promoted pear anthocyanin synthesis. The structural genes (PbANS, PbDFR, and PbUFGT) and positive regulators (PbMYB10 and PbMYB10b) of anthocyanin synthesis were significantly upregulated in the fruitlet skins of PbWRKY75-overexpressing "Zaosu" pears. Subsequently, yeast one-hybrid and dual-luciferase assays indicated that PbWRKY75 promoted PbDFR, PbUFGT, and PbMYB10b expression by activating their promoters. These results revealed that PbWRKY75 may promote the expression of both PbMYB10b and anthocyanin late biosynthetic genes (PbDFR and PbUFGT) by activating their promoters, thereby inducing anthocyanin synthesis in pear. This study enhanced our understanding of the mechanism of pear anthocyanin synthesis, which will be beneficial in the improvement of pear peel color.

The current social demand for organic, sustainable, and eco-friendly approaches for farming, while ensuring the health and productivity of crops is increasing rapidly. Biocontrol agents are applied to crops to ensure biological control of plant pathogens. Research on the biological control of white root rot disease caused by a soil-borne pathogen, Rosellinia necatrix, is limited in pears compared to that in apple and avocado. This pathogenic fungus has an extensive host range, and symptoms of this disease include rotting of roots, yellowing and falling of leaves, wilting, and finally tree death. The severity of the disease caused by R. necatrix , makes it the most harmful fungal pathogen infecting the economical fruit tree species, such as pears, and is one of the main limiting factors in pear farming, with devastating effects on plant health and yield. In addition to agronomic and cultural practices, growers use chemical treatments to control the disease. However, rising public concern about environmental pollution and harmful effects of chemicals in humans and animals has facilitated the search for novel and environmentally friendly disease control methods. This review will briefly summarize the current status of biocontrol agents, ecofriendly methods, and possible approaches to control disease in pear orchards.

Pear (Pyrus bretschneideri), one of the most widely planted fruit trees in the world, is infected by pear ring rot disease, which is triggered by Botryosphaeria dothidea. Previous research has shown that exogenous calcium enhanced pear resistance to B. dothidea. To explore the molecular mechanism of calcium in pear pathogen resistance, we searched the differentially expressed genes (DEGs) between calcium and H2O treatment with B. dothidea inoculation in pear by using RNA-seq data. On the basis of the standard of a proportion of calcium/H2O fold change >2, and the false discovery rate (FDR) 2O and calcium treatments under B. dothidea inoculation at 2 days postinoculation (dpi) (D2) and 8 dpi (D8), respectively, indicating that significantly more genes in D2 responded to calcium treatment. Results of the gene annotation showed that DEGs were focused on plant−pathogen interactions, hormone signal transduction, and phenylpropanoid biosynthesis in D2. Moreover, transient silencing of PbrCML30 (pear calmodulin-like proteins 30), which had significantly higher expression in response to calcium than H2O treatments, conferred compromised resistance to B. dothidea. Exogenous calcium treatment slightly alleviated the symptoms of TRV2-PbrCML30 leaves compared with TRV2 leaves under inoculation, supporting its key role in pear resistance to B. dothidea. Overall, the information obtained in this study provides a possible mechanism of calcium in regulating pear resistance to B. dothidea.

Salicylic acid (SA) plays a pivotal role in delaying fruit ripening and senescence. However, little is known about its underlying mechanism of action. In this study, RNA sequencing was conducted to analyze and compare the transcriptome profiles of SA-treated and control pear fruits. We found a total of 159 and 419 genes differentially expressed between the SA-treated and control pear fruits after 12 and 24 h of treatment, respectively. Among these differentially expressed genes (DEGs), 125 genes were continuously differentially expressed at both treatment times, and they were identified as candidate genes that might be associated with SA-regulated fruit ripening and senescence. Bioinformatics analysis results showed that 125 DEGs were mainly associated with plant hormone biosynthesis and metabolism, cell wall metabolism and modification, antioxidant systems, and senescence-associated transcription factors. Additionally, the expression of several candidate DEGs in ripening and senescent pear fruits after SA treatments were further validated by quantitative real-time PCR (qRT-PCR). This study provides valuable information and enhances the understanding of the comprehensive mechanisms of SA-meditated pear fruit ripening and senescence.

In a recent survey of post-harvest rot pathogens in European pear in Southern Oregon, Alternaria spp. were frequently isolated from orchard samples of pear flowers and fruits. Morphological differences were observed within the isolated cultures. A preliminary NCBI BLAST search analysis using sequences of the ATPase locus across 94 isolates of Alternaria spp. obtained from pear fruit rots revealed three major Alternaria sections: sect. Alternata, sect. Infectoriae, and sect. Ulocladioides. Thirteen isolates were selected based on their genetic and morphological diversity across three Alternaria sections and were subjected to multilocus phylogenetic analysis using sequences from plasma membrane ATPase, calmodulin, and Alt a1 loci. Within sect. Alternata, four Alternaria arborescens isolates and one A. destruens isolate were identified; within sections Infectoriae and Ulocladioides, one A. rosae isolate and two A. botrytis isolates were identified, respectively. The remaining five isolates could not be identified based on the available sequences for the three loci used in this study. In addition to the phylogenetic analysis, pathogenicity assays revealed differential responses to these isolates on four pear cultivars: Anjou, Bartlett, Comice, and Bosc. Inoculation of isolates within Alternaria sect. Alternata resulted in fruit lesions across all cultivars, with Bosc pear being significantly susceptible (P < 0.0001). Isolates within Alternaria sect. Ulocladioides caused rots on Anjou and Bosc pears, while isolates within Alternaria sect. Infectoriae developed rots on Bosc pear only. This study suggests that there is differential susceptibility of pear cultivars to Alternaria rots, and the severity of post-harvest rot depends on the type of Alternaria spp. and cultivar predominant in a region.

The Multidrug and Toxic Compound Extrusion (MATE) protein belongs to a secondary transporter gene family, which plays a primary role in transporting many kinds of substrates such as organic compounds, secondary metabolites, and phytohormones. MATE protein members exist in both prokaryotes and eukaryotes. However, evolution and comprehensive analysis of the MATE genes has not been performed in Rosaceae species. In the present study, a total of 404 MATEs genes were identified from six Rosaceae genomes (Prunus avium, Pyrus bretschneideri, Prunus persica, Fragaria vesca, Prunus mume, and Malus domestica) and classified into eight main subfamilies (I-VII) based on structural and phylogenetic analysis. Microcollinearity analysis showed that whole-genome duplication events might play a vital role in the expansion of the MATE genes family. The Ka/Ks analysis, chromosomal localization, subcellular localization, and molecular characteristics (length, weight, and pI) were performed using various bioinformatics tools. Furthermore, different subfamilies have different introns-exons structures, cis-acting elements, and conserved motifs analysis, indicating functional divergence in the MATE family. Subsequently, RNA-seq analysis and real-time qRT-PCR were conducted during Chinese pear fruit development. Moreover, PbMATE genes were significantly expressed under hormonal treatments of MeJA (methyl jasmonate), SA (salicylic acid), and ABA (abscisic acid). Overall, our results provide helpful insights into the functions, expansion complexity, and evolutions of the MATE genes in Chinese pear and five Rosaceae species.

Fire blight, caused by the bacterial phytopathogen Erwinia amylovora, is an economically important and mechanistically complex disease that affects apple and pear production in most geographic production hubs worldwide. We compile, assess, and present a genetic outlook on the progression of an E. amylovora infection in the host. We discuss the key aspects of type III secretion–mediated infection and systemic movement, biofilm formation in xylem, and pathogen dispersal via ooze droplets, a concentrated suspension of bacteria and exopolysaccharide components. We present an overall outlook on the genetic elements contributing to E. amylovora pathogenesis, including an exploration of the impact of floral microbiomes on E. amylovora colonization, and summarize the current knowledge of host responses to an incursion and how this response stimulates further infection and systemic spread. We hope to facilitate the identification of new, unexplored areas of research in this pathosystem that can help identify evolutionarily susceptible genetic targets to ultimately aid in the design of sustainable strategies for fire blight disease mitigation.

Aspergillus spp produced laccases and xylanases when grown on a solid-state culture on prickly pear peels. Peels were sun-dried, or dried in an oven at different temperatures. The drying rate, the coloration of the dried material, and the degradation susceptibility depended on the drying mode and on temperature. Drying rate was slower for sun-dried peels, and increased at higher temperatures on oven-dried peels. Sun-dried peels were brown, while oven-dried peels were greenish. Fungal cultures grew faster on sun-dried peels and reached highest enzymatic activities earlier. Oven drying caused hornification of peels, delaying both fungal growth and enzyme production. In our study laccases titers were higher than in previous studies using various agricultural residues. Prickly pear peels are a convenient substrate to produce a lignocelulolytic extract that can be used in several bioprocesses.

Anthocyanins are important components in the peel of red pears and contribute to the appearance of the fruit. Melatonin application is known to affect anthocyanin biosynthesis, but the effect of preharvest melatonin application on fruit coloration remains largely unknown. The objective of this study was to determine the effects of preharvest melatonin application on pigmentation, phenolic compounds, and the expression of related genes in Nanhong pear (Pyrus ussuriensis). The applications were performed during the pre-color-change period by spraying 50 or 200 µmol L−1 of melatonin on fruits. We found that treatment with melatonin had a significant effect on color development. The concentrations of anthocyanins and flavonols were enhanced by melatonin treatment, whereas hydroxycinnamate and flavanol concentrations were reduced. Quantitative real-time PCR analyses indicated that the transcription levels for most anthocyanin biosynthetic genes and anthocyanin-related transcription factors were induced by melatonin. Melatonin application also stimulated the expression of melatonin biosynthesis-related genes and consequently caused an increase in endogenous melatonin concentration. These results provide insights into melatonin-induced fruit coloration and will facilitate the application of exogenous melatonin in agriculture.

This study was carried out at Sedyghazi private orchard located in Abu Ghaleb road at 164 kilometer from Cairo to Alex desert road, Giza, governorate Egypt during two seasons (2019 and 2020) on thirteen - year - old Le-Conte pear trees budded on Pyrus communis rootstock, planted at 3.5 × 4 meters apart grown in sandy soil under drip irrigation system (EC= 3.40 dS m−1). . The experiment was arranged in a spilt plot design, the main plots were represented by four levels of foliar application of Amphora coffeaeformis algae extract (AC1= 0, AC2= 250, AC3= 500 and AC4= 1000 ppm) and the sub plot were split by Natural Elements Mixture included three levels (NEM1= 0, NEM2 = 2.0 and NEM3 =4.0 kg/tree /year). Data revealed that, NEM2 (2.0 kg/tree/year) gave more or less similar values as those of level NEM3 (4.0 kg/tree/year) especially for yield, TSS, TSS/acid ratio, total sugars, N, K, Fe, zn and Mn leaf content. Meanwhile, yield, fruit chemical properties, macro & micronutrients and proline content were significantly increased gradually by increasing algae extract level up to 500 ppm. In the most cases the difference between AC (500 and 1000 ppm) was insignificant. Concerning the interaction, treatments (NEM2x AC3), (NEM2x AC4), (NEM3x AC3) and (NEM3x AC4) gave more stimulating effects on most characters. So, treatments (NEM2x AC3) or (NEM2x AC4) were sufficient for helping to alleviate salinity stress and gave the highest values of yield, fruit quality and nutritional status.

Many tropical fruit trees flower profusely. Majority produce many fruits at the onset. Most of these fruits if not all, may be aborted. African pear is a typical example. In this research, four fruit abortion-prevention treatments were evaluated namely: Distilled water, Urea, Giberellin and Coconut water. Floral and pomological parameters were compared and averaged over a period of three consecutive years. At fruit maturity, number of fruits/inflorescence/branches was counted and compared to test the effects of the various treatments on fruit retention and enhancing its pomological characteristics. The design was Randomized complete block design. Regression and correlation in Statgraphic 16.0 software package were used to compare the effects of the various treatments on flowering, fruiting and fruit retention. Application of growth regulators significantly enhanced flowering, fruiting and fruit set. The best fruit retention of 76.56 % was obtained by Coconut water which was however, not significantly (P=0.05) different from 72.75% fruit set obtained by Giberellin. Distilled water gave the lowest fruit-set of 21.41 % which was however significantly (P=0.05) different from 66.48% obtained by Urea. There was no significant difference (P=0.05) in some of the pomological attributes measured. Application of Giberellin and Coconut water significantly (P=0.05) enhanced flowering, fruiting and fruitset in African pear.

This paper presents the results on the breeding work carried out by the Subtropical Scientific Centre of the Russian Academy of Sciences. Currently, the Centre's breeders are doing a lot of work aimed at breeding new fine yielding cultivars of subtropical and flower crops that will be resistant to growing conditions; they include kaki persimmon, feijoa, mandarin, freesia, crown anemone, pelargonium and chrysanthemum. The sources of high-level priority traits in flower crops that are valuable for further breeding in order to improve decorative (colour, flower shape, inflorescence), economic and biological traits (flowering period, a large number of flowers in the inflorescence, storage period of cut flowers, disease resistance, high reproduction coefficient) were recorded. The aim of the research is to improve the subtropical and flower crops assortment. The objects of the research were 989 hybrid forms: 136 citrus crops, 56 persimmon, 36 feijoa, 38 tea plant, 11 pear, 24 hazel, 108 freesia, 398 crown anemone, 120 pelargonium and 62 chrysanthemum hybrids. New cultivars with a complex of valuable traits have been created as a result of the scientific work. Over the past five years, FRC SSC of RAS has created 50 new cultivars: 26 pelargonium, 15 anemone, 5 freesia, 2 chrysanthemum, 1 persimmon and 1 apple and submitted them to the State Cultivar Commission. The "State Register of Selection Achievements Authorized for Use for Production Purposes" has included 63 cultivars developed by FRC SSC RAS, including 26 pelargonium, 13 anemone, 9 chrysanthemum, 7 freesia, 4 hazel, 3 feijoa and 1 tea plant cultivars. 46 patents for breeding achievements have been obtained.Представлены результаты селекционной работы ФИЦ «Субтропический научный центр Российской академии наук» (ФИЦ СНЦ РАН). Селекционерами ФИЦ СНЦ РАН проводится большая работа, направленная на выведение новых урожайных, высококачественных, устойчивых к биотическим и абиотическим факторам сортов субтропических и цветочных культур: хурмы восточной, фейхоа, мандарина, фрезии, анемоны корончатой, пеларгонии и хризантемы. Выделены источники хозяйственно ценных признаков цветочных культур, которые представляют интерес для селекции на улучшение декоративных (окраска, форма цветка, соцветия) и хозяйственно-биологических признаков (период цветения, большое количество цветков в соцветии, период стояния в срезе, устойчивость к болезням, высокий коэффициент размножения). Цель исследований – совершенствование сортимента субтропических и цветочных культур. Объектами исследований служили 989 гибридных форм, из них цитрусовых – 136, хурмы – 56, фейхоа – 36, чая – 38, груши – 11, лещины – 24, фрезии – 108, анемоны корончатой – 398, пеларгонии – 120, хризантемы – 62. Результатом работы стало выведение сортов с комплексом ценных признаков. За последние пять лет в ФИЦ СНЦ РАН создано и передано в Госсорткомиссию РФ 50 новых сортов, в том числе 26 – пеларгонии, 15 – анемоны, 5 – фрезии, 2 – хризантемы, 1 – хурмы и 1 – яблони. В «Государственный реестр селекционных достижений…» включено 63 сорта селекции ФИЦ СНЦ РАН, в том числе 26 сортов пеларгонии, 13 – анемоны, 9 – хризантемы, 7 – фрезии, 4 – фундука, 3 – фейхоа, 1 – чайного растения. Получено 46 патентов на селекционные достижения.

Background The development of ecofriendly tools against plant diseases is an important issue in crop protection. Screening and selection process of bacterial strains antagonists of 2 pathogenic bacterial species that limit very important crops, Erwinia amylovora, the causal agent of the fire blight disease, and Pectobacterium carotovorum, the causal agent of bacterial potato soft rot, were reported. Bacterial colonies were isolated from different ecological niches, where both pathogens were found: rhizosphere of potato tubers and fruits and leaves of pear trees from the northwest region of Algeria. Direct and indirect confrontation tests against strains of E. amylovora and P. carotovorum were performed. Results Results showed a significant antagonistic activity against both phytopathogenic species, using direct confrontation method and supernatants of cultures (pS. plymuthica had a better inhibitory effect than the strains of P. fluorescens against both pathogens. In vivo results on immature pear fruits showed a significant decrease in the progression of the fire blight symptoms, with a variation in the infection index from one antagonistic strain to another between 31.3 and 50%, and slice of potato showed total inhibition of the pathogen (P. carotovorum) by the antagonistic strains of Serratia plymuthica (p Conclusion This study highlighted that the effective bacteria did not show any infection signs towards plant tissue, and considered as a potential strategy to limit the fire blight and soft rot diseases.

Monilinia fructicola has been widely reported as the causal agent of brown rot disease on many Rosaceae family fruits worldwide. It has been reported on stone fruits, e.g., peach, plum, cherry, apricot and mume; as well as pome fruits, e.g., apple, pear and hawthorn. Loquat is a member of the Eriobotrya genus in subfamily Maloideae along with apple, pear and hawthorn. So far, loquat has not been reported as the host of any Monilia species. In June 2019, brown rot symptoms were observed on loquat fruits in an orchard in Wuhan, Hubei Province, China. Thirty single spore isolates were obtained and identified as M. fructicola based on morphological characteristics and molecular analysis. This is the first report of loquat brown rot disease caused by Monilia species in the world. Furthermore, upon artificial inoculation, all three Monilia species from peach in China, i.e., M. fructicola, M. mumecola and M. yunnanensis, could cause typical brown rot disease on loquat fruits. At the same time, M. fructicola isolates from loquat showed virulence similar to those isolates from peach when the pathogenicity test was conducted on peach fruits. These results suggested that loquat could be infected by other Monilia species and that isolates from loquat also have potential to damage other Rosaceae family fruits in practice.

Absract Morocco has started promoting the use of biomass to replace fractions of industrial materials. One of the main constituents of biomass is polysaccharides. Cellulose is the main constituent of the cell wall of the plant, representing about 50% of the biomass. The cactus is one of the plants rich in cellulose and polysaccharides, this plant is composed the 100% of the parietal polysaccharides, these components have a beneficial interest in several areas because of their degree of polymerization microfibrils and their mechanical properties, especially in the medical field. The cactus is among the plants that have the ability to survive on their reserves during a period of temporary drought through a water storage system, unlike similar plants. Cladodes and prickly pear skin of the species Opuntia Megacantha are precursors very rich in cellulosic, pectic and hemicellulosic materials (Habibi et al, 2003; Malainine et al., 2003a ), there is limited so far in the feed, the agri-food, pharmaceutical and cosmetics industry, especially the promotion of young cladodes. Our goal is to study the chemical activation of the two precursors, cladodes and peel, for the prep of the adsorbent and specific surfaces range from 450 m2/g to 1000 m2/g, then treatment of textile liquid discharges, this work is the continuity of the results of an article on the prep of activated carbon based on cellulosic cactus waste.

Expanding the assortment through the development of new highly adaptable cultivars is the main task of pear breeding in the Middle Urals. The most significant agronomic traits are winter hardiness, high fruit yield, and good fruit quality. The zoned pear assortment for the Middle Urals includes six cultivars. Six more cultivars now undergo the State Variety Trials. One of them is the new pear cultivar ‘Tais’ (breeding number DL-33-104), the result of crossing Dyuymovochka × Zhanna d’Ark. Cv. ‘Tais’ has been in variety studies at Sverdlovsk Horticultural Breeding Station (Yekaterinburg) since 2006. The new cultivar is characterized by good winter hardiness and productivity. The average yield at the age of 10–14 years is 9.42 tons per hectare, while the maximum yield is 19.81 t/ha. Fruits are yellow, with a good sweet taste, weighing 94 g. The content of dry matter is 11.9%, sugars 9.0%, and titratable acids 0.4%. According to the results of long-term research, the new pear cultivar ‘Tais’ was submitted to the State Variety Trials in 2017.

Mealybugs are agricultural pests occurring all over the world. The Sao Francisco Valley is one of the most productive regions regarding the cultivation of fruit crops in Brazil, demanding a proper phytosanitary management that can be obtained through the biological control of pests. Fortnight samples of mealybugs associated with roots, trunk, leaves and fruits of grapevines, pear, apple, persimmon, guava and Barbados cherry were performed in commercial farms in the sub-medium Sao Franciso Valley, Brazil, during twelve months. In order to identify mealybugs based on morphological characteristics from adult female specimens, samples were stored in Eppendorf tubes containing ethanol 70%, labeled and then identified. A total of 10,189 mealybugs, including nymphs and adult females were collected, with the highest number of specimens found in grapevines. The second most affected crop was persimmon, followed by pear. The lowest infestation was observed in guava, apple and Barbados cherry. Pseudococcidae evidenced preference for fruits. The following mealybugs were observed in the sub-medium region of the Sao Francisco Valley: Planococcus sp., Planococcus citri, Phenacoccus solenopsis, Dysmicoccus brevipes, Maconellicoccus hirsutus, Ferrisia virgata and Pseudococcus elisae. Made available in DSpace on 2022-10-21T14:09:14Z (GMT). No. of bitstreams: 1 Mealybugs-on-fruit-crops-in-the-Sao-Franciso-Valley-2021.pdf: 406403 bytes, checksum: 63dd9e1ae8377c4a52b1fca53ddbdcd3 (MD5) Previous issue date: 2021

Pear cultivation accounts for a large proportion of worldwide orchards, but its sustainability is controversial because it relies on intensive use of pesticides. It is therefore crucial and timely to find alternative methods to chemical control in pear orchards. The psyllids Cacopsylla pyri and Cacopsylla pyricola are the most important pests of pear trees in Europe and North America, respectively, because they infest all commercial varieties, causing damage directly through sap consumption or indirectly through the spread of diseases. A set of natural enemies exists, ranging from generalist predators to specialist parasitoids. Trechnites insidiosus (Crawford) is undoubtedly the most abundant specialist parasitoid of psyllids. In our literature review, we highlight the potential of this encyrtid species as a biological control agent of psyllid pests by first reviewing its biology and ecology, and then considering its potential at regulating psyllids. We show that the parasitoid can express fairly high parasitism rates in orchards, and almost perfectly matches the phenology of its host and is present early in the host infestation season, which is an advantage for controlling immature stages of psyllids. We propose new research directions and innovative approaches that would improve the use of T. insidiosus in integrated pest management strategies in the future, regarding both augmentative and conservation biocontrol. We conclude that T. insidiosus has many advantages and should be included as part of integrated biological control strategies of pear psyllids, along with predators, in-field habitat conservation, and the rational use of compatible chemicals. © 2021 Society of Chemical Industry.

This study aimed to determine the size and shape of experimental plots that provide maximum precision using relative information method. This trial was conducted at the Federal Institute of Bahia. Plant height, cladode length, cladode width, cladode thickness, cladode area, cladode area index, number of cladodes, cladode total area and yield were measured in the third production cycle, 930 days after planting. The plants, defined as basic units, were arranged in 39 plot sizes so that the crop would fill the whole experimental area. Then, plot shapes with higher relative information and equal plot size in basic units were selected. The experimental plot with eight basic units in size ensures higher efficiency in the experimental evaluation. This combination between size and shape, besides meeting all evaluation requirements of the characteristics normally assessed in studies with forage cactus pear, has the maximum control of soil heterogeneity, thereby decreasing experimental error and significantly increasing precision.

Fire blight is a devastating disease of apple, pear and quince caused by the Gram-negative bacterium Erwinia amylovora. As antibiotics are not allowed against fire blight in Switzerland, optimization of alternative plant protection strategies is required. In this context, fire blight tolerant cultivars become of higher importance to control the disease. A plant protection product efficacy trial against fire blight with the susceptible cultivar ‘Gala Galaxy’ and the tolerant cultivar ‘Ladina’ bred at Agroscope was set up at the Agroscope Steinobstzentrum Breitenhof in 2018. Four different treatment strategies, including an untreated control, were tested on both cultivars after inoculation with Erwinia amylovora. ‘Ladina’ showed less fire blight blossom cluster infection in untreated and treated plants compared to ‘Gala Galaxy’. Blossom cluster infection rates following different plant protection treatments did not differ significantly from each other in ‘Gala Galaxy’ whereas they did in ‘Ladina’.

Halyomorpha halys, (the brown marmorated stink bug, BMSB), is a high-concern invasive species causing severe damage to orchards in many countries outside its native Asian range. Control options matching both effectiveness and sustainability are currently lacking. Inhibitors of chitin biosynthesis might be exploited for integrated management programs because of the overall better ecotoxicological profile in comparison with most neurotoxic insecticides used so far against BMSB. In this study, the activity of triflumuron, a benzoylphenyl urea hampering chitin biosynthesis, was tested on BMSB in laboratory and field conditions. In laboratory bioassays, the insecticide was sprayed on potted peach plants (30 cm high) and residues were aged in a glasshouse for 0, 7, 14, and 21 d. Then, third-instar bugs were placed on the plants and continuously exposed to residues. Mortality was scored after 7, 14, and 21 d exposure. Triflumuron caused significantly higher mortality on BMSB nymphs in comparison with water controls at all aging periods. Moreover, aging of residues up to 21 d did not cause any significant reduction of activity. Field experiments were also carried out in 2019 in eight pear orchards. Injuries to fruits at harvest were compared between plots where triflumuron was added to insecticide sprays against BMSB and control plots managed exactly in the same way but without any triflumuron treatment. An overall mean of 9.99 ± 1.98% stink bug injured fruits was detected in plots managed with the strategy including triflumuron, whereas 19.45 ± 3.55% of fruits were injured in plots assigned to controls.

The GRAS protein family encodes a family of plant-specific transcription factors that have diverse and significant functions in regulating plant development and anthocyanin biosynthesis. Our study ...

Blackhead caused by Alternaria alternata is a fatal necrotrophic fungal that affects Korla fragrant pear. To date, little is known at the molecular level about the defense response of pear to blackhead disease and the pathogenic mechanism of A. alternata infection. To investigate the specific host-pathogen interaction between A. alternata and pear, we examined the accumulation of host-responsive mRNAs using RNA-seq technology. A total of 25,877 differentially expressed genes (DEGs) were identified. Further analysis revealed that the DEGs mainly participate in plant cell wall integrity, plant hormone pathways, plant-pathogen interactions and the defense response (transcription factors, defense-related proteins). Most of the DEGs involved in the plant hormone, PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI) pathways, as well as defense-related proteins, were significantly up-regulated. In addition, DEGs encoding enzymes involved in cutin and wax synthesis and most transcription factors are significantly down-regulated. Based on these results, we speculate that these pathways play important roles in the response of pear to A. alternata. This study has presented new insights into the molecular mechanisms that regulate the response of pear fruits to A. alternata infection. © 2021 Friends Science Publishers

Pollination is an essential process for plants to carry on their generation. Pollination is carried out in various ways depending on the type of plant species. Among them, pollination by insect pollinator accounts for the most common. However, these pollinators have be decreasing in population density due to environmental factors. Therefore, use of artificial pollination is increasing. However, there is a lack of information on microorganisms present in the artificial pollens. We showed the composition of bacteria structure present in the artificial pollens of apple, kiwifruit, peach and pear, and contamination of high-risk pathogens was investigated. Acidovorax spp., Pantoea spp., Erwinia spp., Pseudomonas spp., and Xanthomonas spp., which are classified as potential high-risk pathogens, have been identified in imported pollens. This study presented the pollen-associated bacterial community structure, and the results are expected to be foundation for strengthening biosecurity in orchard industry.

Scab caused by Venturia nashicola is one of the most serious diseases of Asian pears, including Japanese pear (Pyrus pyrifolia var. culta) and Chinese pears (P. bretschneideri and P. ussuriensis). Breeding scab-resistant pear cultivars is essential to minimize fungicide use and development of fungicide resistance. A survey of pathogenic specialization in V. nashicola is needed to ensure durable scab resistance in cultivated pears. V. nashicola race 1, 2, and 3 isolates, each differing in pathogenicity to Japanese pear cultivar Kousui and Asian pear strain Mamenashi 12, have been reported in Japan. In this study, isolates collected from scabbed pears in China and Taiwan were classified as V. nashicola based on conidial size and mating ability. However, various isolates had pathogenicity distinct from races 1, 2, and 3 according to tests on seven differential host genotypes of pear cultivars from Japan (Kousui and strain Mamenashi 12), China (Jingbaili, Yali, Linyuli, and Nanguoli), and Taiwan (Hengshanli). These new races were designated as races 4 to 7. Progenies characteristic of race 3 isolates were produced using a cross between race 1 and race 2 isolates, suggesting the possible role of sexual recombination in the emergence of novel races. Japanese pear cultivar Kinchaku and Chinese P. sinkiangensis ‘Xiangli’ (a Korla fragrant pear grown in China) did not show visible symptoms after inoculation with any of the seven races. Broad scab resistance in Kinchaku and Xiangli makes them a promising genetic resource for resistance breeding programs.

Background Parthenocarpy results in traits attractive to both consumers and breeders, and it overcomes the obstacle of self-incompatibility in the fruit set of horticultural crops, including pear (Pyrus bretshneider). However, there is limited knowledge regarding the genetic and molecular mechanisms that regulate parthenogenesis. Results Here, in a transcriptional comparison between pollination-dependent fruit and GA4-induced parthenocarpy, PbCYP78A6 was identified and proposed as a candidate gene involved in parthenocarpy. PbCYP78A6 is similar to Arabidopsis thaliana CYP78A6 and highly expressed in pear hypanthia. The increased PbCYP78A6 expression, as assessed by RT-qPCR, was induced by pollination and GA4 exposure. The ectopic overexpression of PbCYP78A6 contributed to parthenocarpic fruit production in tomato. The PbCYP78A6 expression coincided with fertilized and parthenocarpic fruitlets development and the expression of fruit development-related genes as assessed by cytological observations and RT-qPCR, respectively. PbCYP78A6 RNA interference and overexpression in pear calli revealed that the gene is an upstream regulator of specific fruit development-related genes in pear. Conclusions Our findings indicate that PbCYP78A6 plays a critical role in fruit formation and provide insights into controlling parthenocarpy.

It damages the apple tree, sweet cherry, peach, plum, cherry plum, pear and almond. Hibernates in the egg phase on the bark of shoots and branches, in forks. Hatching of larvae is observed at the end of the blooming of the apple tree. The released larvae feed on budding buds, young leaves. Then go to the shoots, branches. Similar transitions are observed in protononym and deutonymph, which turns into an adult. The development of the tick from larva to adult female is 30 days.

William Bartlett (Pyrus communis) pears were diced, packaged and subjected to a short continuous microwave treatment (4.7 min) which increased the temperature from 19.92 ± 1.36 to 101.11 ± 2.50 °C. Retorted samples were processed at 95.40 °C for 18.0 min for comparison. Recorded temperature data were used to calculate C, D and F values. Brix, pH, colour, texture, microbial counts, microstructure and volatile profiles of both treated samples were analysed immediately after process and after 1, 2, 4 and 6 weeks of storage at 4 °C. The C, D and F values of microwaved pears were significantly (p < 0.05) lower compared to those of retorted samples. Both methods of processing resulted in products with standard plate count of < 10 cfu/g during 6 weeks of storage at 4 °C. Microwave processing offered a final product with a total colour difference in the same range as the retorted samples. Polyphenol oxidase enzyme was inactivated below the detection level by both microwave processing and retorting. Microwaved samples also maintained cell wall integrity, although the intercellular intactness was slightly weakened and prevented the final product from developing water-soaked appearance. During storage, volatile profiles of microwaved samples showed significant (p < 0.05) differences, whereas the retort samples showed minimal changes. In comparison to conventional retorting, a short microwave treatment can result in a superior quality end-product with a comparable microbiological quality and a minimum shelf life of 6 weeks at 4 °C.

‘Gold Rush’ pear (Pyrus communis L.) is a russet-coloured fruit with soft buttery textured flesh and is gaining wide popularity in Australia and other countries along with other pear cultivars. The fruit are sensitive to ethylene, and exposure even at very low concentrations significantly reduces the storage duration as well as fruit quality during storage. The efficacy of two new ethylene antagonist compounds, namely, 1H-cyclopropabenzene (BC) and 1H-cyclopropa[b]naphthalene (NC), as well as 1-methylcyclopropene (1-MCP) in regulating ethylene production, respiration rates and maintaining the fruit quality of ‘Gold Rush' pear during 150 d and 200 d of controlled atmosphere (CA) storage (2.3 ± 0.5% O2 and 0.4 ± 0.15% CO2 and 0.50 ± 0.71 °C) was investigated. The pear fruit was fumigated with 1 µM BC (0.09 µL L−1) or 1 µM NC (0.14 µL L−1) or 18 µM 1-MCP (1 µL L−1) for 18 h at room temperature and the untreated fruit was considered as the control. Following 150 d and 200 d CA storage, the fruit fumigated with BC and NC exhibited significantly reduced ethylene and respiratory climacteric peak rates and they were lowest in the fruit treated with 1-MCP. The pear fruit fumigated with ethylene antagonists (BC, NC and 1-MCP) exhibited lower physiological loss of weight (PLW) (up to 2.06 times) and higher fruit firmness (up to 1.07 times) throughout the CA storage period, compared to the control fruit. The fruit fumigated with BC and NC had lower levels of SSC, glucose and sorbitol compared to other treatments. There was no significant effect of ethylene antagonist treatments on levels of individual organic acids, total phenols, ascorbic acid and total antioxidant capacity of the fruit pulp. Therefore, new ethylene antagonist compounds, BC and NC, exhibit the potential to act as ethylene antagonists in long-term CA-stored ‘Gold Rush’ pears to retard the fruit ripening process, extend storage life and maintain the fruit quality. The effectiveness of the different concentrations of BC and NC in suppressing ethylene production in different cultivars of pears warrants further investigation.

En México existen escasos estudios que describen a los cuerpos acuáticos empleados para la agricultura y el rol que tiene el agua de riego como fuente de inóculo, persistencia y dispersión de parásitos fitopatógenos, tal es el caso de los oomycetes que habitan ambientes acuáticos con capacidad de infectar un amplio rango de hospedantes cultivados. Debido a la falta de información sobre qué géneros y especies de oomycetes están presentes en el agua, su identificación es de suma importancia para gestionar alternativas de manejo y control de estos para la producción agrícola en la región. Con el objetivo de determinar qué oomycetes se aíslan en aguas superficiales empleadas para la irrigación en el Valle de Culiacán, Sinaloa, en el periodo comprendido de septiembre de 2018 a enero de 2019, en diferentes redes hídricas agrícolas (presas, estanques, ríos y canales), se colocaron trampas flotantes elaboradas con bolsas de polipropileno y dos frutos de pera que sirvieron como cebo. Se obtuvieron aislados de oomycetes, los cuales se identificaron en base a sus características morfológicas y secuencias de ADN (con los iniciadores ITS 4/6, COX y NADH), también se realizaron pruebas de patogenicidad en plantas y frutos de las familias de solanáceas y cucurbitáceas. Se aislaron e identificaron los organismos: Phytophthora parsiana, P. virginiana, P. lagoariana, P. capsici y P. hydropathica. Todas las especies de Phytophthora resultaron patogénicas, tuvieron capacidad de infectar plantas y frutos, causando síntomas de marchitez y pudrición en las hortalizas inoculadas.

Background The plant U-box (PUB) proteins are a family of ubiquitin ligases (E3) enzymes that involved in diverse biological processes, as well as in responses to plant stress response. However, the characteristics and functional divergence of the PUB gene family have not yet been previously studied in the Chinese white pear (Pyrus bretschneideri). Results In the present study, we identified 62 PbrPUBs in Chinese white pear genome. Based on the phylogenetic relationship, 62 PUB genes were clustered into five groups. The results of conserved motif and gene structure analysis supported the classification phylogenetic tree. The PbrPUB genes were unevenly distribution on 17 pear chromosomes, chromosome 15 housed most member of PUB family, with eight PUB genes. Cis-acting element analysis indicated that PUB genes might participate in diverse biological processes, especially in the response to abiotic stresses. Based on RNA-data from ‘Dangshansuli’ at seven tissues, we found that PUB genes exhibited diverse of expression level in seven tissues, and qRT-PCR experiment further supported the reliable of RNA-Seq data. To identify candidate genes associated with resistance, we conducted qRT-PCR experiment the expression level of pear seed plant under four abiotic stresses, including: ABA, dehydration, salt and cold treatment. One candidate PUB gene associated with dehydration stress was selected to conduct further functional experiment. Subcellular localization revealed PbrPUB18 protein was located on cell nucleus. Furthermore, heterologous over-expression of PbrPUB18 in Arabidopsis indicated that the over-expression of PbrPUB18 could enhance resistance in drought treatment. In conclusions, we systematically identified the PUB genes in pear, and provided useful knowledge for functional identification of PUB genes in pear.