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Risk assessment and ranking of pesticide residues in Chinese pears 被引量:10
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作者 LI Zhi-xia NIE Ji-yun +9 位作者 YAN Zhen XU Guo-feng LI Hai-fei KUANG Li-xue PAN Li-gang XIE Han-zhong WANG Cheng LIU Chuan-de ZHAO Xu-bo GUO Yong-ze 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第11期2328-2339,共12页
The presence of pesticide residues in pears is a serious health concern. This study presents the results from a 2-year investigation (2013-2014) that used gas chromatography, GS/MS and UPLC/MS-MS to measure the leve... The presence of pesticide residues in pears is a serious health concern. This study presents the results from a 2-year investigation (2013-2014) that used gas chromatography, GS/MS and UPLC/MS-MS to measure the levels of 104 pesti- cides in 310 pear samples. In 93.2% of the samples, 43 pesticides were detected, of which the maximum residue levels (MRLs) were exceeded in 2.6% of the samples. Multiple residues (two to eight compounds) were present in 69.7% of the samples; one sample contained nine pesticides and one sample contained 10. Only 6.8% of the samples did not contain residues. To assess the health risks, the pesticide residue data have been combined with daily pear consumption data for children and adult populations. A deterministic model was used to assess the chronic and acute exposures based on the Joint Meeting on Pesticide Residues (JMPR) method. A potential acute risk was demonstrated for children in the case of bifenthrin, which was found to be present at 105.36% of the acute reference dose (ARfD) value. The long- term exposure of the Chinese consumer to pesticide residues through the consumption of raw pears was far below the acceptable daily intake (ADI) criterion. Additionally, the matrix ranking scheme was used to classify risk subgroups of pesticides and pear samples. In general, 95.5% of samples were deemed to be safe and nine pesticides were classified as being of a relatively high risk. The findings indicated that the occurrence of pesticide residues in pears should not be considered a serious public health problem. Nevertheless, a more detailed study is required for vulnerable consumer groups, especially children. Continuous monitoring of pesticides in pears and tighter regulation of pesticide residue standards are recommended. 展开更多
关键词 pear pesticide residue risk assessment INTAKE risk ranking
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Effects of 1-methylcyclopropene and modified atmosphere packaging on fruit quality and superficial scald in Yali pears during storage 被引量:12
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作者 FENG Yun-xiao CHENG Yu-dou +2 位作者 HE Jin-gang LI Li-mei GUAN Jun-feng 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2018年第7期1667-1675,共9页
The Yali pear(Pyrus bretschneideri Rehd.) is susceptible to superficial scald during prolonged cold storage and at shelf life. This study investigated the effects of 1-methylcyclopropene(1-MCP) and modified atmosp... The Yali pear(Pyrus bretschneideri Rehd.) is susceptible to superficial scald during prolonged cold storage and at shelf life. This study investigated the effects of 1-methylcyclopropene(1-MCP) and modified atmosphere packaging(MAP) on changes of fruit quality and superficial scald during cold storage and at shelf life in Yali pear. Compared with MAP, the combination of MAP and 1-MCP(MAP+1-MCP) treatment reduced the carbon dioxide and ethylene content inside the packaging bag. The 1-MCP, MAP, and MAP+1-MCP treatments reduced the superficial scald index, malondialdehyde content, O2^-· production rate and relative conductivity and inhibited the accumulation of α-farnesene and conjugated trienes in the peel. 1-MCP and MAP+1-MCP treatments maintained a higher phenolic content and enhanced the catalase and superoxide dismutase activities in the fruit, while reduced activities of lipoxygenase and polyphenol oxidase in the peel preceding the onset of superficial scald. Comprehensive analysis indicated that the MAP+1-MCP treatment is the most effective method tested for improving the quality of Yali pears during cold storage and at shelf life. 展开更多
关键词 pear 1-methycyclopropene modified atmosphere packaging superficial scald BROWNING
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Optimal storage temperature and 1-MCP treatment combinations for different marketing times of Korla Xiang pears 被引量:14
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作者 JIA Xiao-hui WANG Wen-hui +3 位作者 DU Yan-min TONG Wei WANG Zhi-hua Hera Gul 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2018年第3期693-703,共11页
Maintenance of green color is the primary indicator of quality in the market evaluation of Korla Xiang pears at present and can generally be achieved through early harvesting and decreasing the storage temperature, bu... Maintenance of green color is the primary indicator of quality in the market evaluation of Korla Xiang pears at present and can generally be achieved through early harvesting and decreasing the storage temperature, but the fruit quality was reduced by early harvesting, and the decreasing storage temperature increased the risk of chilling injury. The objectives of this study were to determine the optimal storage parameters for different storage times and to find ways to preserve the green skin color of pears. Specifically, we analyzed the effects of the ethylene inhibitor, 1-methylcyclopropene (1-MCP), combined with low temperature on quality and maintenance of the green color of Korla Xiang pears during storage. We found that 1-MCP and/or low temperature reduced the loss of green color at 20℃ after being removed from cold storage. In addition, 1-MCP significantly inhibited the decline of titratable acid and ascorbic acid but had no significant effect on fruit firmness and total soluble solids. Low temperature with or without 1-MCP inhibited the release of ethylene, inhibited the decline in the stalk preservation index, inhibited the increase in decay rate and weight loss rate during storage, and inhibited the increase in the core browning index after 225 days of storage. Different storage temperatures had different effects on the quality of Korla Xiang pears. Despite inhibiting ethylene release, a storage temperature of-1.5℃ increased the respiration rate. Storage at -1.5℃ caused core browning eady during storage due to chilling injury, whereas at 2℃ core browning occurred late during storage due to senescence. In late storage, 1-MCP had no significant effect on the maintenance of Korla Xiang pear quality at 2℃. Based on these results, we determined the optimal combinations of low temperature and 1-MCP treatment to maintain pear quality while avoiding chilling injury. For different marketing times, the optimal conditions for storage until New Year's Day (a storage duration of 90 days) are 2℃ or 1-MCP combined with 2℃. For storage until the Spring Festival (a storage duration of 150 days), the optimal conditions are 0℃ or 1-MCP combined with 0℃, and for storage until May (a storage duration of 225 days), the best conditions are 1-MCP combined with -1.5℃. 展开更多
关键词 low temperature 1-methylcyclopropene Korla Xiang pear maintenance of green color QUALITY
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Penicillium and patulin distribution in pears contaminated with Penicillium expansum. Determination of patulin in pears by UHPLC-MS/MS 被引量:7
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作者 WEI Dong-mei XU Jun +3 位作者 DONG Feng-shou LIU Xin-gang WU Xiao-hu ZHENG Yong-quan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第7期1645-1651,共7页
The danger of mycotoxin contamination entering the food supply through post-harvest infection is of perennial concern to food safety experts. To explore the distribution of Penicillium expansum and diffusion of its my... The danger of mycotoxin contamination entering the food supply through post-harvest infection is of perennial concern to food safety experts. To explore the distribution of Penicillium expansum and diffusion of its mycotoxin, patulin, in blue mold-damaged pears, Pyrus bretschneideri Rehd. cv. Yali obtained from markets and orchards in China were artificially inoculated with P. expansum and assayed for patulin accumulation and degree of fungal colonization. The inoculated pears were incubated until the lesions were 5, 10, 20, or 30 mm in diameter. We sampled tissue at a range of distances from the lesion, measured the spread of Penicillium by plate colony-counting methods, and used UHPLC-MS/MS to detect and quantify the patulin concentration. More P. expansum colony-forming units were isolated from pears with a higher degree of decay. Farther from the lesion, the fewer P. expansum colonies were observed, and the lower the patulin content detected. We found a significant difference in the patulin content between samples due to lesion size, and also in tissue sampled 10 mm away from the lesion. In consideration of this finding, to ensure food safety, we recommend that when a blue mold rot lesion on pear is 5, 10, or 20 mm in diameter, 20, 30, and 40 mm beyond the lesion should be removed, respectively. If a lesion surpasses 30 mm in diameter, the whole pear should be thrown away. 展开更多
关键词 pear Penicillium expansum PATULIN food safety UHPLC-MS/MS
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Effects of Nitric Oxide on the Quality and Pectin Metabolism of Yali Pears During Cold Storage 被引量:5
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作者 LIU Li-qin DONG Yu GUAN Jun-feng 《Agricultural Sciences in China》 CAS CSCD 2011年第7期1125-1133,共9页
The effect of fumigation with 10, 20, and 30 μL L-1 nitric oxide (NO) was investigated to study the effects of NO on the quality of Yali pears during cold storage. The ethylene production, composition of cell walls... The effect of fumigation with 10, 20, and 30 μL L-1 nitric oxide (NO) was investigated to study the effects of NO on the quality of Yali pears during cold storage. The ethylene production, composition of cell walls, and cell-wall-modifying enzyme activities were measured on fruits which were fumigated with NO (20 μL L-1). The results showed that NO not only reduced the peak value of ethylene production rate, the soluble sugar, soluble solid content, maintained higher firmness, starch, and NO content, but also retarded the degradation of covalent soluble pectin, accumulation of ionic soluble pectin and water soluble pectin. Moreover, NO fumigation decreased the activities of polygalacturonase (PG) and b-galactosidase(b-Gal) and delayed the peak of PG activity of fruits. Therefore, it indicated that NO fumigation could delay the softening and ripening of Yali pears. 展开更多
关键词 pear nitric oxide cell wall material fruit softening
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Effects of 1-Methylcyclopropene on NO Content,NOS Activity,and H_2O_2 Content in Postharvest Suli Pears 被引量:2
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作者 DONG Yu LIU Li-qin GUAN Jun-feng 《Agricultural Sciences in China》 CAS CSCD 2011年第5期797-804,共8页
Studies were conducted over the effects of 1-methylcycolpropene (1-MCP) treatment on postharvest life of Suli pears (Pyrus bretschneideri Rehd.) stored at room and cold temperatures on nitric oxide (NO),nitric o... Studies were conducted over the effects of 1-methylcycolpropene (1-MCP) treatment on postharvest life of Suli pears (Pyrus bretschneideri Rehd.) stored at room and cold temperatures on nitric oxide (NO),nitric oxide synthase (NOS) activity,and hydrogen dioxide (H2O2).Results showed that the 1-MCP treatment had little effect on total soluble solids (TSS) at both room and cold temperatures.1-MCP delayed softening of Suli pear fruits,decreased respiratory rate and H2O2 accumulation,and increased NO and NOS activity at room temperature storage,while the effect of cold temperature storage was relatively inferior.There was a significant positive correlation between NOS activity and NO content.It is concluded that 1-MCP had effects on endogenous NO content and accumulation of H2O2.Similarly,H2O2 acting as a signaling molecule via regulating NO level affects the ripening and senescence of Suli pears. 展开更多
关键词 pear 1-MCP NO NOS H2O2
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Bleeding canker of pears caused by Dickeya fangzhongdai:Symptoms,etiology and biology 被引量:2
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作者 CHEN Bin TIAN Yan-li +4 位作者 ZHAO Yu-qiang WANG Jia-nan XU Zhi-gang LI Xiang HU Bai-shi 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2020年第4期889-897,共9页
Bleeding canker,a devastating disease of pear trees(Pyrus pyrifolia L.),was first reported in the 1970 s in Jiangsu,China and more recently in other provinces in China.Trees infected with bleeding canker pathogen,Dick... Bleeding canker,a devastating disease of pear trees(Pyrus pyrifolia L.),was first reported in the 1970 s in Jiangsu,China and more recently in other provinces in China.Trees infected with bleeding canker pathogen,Dickeya fangzhongdai,develop cankers on the trunks and branches,and a rust-colored mixture of bacterial ooze and tree sap could be seen all over the trunks and branches.In this study,we provided detail descriptions of the symptoms and epidemiology of bleeding canker disease.Based on pathogenic and phenotypic characterizations,we identified the causal agent of bleeding canker of pear as D.fangzhongdai.Dickeya fangzhongdai strains isolated from pear were also pathogenic on Solanum tuberosum,Brassica pekinensis,Lycopersicon esculentum,and Phalaenopsis aphrodite based on artificial inoculation,and the pathogen were more virulent on potato than that of D.solani strain.This study provides new information about this disease and bleeding canker disease of pear. 展开更多
关键词 pear BLEEDING CANKER Dickeya fangzhongdai SYMPTOMS PATHOGENICITY
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PEARS课程在儿科急诊护士急救能力培训中的应用 被引量:3
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作者 余碧艳 《护理研究(中旬版)》 2017年第6期2129-2130,共2页
[目的]探讨儿童急症的评估、识别和干预(PEARS)课程对提高儿科急诊护士急救能力的作用。[方法]采用美国心脏协会的PEARS课程对急诊护士进行培训,在培训前对护士进行理论摸底考试,培训后进行理论、技能和仿真案例考核,考核结束后进行课... [目的]探讨儿童急症的评估、识别和干预(PEARS)课程对提高儿科急诊护士急救能力的作用。[方法]采用美国心脏协会的PEARS课程对急诊护士进行培训,在培训前对护士进行理论摸底考试,培训后进行理论、技能和仿真案例考核,考核结束后进行课程评价的问卷调查。[结果]培训后护士的理论成绩(88.83分±7.86分)较培训前(76.75分±6.21分)提高(P<0.01);护师组的技能考核和仿真案例考核优秀率高于护士组(P<0.01)。[结论]儿科急诊护士经PEARS课程培训后对急诊患儿的评估、识别和干预能力提高。 展开更多
关键词 pears课程 儿科护士 急救能力 培训 生命支持
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Mathematical Evaluation Changes in Rheological and Mechanical Properties of Pears during Storage under Variable Conditions 被引量:2
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作者 Ayman H. Amer Eissa Abdul Rahman O. Alghannam Mostafa M. Azam 《Journal of Food Science and Engineering》 2012年第10期564-575,共12页
In order to better design, fabricate and control pear handling machine, we should take into account mechanical and rheological properties of pear fruits as related to handling process. The changes in rheological prope... In order to better design, fabricate and control pear handling machine, we should take into account mechanical and rheological properties of pear fruits as related to handling process. The changes in rheological properties of pears stored at 5, 15, 25 ℃ and variable (fluctuating) temperature for 12 days were evaluated in terms of elasticity and viscosity parameters using creep tests. The elasticity and viscosity parameters in creep tests in general decreased with increase in storage time both under constant and variable storage conditions. For the variable storage condition, a bulk mean temperature calculated to account for a series combination of storage time and temperature to which the pears subjected. The changes in rheological properties due to variable storage temperature were described as a function of storage time. The result indicated that except the viscosity parameter of the Maxwell component of the four-element model, it was possible to describe the changes in rheological properties as a function of storage time, which are better physical parameters to estimate the quality of pears. 展开更多
关键词 Modeling rheological and mechanical properties pears STORAGE Burger's model creep test.
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PbrARF4 contributes to calyx shedding of fruitlets in ‘Dangshan Suli’ pear by partly regulating the expression of abscission genes 被引量:1
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作者 Guoling Guo Pengfei Wei +5 位作者 Tao Yu Haiyan Zhang Wei Heng Lun Liu Liwu Zhu Bing Jia 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第2期341-354,共14页
Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (... Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (DAFB) higher levels of indoleacetic acid (IAA) and tryptophan (Trp) in calyx persistence fruitlet (CPF) than calyx shedding fruitlet (CSF) ofDanshan Suli’ pear (Pyrus bretschneideri Rhed.). Consisting with this, the activity of indolealdehyde oxidase (IAAIdO), which promotes IAA synthesis, was remarkably increased, and that of peroxidase(POD), which degrades IAA, dropped markedly in CPF but not in CSF. Further, qRT-PCR results revealed that most of 31 PbrARFs (encoding auxin response factors) in Pyrus bretschneideri were highly expressed in CPF, whereas PbrARF4, PbrARF24 and PbrARF26 were significantly downregulated in CPF vis-a-vis CSF. Phylogenetic analysis revealed that 6 PbrARFs clustered in the group III, where PbrARF4 showed the closest affinity with AtARF1 that promotes organ abscission, indicating a putative role of PbrARF4 in mediating the process of calyx shedding in pear. In fact, the ectopic overexpression of PbrARF4 in Solanum lycopersicum resulted in an earlier-formed and deeper abscission layer (AL) in the transgenic plants, whose calyxes were more prone to wilt at the mature red stage (MR) compared with the control plants (wild-type). More importantly, expression levels of the abscission genes SILS and Sl Cel2 in transgenic plants overexpressing PbrARF4 were significantly upregulated in comparation with the WT, whereas those of Sl BI and Sl TAPG2 were considerably inhibited. Further, PbrJOINTLESS and PbrIDA,the two genes related to calyx shedding in pear, were up-regulated more in CSF than CPF. The findings contribute to a better understanding of PbrARFs involved in fruitlet calyx shedding of pear, which could prove beneficial to improving the quality of pear fruit. 展开更多
关键词 pear Pyrus bretschneideri Rehd Calyx shedding IAA PbrARF4 Abscission genes
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E3 ubiquitin ligase PbrATL18 is a positive factor in pear resistance to drought and Colletotrichum fructicola infection 被引量:1
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作者 Likun Lin Qiming Chen +4 位作者 Kaili Yuan Caihua Xing Qinghai Qiao Xiaosan Huang Shaoling Zhang 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第3期698-712,共15页
The Arabidopsis Toxicos en Levadura(ATL)protein is a subfamily of the E3 ubiquitin ligases,which exists widely in plants and is extensively involved in plant growth and development.Although the ATL family has been ide... The Arabidopsis Toxicos en Levadura(ATL)protein is a subfamily of the E3 ubiquitin ligases,which exists widely in plants and is extensively involved in plant growth and development.Although the ATL family has been identified in other species,such as Arabidopsis,Oryza sativa,and grapevine,few reports on pear ATL gene families have been reported.In this study,92 PbrATL genes were identified and analyzed from the Pyrus breschneideri genome.Motif analysis and phylogenetic tree generation divided them into nine subgroups,and chromosome localization analysis showed that the 92 PbrATL genes were distributed in 16 of 17 pear chromosomes.Transcriptome data and quantitative real-time polymerase chain reaction(qRT-PCR)experiments demonstrated that PbrATL18,PbrATL41,and PbrATL88 were involved in both pear drought resistance and Colletotrichum fructicola infection.In addition,Arabidopsis thaliana overexpressing PbrATL18 showed greater resistance to drought stress than the wild type(WT),and PbrATL18-silenced pear seedlings showed greater sensitivity to drought and C.fructicola infection than the controls.PbrATL18 regulated plant resistance by regulating chitinase(CHI),phenylalanine ammonia-lyase(PAL),polyphenol oxidase(PPO),catalase(CAT),peroxidase(POD),and superoxide dismutase(SOD)activities.This study provided a reference for further exploring the functions of the PbrATL gene in drought resistance and C.fructicola infection. 展开更多
关键词 pear Colletotrichum fructicola Arabidopsis Toxicos en Levadura(ATL) Drought stress
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The PcHY5 methylation is associated with anthocyanin biosynthesis and transport in ‘Max Red Bartlett' and ‘Bartlett' pears
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作者 WEI Wei-lin JIANG Fu-dong +6 位作者 LIU Hai-nan SUN Man-yi LI Qing-yu CHANG Wen-jing LI Yuan-jun LI Jia-ming WU Jun 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第11期3256-3268,共13页
The red coloring of pear fruits is mainly caused by anthocyanin accumulation. Red sport, represented by the green pear cultivar ‘Bartlett’(BL) and the red-skinned derivative ‘Max Red Bartlett’(MRB), is an ideal ma... The red coloring of pear fruits is mainly caused by anthocyanin accumulation. Red sport, represented by the green pear cultivar ‘Bartlett’(BL) and the red-skinned derivative ‘Max Red Bartlett’(MRB), is an ideal material for studying the molecular mechanism of anthocyanin accumulation in pear. Genetic analysis has previously revealed a quantitative trait locus(QTL) associated with red skin color in MRB. However, the key gene in the QTL and the associated regulatory mechanism remain unknown. In the present study, transcriptomic and methylomic analyses were performed using pear skin for comparisons between BL and MRB. These analyses revealed differential PcHY5 DNA methylation levels between the two cultivars;MRB had lower PcHY5 methylation than BL during fruit development, and PcHY5 was more highly expressed in MRB than in BL. These results indicated that PcHY5 is involved in the variations in skin color between BL and MRB. We further used dual luciferase assays to verify that PcHY5 activates the promoters of the anthocyanin biosynthesis and transport genes PcUFGT, PcGST, PcMYB10 and PcMYB114, confirming that PcHY5 not only regulates anthocyanin biosynthesis but also anthocyanin transport. Furthermore, we analyzed a key differentially methylated site between MRB and BL, and found that it was located in an intronic region of PcHY5. The lower methylation levels in this PcHY5 intron in MRB were associated with red fruit color during development, whereas the higher methylation levels at the same site in BL were associated with green fruit color. Based on the differential expression and methylation patterns in PcHY5 and gene functional verification, we hypothesize that PcHY5, which is regulated by methylation levels, affects anthocyanin biosynthesis and transport to cause the variations in skin color between BL and MRB. 展开更多
关键词 pear PcHY5 DNA methylation ANTHOCYANIN biosynthesis and transport
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Evaluation of the early defoliation trait and identification of resistance genes through a comprehensive transcriptome analysis in pears
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作者 SHAN Yan-fei LI Meng-yan +5 位作者 WANG Run-ze LI Xiao-gang LIN Jing LI Jia-ming ZHAO Ke-jiao WU Jun 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第1期120-138,共19页
Early defoliation,which usually occurs during summer in pear trees,is gradually becoming a major problem that poses a serious threat to the pear industry in southern China.However,there is no system for evaluating the... Early defoliation,which usually occurs during summer in pear trees,is gradually becoming a major problem that poses a serious threat to the pear industry in southern China.However,there is no system for evaluating the responses of different cultivars to early defoliation,and our knowledge of the potential molecular regulation of the genes underlying this phenomenon is still limited.In this study,we conducted field investigations of 155 pear accessions to assess their resistance or susceptibility to early defoliation.A total of 126 accessions were found to be susceptible to early defoliation,and only 29 accessions were resistant.Among them,19 resistant accessions belong to the sand pear species(Pyrus pyrifolia).To identify the resistance genes related to early defoliation,the healthy and diseased samples of two sand pear accessions,namely,the resistant early defoliation accession‘Whasan’and the susceptible early defoliation accession‘Cuiguan’,were used to perform RNA sequencing.Compared with‘Cuiguan’,a total of 444 genes were uniquely differentially expressed in‘Whasan’.Combined with GO and KEGG enrichment analyses,we found that early defoliation was closely related to the stress response.Furthermore,a weighted gene co-expression network analysis revealed a high correlation of WRKY and ethylene responsive factor(ERF)transcription factors with early defoliation resistance.This study provides useful resistant germplasm resources and new insights into potentially essential genes that respond to early defoliation in pears,which may facilitate a better understanding of the resistance mechanism and molecular breeding of resistant pear cultivars. 展开更多
关键词 pear early defoliation resistance and susceptibility evaluation RNA-SEQ WRKY ERF
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Botou:City of Pears
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《China Today》 1999年第2期66-68,共3页
关键词 ZHANG Botou:City of pears
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Pear genomes display significant genetic diversity and provide novel insights into the fruit quality traits differentiation
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作者 Baopeng Ding Haifei Hu +14 位作者 Yunpeng Cao Ruirui Xu Yujing Lin Tahir ul Qamar Muhammad Yuqin Song Guangqi He Youzhi Han Huangping Guo Jun Qiao Jianguo Zhao Xinxin Feng Sheng Yang Xuhu Guo Rajeev Kumar Varshney Liulin Li 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第6期1274-1290,共17页
The pear(Pyrus spp.)is well known for diverse flavors,textures,and global horticultural importance.However,the genetic diversity responsible for its extensive phenotypic variations remains largely unexplored.Here,we d... The pear(Pyrus spp.)is well known for diverse flavors,textures,and global horticultural importance.However,the genetic diversity responsible for its extensive phenotypic variations remains largely unexplored.Here,we de novo assembled and annotated the genomes of the maternal(PsbM)and paternal(PsbF)lines of the hybrid‘Yuluxiang'pear and constructed the pear pangenome of 1.15 Gb by combining these two genomes with five previously published pear genomes representing cultivated and wild germplasm.Using the constructed pangenome,we identified 21224 gene PAVs(Presence-absence variation)and 1158812 SNPs(Single Nucleotide Polymorphism)in the non-reference genome that were absent in the PsbM reference genome.Compared with SNP markers,PAV-based analysis provides additional insights into the pear population structure.In addition,some genes associated with pear fruit quality traits have differential occurrence frequencies and differential gene expression between Asian and European populations.Moreover,our analysis of the pear pangenome revealed a mutated SNP and an insertion in the promoter region of the gene PsbMGH3.1 potentially enhance sepal shedding in‘Xuehuali'which is vital for pear quality.PsbMGH3.1 may play a role in the IAA pathway,contributing to a distinct low-auxin phenotype observed in plants by heterologously overexpressing this gene.This research helps capture the genetic diversity of pear populations and provides genomic resources for accelerating breeding. 展开更多
关键词 pear Phased diploid genome Pangenome PAV Fruit quality
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Genomic selection of eight fruit traits in pear
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作者 Manyi Sun Mingyue Zhang +8 位作者 Satish Kumar Mengfan Qin Yueyuan Liu Runze Wang Kaijie Qi Shaoling Zhang Wenjing Chang Jiaming Li Jun Wu 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第2期318-326,共9页
Genomic selection (GS) has the potential to improve selection efficiency and shorten the breeding cycle in fruit tree breeding. In this study,we evaluated the effect of prediction methods, marker density and the train... Genomic selection (GS) has the potential to improve selection efficiency and shorten the breeding cycle in fruit tree breeding. In this study,we evaluated the effect of prediction methods, marker density and the training population (TP) size on pear GS for improving its performance and reducing cost. We evaluated GS under two scenarios:(1) five-fold cross-validation in an interspecific pear family;(2) independent validation. Based on the cross-validation scheme, the prediction accuracy (PA) of eight fruit traits varied between 0.33 (fruit core vertical diameter)and 0.65 (stone cell content). Except for single fruit weight, a slightly better prediction accuracy (PA) was observed for the five parametrical methods compared with the two non-parametrical methods. In our TP of 310 individuals, 2 000 single nucleotide polymorphism (SNP) markers were sufficient to make reasonably accurate predictions. PAs for different traits increased by 18.21%-46.98%when the TP size increased from 50to 100, but the increment was smaller (-4.13%-33.91%) when the TP size increased from 200 to 250. For independent validation, the PAs ranged from 0.11 to 0.45 using rrBLUP method. In summary, our results showed that the TP size and SNP numbers had a greater impact on the PA than prediction methods. Furthermore, relatedness among the training and validation sets, and the complexity of traits should be considered when designing a TP to predict the test panel. 展开更多
关键词 pear PYRUS Prediction method TP size SNP marker number
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Effects of 1-methylcyclopropene on skin greasiness and quality of'Yuluxiang'pear during storage at 20℃
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作者 Wanting Yu Xinnan Zhang +3 位作者 Weiwei Yan Xiaonan Sun Yang Wang Xiaohui Jia 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第7期2476-2490,共15页
During storage at 20℃,specific pear cultivars may exhibit a greasy texture and decline in quality due to fruit senescence.Among these varieties,‘Yuluxiang’is particularly susceptible to peel greasiness,resulting in... During storage at 20℃,specific pear cultivars may exhibit a greasy texture and decline in quality due to fruit senescence.Among these varieties,‘Yuluxiang’is particularly susceptible to peel greasiness,resulting in significant economic losses.Therefore,there is an urgent need for a preservative that can effectively inhibit the development of greasiness.Previous studies have demonstrated the efficacy of 1-methylcyclopropene(1-MCP)in extending the storage period of fruits.We hypothesize that it may also influence the occurrence of postharvest peel greasiness in the‘Yuluxiang’pears.In this study,we treated‘Yuluxiang’pears with 1-MCP.We stored them at 20℃while analyzing the composition and morphology of the surface waxes,recording enzyme activities related to wax synthesis,and measuring indicators associated with fruit storage quality and physiological characteristics.The results demonstrate that prolonged storage at 20℃leads to a rapid increase in skin greasiness,consistent with the observed elevations in L^(*),greasiness score,and the content of total wax and greasy wax components.Moreover,there were indications that cuticular waxes underwent melting,resulting in the formation of an amorphous structure.In comparison to controls,the application of 1-MCP significantly inhibited increments in L^(*) values as well as grease scores while also reducing accumulation rates for oily waxes throughout most stages over its shelf period,additionally delaying transitions from flaky-wax structures towards their amorphous counterparts.During the initial 7 d of storage,several enzymes involved in the biosynthesis and metabolism of greasy wax components,including lipoxygenase(LOX),phospholipase D(PLD),andβ-ketoacyl-CoA synthase(KCS),exhibited an increase followed by a subsequent decline.The activity of LOX during early shelf life(0–7 d)and the KCS activity during middle to late shelf life(14–21 d)were significantly suppressed by 1-MCP.Additionally,1-MCP effectively maintained firmness,total soluble solid(TSS)and titratable acid(TA)contents,peroxidase(POD),and phenylalanine ammonia-lyase(PAL)activities while inhibiting vitamin C degradation and weight loss.Furthermore,it restrained polyphenol oxidase(PPO)activity,ethylene production,and respiration rate increase.These findings demonstrate that 1-MCP not only delays the onset of peel greasiness but also preserves the overall storage quality of‘Yuluxiang’pear at a temperature of 20℃.This study presents a novel approach for developing new preservatives to inhibit pear fruit peel greasiness and provides a theoretical foundation for further research on pear fruit preservation. 展开更多
关键词 ‘Yuluxiang’pear skin greasiness 1-methylcyclopropene storage quality
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PbGIF1 promoting cell-proliferation in pear fruit is transcriptionally activated by Pb RR1
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作者 Huibin Wang Guangya Sha +5 位作者 Rui Gao Jianwen Pang Rui Zhai Chengquan Yang Zhigang Wang Lingfei Xu 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第3期689-697,共9页
As a cell proliferation regulator involved in wide biological processes in plants,GRF-INTERACTING FACTOR(GIF)controls different tissues development.However,whether GIF participates in fruit development remains unclear... As a cell proliferation regulator involved in wide biological processes in plants,GRF-INTERACTING FACTOR(GIF)controls different tissues development.However,whether GIF participates in fruit development remains unclear.According to transcriptome data,we identified PbGIF1was highly expressed during fruit development in cytokinins induced parthenocarpy pear.In the present study,the biofunction of PbGIF1 was initially verified.Overexpression of PbGIF1 promoted fruit size of transgenic tomato.The size of flesh fruit was not affected by cell expansion but the cell proliferation was promoted by overexpressing Pb GIF1.The accelerated cell proliferation process was also observed in PbGIF1-overexpressed transgenic pear fruit calli.The transcriptional regulation of cytokinins on PbGIF1 was further confirmed by exogenous CPPU treatments in pear fruitlets.To investigate the underlying mechanism,the cytokinins-responded factor,PbRR1,was further focused on.The results of Yeast-one-hybrid assay suggested that PbRR1 can bind to the promoter sequence of PbGIF1.The transcriptional activation of PbRR1 on PbGIF1 was also confirmed by Dual-Luciferase assays.Taken together,the results showed that cytokinins control pear fruit development via the transcriptional activation of PbGIF1 by PbRR1. 展开更多
关键词 PbGIF1 Cell proliferation pear Fruit development CYTOKININS PbRR1
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Overexpression of PbrGA2ox1 enhances pear drought tolerance through the regulation of GA_(3)-inhibited reactive oxygen species detoxification and abscisic acid signaling
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作者 Guoling Guo Haiyan Zhang +10 位作者 Weiyu Dong Bo Xu Youyu Wang Qingchen Zhao Lun Liu Xiaomei Tang Li Liu Zhenfeng Ye Wei Heng Liwu Zhu Bing Jia 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第9期2989-3011,共23页
Drought stress is a devastating natural disaster driven by the continuing intensification of global warming,which seriously threatens the productivity and quality of several horticultural crops,including pear.Gibberel... Drought stress is a devastating natural disaster driven by the continuing intensification of global warming,which seriously threatens the productivity and quality of several horticultural crops,including pear.Gibberellins(GAs)play crucial roles in plant growth,development,and responses to drought stress.Previous studies have shown significant reductions of GA levels in plants under drought stress;however,our understanding of the intrinsic regulation mechanisms of GA-mediated drought stress in pear remains very limited.Here,we show that drought stress can impair the accumulation of bioactive GAs(BGAs),and subsequently identified PbrGA2ox1 as a chloroplast-localized GA deactivation gene.This gene was significantly induced by drought stress and abscisic acid(ABA)treatment,but was suppressed by GA_(3)treatment.PbrGA2ox1-overexpressing transgenic tobacco plants(Nicotiana benthamiana)exhibited enhanced tolerance to dehydration and drought stresses,whereas knock-down of PbrGA2ox1 in pear(Pyrus betulaefolia)by virus-induced gene silencing led to elevated drought sensitivity.Transgenic plants were hypersensitive to ABA,and had a lower BGAs content,enhanced reactive oxygen species(ROS)scavenging ability,and augmented ABA accumulation and signaling under drought stress compared to wild-type plants.However,the opposite effects were observed with PbrGA2ox1 silencing in pear.Moreover,exogenous GA_(3)treatment aggravated the ROS toxic effect and restrained ABA synthesis and signaling,resulting in the compromised drought tolerance of pear.In summary,our results shed light on the mechanism by which BGAs are eliminated in pear leaves under drought stress,providing further insights into the mechanism regulating the effects of GA on the drought tolerance of plants. 展开更多
关键词 pear GIBBERELLIN drought stress PbrGA2ox1 reactive oxygen species abscisic acid
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Zhaoxian County,Home of the Pears
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作者 LIU JI and GONG JIANHUA 《China Today》 1996年第5期52-55,共4页
ZhaoxianCounty,HomeofthePearsByLIUJIandGONGJIANHUAZHAOXIAN(Zhaozhouinancienttimes)CountryinHebeiProvinceinNo... ZhaoxianCounty,HomeofthePearsByLIUJIandGONGJIANHUAZHAOXIAN(Zhaozhouinancienttimes)CountryinHebeiProvinceinNorthChina,withahis... 展开更多
关键词 Zhaoxian County Home of the pears
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