In this study, the effects of different Xinjiang pear varieties and ‘Korla Fragrant Pear’ pollination on the stone cells and lignin of fruit were investigated. The contents of stone cells and lignin, ...and the activities of related enzymes polyphenol oxidase (PPO), peroxidase (POD), and phenylalanine ammonium lyase (PAL) were analyzed in fruit from different pollination combinations at different growth and developmental stages. Results showed that the stone cell mass density decreased rapidly at 60 to 90 days and 90 to 120 days after flowering. The stone cell and lignin contents, and activities of the three enzymes (PPO, POD, and PAL) decreased rapidly at 60 days after flowering. The stone cell mass density, stone cell and lignin contents, and enzyme activity of fruit from different pollination combinations varied at different timescales. The pear variety ‘Bayue‘ had the lowest stone cell and lignin contents in mature fruit from different pollination combinations. The stone cell content correlated positively with lignin content, stone cell mass density, and enzyme activity.
The development of calyxes in ‘Korla’ fragrant pear is influenced by hormones. This study was conducted to investigate the effects of different plant growth regulators on the endogenous hormone ...content of young ‘Korla’ fragrant pear fruit. The hormone contents indoleacetic acid (IAA), gibberellin acid (GA 3 ), and abscisic acid (ABA) of young ‘Korla’ pear fruits treated with water, IAA, and triiodobenzoic acid (TIBA) were determined by high-performance liquid chromatography, and the relationship between the content and ratio of endogenous hormones and calyx abscission in ‘Korla’ fragrant pear was explored. The results showed that the rate of calyx abscission in the ‘Korla’ pear fruits treated with TIBA was significantly higher than that of fruits treated with water and IAA, and that of fruits treated with water was significantly higher than that of fruits treated with IAA. The GA 3 content was higher than the IAA and ABA contents during each period. The IAA content of the stalk was higher than that of the calyx tube and flesh. The GA 3 and ABA contents of the calyx tube were higher than those of the stalk and flesh. The IAA and GA 3 contents of the first order were higher than those of the fourth order. The ABA content of the fourth-order fruit was higher than that of the first order. The (IAA+GA 3 )/ABA in the calyx tube was significantly higher than that in the flesh and fruit stalk. After IAA treatment, the IAA, GA 3 , and ABA contents of the first-order calyx tube increased by 47.7%, 17%, and 31.6%, respectively, whereas those of the fourth-order calyx tube increased by 65.3%, 39.9%, and 33.2%, respectively. After TIBA treatment, the IAA, GA 3 , and ABA contents of the first-order calyx tube increased by 46.1%, 36.5%, and 50.0%, respectively, the IAA content of the fourth-order tube decreased by 25.5%, and the GA 3 and ABA contents increased by 22.0% and 12.2%, respectively. The IAA, GA 3 , and ABA contents of the flesh and fruit stalk did not significantly differ from those in the calyx tube. The results indicated that spraying IAA during flowering promoted calyx persistence, whereas spraying TIBA promoted calyx abscission. These findings provide certain theoretical references and practical criteria for improving the quality of ‘Korla’ fragrant pear.
•Meyerozyma guilliermondii controlled blue mold of pears.•M. guilliermondii rapidly colonized the wounds and surfaces of pears.•M. guilliermondii enhanced the defense-related enzyme ...activities.•Defense-related proteins in pears were upregulated.
This study assessed the biocontrol efficacy of Meyerozyma guilliermondii against blue mold decay caused by Penicillium expansum in pears and the possible mechanisms involved. The results indicated that M. guilliermondii significantly inhibited the blue mold decay caused by P. expansum without affecting the quality of the pears. M. guilliermondii rapidly colonized the wounds and surfaces of the pears at both 4°C and 20°C. The rapid growth in the population of M. guilliermondii in the wounds and surface environments of pears indicated that it has the potential to inhibit pathogens in pears. The activities of antioxidant enzymes (peroxidase and catalase) in the pear were improved after the application of the yeast. Phenylalanine ammonialyase (PAL), a key enzyme involved in lignin biosynthesis and defense related activity, was also markedly enhanced. Generally, the application of yeast induced disease resistance in the pear. The results pear proteomics profile after M. guilliermondii treatment showed that 17 proteins were significantly up-regulated and 13 were down-regulated in response to induction with M. guilliermondii. Most of the proteins were involved in defense and stress responses based on biological process. These results provided a new insight into the biocontrol mechanism of the antagonist yeast in the pear fruit.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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•10 % CO2 maintained energy charge and content of ATP and ADP of fresh-cut pear.•10 % CO2 promoted the coding gene expression and activity of CCO, SDH ATPase.•10 % CO2 maintained ...content of NADPH and NADP in response to adversity.•10 % CO2 promoted activity of NADK, G-6-PDH and 6-PGDH generating NADPH and NADP.
Controlled atmosphere (CA) package serves as a nascent research tool in post-harvest, while validation of high levels of CO2 is plausible owing to the deficiency of biological understanding. Hence, the effect of 10 % CO2 on the respiration pathway and energy metabolism of fresh-cut pears was investigated in this study. During 5 days of storage, total respiratory rate was moderated with maintained mitochondrial membrane integrity and slowly increasing membrane permeability under 10 % CO2. Under 10 % CO2 CA package, the energy charge was 1.6 times than that of control. Enzymes involving in energy metabolism were induced or inhibited in activity and expression level. Comprehensively considering the changes among enzymes and genes, the preservative effects of high level of CO2 CA package on fresh-cut pear fruit could be divided into three aspects: inhibition of senescence, decrease of energy status and promotion of stress resistance. This work revealed the undergoing biochemical mechanism of how fresh-cut pear act in response to high CO2 CA package, from the perspective of respiration pathway and energy metabolism.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Conducted Monte Carlo simulation on planar and spherical geometric models.•Integrated phase-measuring profilometry with spatial frequency domain imaging.•Proposed and validated correction method for ...diffuse reflectance.•Applied the proposed correction method to the bruise detection of pears.
Curved surface of fruit has a great influence on the measurement of absorption (μa) and reduced scattering coefficients (μ’s) by using the spatial frequency domain imaging (SFDI) technique. In this study, a developed SFDI system was used to conduct phase-measuring profilometry (PMP) to obtain the surface height of tested object. Monte Carlo (MC) simulation was conducted on planar and spherical geometric models, and the correction formula for diffuse reflectance (Rd) was then determined by simulation results and validated by tilt standard reflector. The Rd correction effect on estimating μa and μ’s was revealed by five semi-spherical phantoms, which turned out that both the accuracy and uniformity were substantially improved, with the relative error range of 0.78 %-11.84 % and 2.83 %-8.95 %, and standard deviation range of 1.89 × 10−5 mm-1-1.42 × 10-3 mm-1 and 1.76 × 10-4 mm-1-8.17 × 10-3 mm-1 for corrected μa and μ’s respectively. Finally, the proposed Rd correction method was applied to the bruise detection in pears, the comparisons of μa and μ’s maps between normal and bruised pears were conducted. The results revealed that the area around the highest point of normal pear contour was easily to be identified as bruised area before Rd correction; the μa and μ’s maps for normal pear were more uniform, and for bruised pears after the correction, and the injured area was highlighted for bruised pears. The profile correction method proposed in this study, coupled with the SFDI technique, was essential for precise measurement of μa and μ’s of pear tissues, resulting in less misclassification for bruise detection of pears.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The European pear psylla, Cacopsylla pyri L. (Hemiptera: Psyllidae), is one of the most serious arthropod pests of pear. Since proper control of this pest is essential, better understanding of the ...complex plant–pest relationship is mandatory. This research deals with constitutive polyphenolic profiles in leaves of 22 pear cultivars of diverse origin (P. communis, P. pyrifolia, and P. pyrifolia × P. communis) and different resistance to psylla. The study was designed to show which differences in the polyphenolic profile of leaves from resistant and susceptible pear cultivars could be utilized as information in subsequent breeding programs. The results demonstrated that the leaves of Oriental pear cultivars contained much higher amounts of p-hydroxybenzoic acid, ferulic acid, aesculin, and naringin, that, together with detected 3-O-(6″-O-p-coumaroyl)-hexoside, apigenin, apigenin 7-O-rutinoside, and hispidulin, indicated a clear difference between the species and might represent phenolics responsible for psylla resistance.
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•Phenyllactic acid enhanced malic acid, citric acid, succinic acid contents in pears.•Phenyllactic acid regulated organic acids metabolism in pears.•Phenyllactic acid enhanced salicylic acid content ...in pears.•Phenyllactic acid up-regulated the key gene expressions in salicylic acid synthesis.
Acidity plays a crucial role in determining the sensory attributes of the majority of fresh fruit and vegetables. This study investigated the variations of organic acids metabolism and salicylic acid biosynthesis in Zaosu pears after postharvest phenyllactic acid dipping. Results elucidated that phenyllactic acid dipping improved the contents of malic, succinic, citric, and salicylic acid in Zaosu pears. Phenyllactic acid also improved the enzymatic activities and gene transcription levels of phosphoenolpyruvate carboxylase, mitochondrial citrate synthase, mitochondrial aconitase, and NADP-isocitrate dehydrogenase, whereas declined NADP-dependent malate (NADP-ME) and cytoplasmic aconitase activities as well as PbNADP-ME transcription level in pears. Moreover, the enzymatic activities and gene transcription levels of phenylalanine ammonia lyase and shikimate dehydrogenase as well as the gene transcription levels of 3-dehydroquinate synthase, d-arabino-heptulosonate-7-phosphate synthase, chorismate synthase, shikimate kinase, isochorismate synthase, 5-enolppyruvylshikimate-3-phosphate synthetase, avrPphB susceptible 3, enhanced pseudomonas susceptibility 1, enhanced disease susceptibility 5, and chorismate mutase in Zaosu pears were promoted by phenyllactic acid treatment. Taken together, phenyllactic acid can regulate the pivotal enzyme activity and gene transcription in organic acids metabolism and salicylic acid biosynthesis to sustain the flavor and freshness of Zaosu pears.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In recent years, an unusual wilt disease affecting Pyrus pyrifolia has been observed in various regions of Jiangsu, China. This disease originates from the roots and progresses with distinctive ...browning patterns along vascular tissues, even extending over two meters above the ground. These symptoms set it apart from recognized pear diseases and typically lead to the death of affected trees within the same or the following year. Furthermore, this disease exhibits a tendency to spread to neighboring trees even after the removal of affected trees, presenting a substantial threat to pear production. To ascertain the causative agent, the present study encompassed pathogen isolation, morphological and molecular identification, as well as validation experiments adhering to Koch's postulates. The fungal isolates obtained were identified as Fusarium cugenangense based on characteristics of the colonies and conidia, in addition to a phylogenetic analysis using DNA sequences of the translation elongation factor 1-alpha (tef1), calmodulin (CaM), and RNA polymerase second largest subunit (rpb2) genes. Pathogenicity of the isolated F. cugenangense on pear was confirmed by artificial inoculation. By introducing GFP-labeled pathogens into the roots, colonization in stem and leaf tissues was observed via fluorescence microscopy and transmission electron microscopy. Furthermore, these pathogens were successfully reisolated from stems and foliage, conclusively providing evidence of systemic infection within the pear plants. To the best of our knowledge, this is the first report of F. cugenangense causing pear wilt disease in China.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Understanding ripening and senescence processes in postharvest stored fruit is key to the identification and implementation of effective treatment methods. Here, we explored the effects of exogenous ...applications of melatonin (MT) and nitric oxide (NO) on ripening and softening processes in three cultivars of European pear (Pyrus communis L.). The results showed that MT and NO played important roles in the two processes: they decreased the rate of upregulation of PcCel and PcPG, inhibited expression of ethylene synthetase genes (PcACS and PcACO), and reduced rates of respiration and ethylene production. MT increased activity of NO synthase through upregulation of expression of PcNOS that subsequently led to an increase in NO content. However, when NO synthesis was inhibited, the delaying effect of MT on fruit senescence was almost eliminated. These findings indicate that MT acted on the upstream process of NO synthesis that then delayed senescence in pear fruit.
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