Fruit quality is defined by attributes that give value to a commodity.Flavor,texture,nutrition,and shelf life are key quality traits that ensure market value and consumer acceptance.In pear fruit,soluble sugars,organic acids,amino acids,and total flavonoids contribute to flavor and overall quality.Transcription factors(TFs)regulate the accumulation of these metabolites during development or in response to the environment.Here,we report a novel TF,PpbZIP44,as a positive regulator of primary and secondary metabolism in pear fruit.Analysis of the transient overexpression or RNAi-transformed pear fruits and stable transgenic tomato fruits under the control of the fruit-specific E8 promoter demonstrated that PpZIP44 substantially affected the contents of soluble sugar,organic acids,amino acids,and flavonoids.In E8::PpbZIP44 tomato fruit,genes involved in carbohydrate metabolism,amino acid,and flavonoids biosynthesis were significantly induced.Furthermore,in PpbZIP44 overexpression or antisense pear fruits,the expression of genes in the related pathways was significantly impacted.PpbZIP44 directly interacted with the promoter of PpSDH9 and PpProDH1 to induce their expression,thereby depleting sorbitol and proline,decreasing citrate and malate,and enhancing fructose contents.PpbZIP44 also directly bound to the PpADT and PpF3H promoters,which led to the carbon flux toward phenylalanine metabolites and enhanced phenylalanine and flavonoid contents.These findings demonstrate that PpbZIP44 mediates multimetabolism reprogramming by regulating the gene expression related to fruit quality compounds.

In order to explore the effects of different dilutions of alginate oligosaccharides phosphorus and potassium foliar fertilizers（APK） and different types of phosphorus and potassium foliar fertilizers on leaf and fruit traits of early-maturing sand pears, Sucui 1, a new early-maturing sand pear variety, was used as the experimental material. After flowering, four treatments were set up, including clear water（CK1）, 250 times dilution of APK, 500 times dilution of APK and 1 000 times dilution of APK. Taking early-maturing sand pear Cuiyu as the material, three foliar spraying treatments of clear water（CK2）, APK diluted 500 times solution and KH 2 PO 4 diluted 500 times solution were set up after flowering. The effects of different dilutions of alginate oligosaccharides phosphorus and potassium foliar fertilizers and different types of phosphorus and potassium foliar fertilizers on SPAD value, leaf area, specific leaf weight, single fruit weight, soluble sugar content and organic acid content of early-maturing sand pears were analyzed. The results showed that foliar application of APK diluted 500 times after flowering could significantly increase the SPAD value, specific leaf weight, single fruit weight and fruit soluble sugar content, and significantly reduce the fruit malic acid content and total acid content of Sucui 1 pear, so as to achieve the effect of increasing yield and improving quality. The SPAD value, specific leaf weight, fructase content and total sugar content of Cuiyu pear treated with 500 times dilution of APK were significantly higher than those treated with 500 times dilution of KH 2 PO 4 , and the malic acid content of fruits was significantly lower than that treated with 500 times dilution of KH 2 PO 4 . Therefore, APK as foliar fertilizer spraying is an effective nutrient management technical measure to improve the quality and efficiency of high-quality pear.

'苏翠1号'梨因其极早熟、汁多味甜、肉质细脆而深受广大消费者喜欢.为了解'苏翠1号'成熟果实主要代谢产物及代谢通路相关基因表达情况,探究其果实优异性状形成的物质和分子基础,对'苏翠1号'及其亲本'翠冠'和'华酥'成熟果实样本进行代谢组和转录组测序分析.代谢组分析.发现,3个品种间,前25个差异代谢产物主要包括有机酸、碳水化合物、氨基酸、甘油磷酸脂、脂肪酸和绿原酸.HPLC测定表明,蔗糖含量在'苏翠1号'中最高,葡萄糖含量在'翠冠'中最高,果糖含量在'苏翠1号'和'翠冠'中相似,略高于'华酥',山梨醇含量在'苏翠1号'和'华酥'中均显著低于'翠冠';苹果酸含量在'苏翠1号'中最高,柠檬酸含量在'华酥'中最高,'苏翠1号'和'华酥'总酸含量相近,均高于'翠冠'.氨基酸含量分析表明,'苏翠1号'的氨基酸总含量及天冬氨酸、苯丙氨酸、甲硫氨酸含量显著高于'翠冠'和'华酥'.转录组GO和KEGG分析表明,相较于'翠冠'和'华酥','苏翠1号'有机底物分解过程、脂质代谢、有机酸生物合成、羧酸生物合成、多糖代谢等生物学过程及代谢途径显著富集.进一步挖掘差异基因发现,糖代谢中的SPS、山梨醇代谢中的S6PDH、SDH,TCA循环中的FUMl、ICDH、PDH、OGDHL,氨基酸代谢途径中的GAT、GLSN、LASPO、SAMS,以及脂肪酸代谢中的DGK1、ACCA、KASC2、ADH、PLDA等基因在'苏翠1号'中显著高表达.这些基因可能与'苏翠1号'更活跃的蔗糖、山梨醇、氨基酸、甘油磷酯代谢及TCA循环有关.

梨新品种苏翠1号成熟期早、品质优、易成花、栽培容易,有较好的发展前景.梨主干形树形适合机械化栽培,是一种轻简化栽培树形,具有早果、丰产性好的优点.为规范该品种在主干形中应用,将几年工作进行总结,供生产参考.

[目的]明确早熟砂梨苏翠1号与其母本华酥和父本翠冠成熟期果实的果皮差异代谢产物和差异基因,解析苏翠1号果皮优良性状形成的物质和分子基础.[方法]以苏翠1号(无或极少锈)和其父本翠冠(有锈)、母本华酥(无锈)为试材,利用广靶代谢组学及高通量测序技术对3个品种成熟期果实的果皮进行代谢产物测定及转录组测序分析.通过qRT-PCR方法对差异基因进行表达水平验证.[结果]代谢组结果显示差异代谢物主要是酚酸类、脂质类和黄酮类.转录组结果显示在苯丙素合成途径,角质、栓质和蜡质生物合成途径及黄酮类生物合成途径显著富集.与翠冠比较,苏翠1号果皮中苯丙素合成途径关键酶的相关基因POD、4CL以及角质、栓质和蜡质合成途径上的HHT1、CYP86A1基因被抑制表达,CYP86B1、CER1和CAD基因显著上调,类黄酮合成途径CHS、DFR、CYP75B1、F3H和ANS基因在苏翠1号中均下调.qRT-PCR结果与测序结果相符.[结论]苯丙素合成途径以及角质、栓质和蜡质合成途径在梨果锈产生中起到了重要作用;而高黄酮醇可能使苏翠1号具有良好的耐贮性.

以砂梨苏翠1号和翠冠为材料,研究大棚栽培对果实生长发育及果实品质的影响,结果表明,大棚栽培与露地栽培果实发育期内的生长速度、单果质量增加幅度高于露地栽培,但并没有达到显著水平.大棚栽培与露地栽培果实可溶性糖含量差异显著,主要以果糖和蔗糖含量所占可溶性糖含量较高,其中苏翠1号果糖含量大棚栽培较露地栽培显著高19.36％(P<0.05),翠冠梨大棚栽培较露地栽培显著高17.63％(P<0.05).大棚栽培对砂梨果实酸组分含量影响不尽相同,除莽草酸外,果实有机酸含量及酸组分含量均有显著差异.翠冠和苏翠1号糖酸比大棚栽培较露地栽培分别显著高34.47％、44.55％(P<0.05),可溶性固形物含量均表现为大棚栽培>露地栽培,但差异未达显著水平.综合来看,砂梨大棚栽培较为适宜在徐淮地区推广.

分析梨园机械化生产的必要性和可行性,明确了梨园机械化生产是降低梨果种植成本、减轻果农劳动强度的需要,适合家庭农场、专业合作社和农业企业等多种农业生产经营形式.提出了梨园机械化生产对梨园机械设备、梨园建设和梨树树形的基本要求.推荐了适合我国梨园机械化生产的三种树形:主干形、水平棚架形和拱型棚架形,并介绍了这三种树形的基本形态、适用密度、架式和优缺点.

为研究不同品系梨早期落叶的抗性,对4个栽培梨系统98个品种(系)和4个杂交组合392个单株早期落叶情况进行了评价.结果表明,供试的西洋梨、白梨、砂梨及种间杂交种病情指数分别为54.63、37.59、30.91、52.07,不同栽培梨系统及其品种间对早期落叶抗性存在差异.杂交亲本抗性水平对后代抗性表现产生一定影响,双亲之一抗性弱,其杂种后代抗性就偏弱;双亲抗性强,更易获得综合抗性强的后代.

介绍第一届中华杯南方早熟梨评比概况，提出5点启示（即梨果生产不能只重品种而轻栽培，栽培技术是关键，梨园中早熟品种比例应合理，早熟品种没必要长期贮藏，梨品种在不断出新），最后介绍了8个适合中国南方梨区栽培的(特)早熟梨品种的主要性状。

[目的]克隆豆梨硝酸还原酶基因(PcNR),并对其序列特征、表达特点及酶活性进行分析.[方法]采用电子克隆、RT-PCR和长片段PCR,得到PcNR的eDNA和DNA序列,利用生物信息学方法进行序列分析,半定量RT-PCR检测其表达特点,并测定硝酸还原酶活性.[结果]获得了豆梨硝酸还原酶基因(PcNR)的cDNA编码区,其长度为2 712 bp,编码903个氨基酸,对应的基因组DNA序列长4 115bp,包括4个外显子和3个内含子.PcNR编码的多肽含有硝酸还原酶特征序列:含钼因子、血红素结合区域和FAD绑定区域,属于NADH型硝酸还原酶.PcNR与湖北海棠MhNR(JN632526)、桃PpNR(AB061670)和野草莓FvNR (XM_004300392)蛋白间的相似性较高,并与蔷薇科植物NR处于系统进化树的同一分枝上.在无氮处理的豆梨叶片中几乎检测不到PcNR的表达;随着培养液中NO3-浓度的提高,其表达量先上升后下降;此外,供氮时间、环境温度及光照均可调控该基因的表达.豆梨叶片中硝酸还原酶的活性变化规律与PcNR表达量变化趋势相一致.[结论]首次从豆梨中克隆获得PcNR基因的cDNA和DNA序列,揭示了其序列特征,并对调控该基因表达和硝酸还原酶活性的相关因素进行分析,为开展梨砧木氮素营养研究提供资料.

The HD-Zip transcription factors, which are unique to plant kingdom, belong to Homeobox proteins. They are composed of highly conserved HD (Homeodomain) and Leu zipper (Zip) element. The former binds specifically to DNA and the later mediates the formation of dimerization. Based on the structure features, HD-Zip transcription factors can be classified into four subfamilies HD-Zip I - IV, which are involved in different biological processes of plants including growth and development, photomorphogenesis, flowering, fruit ripening, and adaptation response to environmental stresses. HD-Zip transcription factors act as the integrators of development and environmental cues and endogenous hormone signal pathway to regulate targeted gene expression and plants adaptation response. In this review, the most advanced researches on biological functions of HD-Zip were summarized based on the researches of Arabidopsis HD-Zip transcription factors and the results from other species. The aim of this article is to provide the basis for studying the functions of new genes encoding HD-Zip proteins from other species and illustrating the molecular mechanism of HD-Zip on growth and development of plant under normal and unfavorable conditions.

Calcineurin B-like protein(CBLs),as a plant calcium sensor,plays critical role in the regulation of plant growth and stress response process. However,CBL2 gene sequence feature,expressioncharacteristic and physiological function in birch-leaf pea(rPyrus betulaefolia Bunge)are largely unknown. In this study,we isolated the cDNA,genomic DNA and its responding promoter sequences of PbCBL2 gene from birch-leaf pear seedlings by EST database mining,rapid amplification of cDNA ends(RACE) and genome walking approaches. The results have showed that PbCBL2 cDNA sequence contained a 681 bp open reading frame which encoded 226 amino acid residues. The length of genomic DNA sequence was 1 927 bp which consists of 8 exons and 7 introns. The promoter region of PbCBL2 harbored some specific regulatory elements or motifs,such as light responsive element,cis-acting regulatory element essential for the anaerobic induction,gibberellin-responsive element and cis-acting element involved in salicylic acid responsiveness. The deduced PbCBL2 polypeptide had four EF-hand structure domain(s58–71,95–106, 132–143 and 176–187 amino acids)which was necessary for calcium-binding and one calcineurin A subunit binding sites(156–171 amino acids). Semi-quantitative RT-PCR and prokaryotic expression analyses validated that the mRNA abundance of PbCBL2 is responsive to different abiotic stresses. However,PbCBL2 expression was barely detected in roots and leafs of birch-leaf pear seedling without abiotic stresses treatment. The inhibition effects on BL21(DE3)growth causing by NaCl,mannitol or PEG6000 were significantly alleviated after PbCBL2 gene transformation. Our studies have suggested that PbCBL2 gene has the inherent characteristics of the CBLs gene family in plants,which transcription level is respond to salt,drought,osmotic stresses and ABA treatment. E. coli BL21(DE3)tolerance to salt stress and osmotic stress was enhanced by transferred PbCBL2.

‘Sucui 2',a new early season pear cultivar,was derived from the cross between Huasu and Cuiguan cultivar. Its fruit is round in shape with yellow-green skin(no/less russet spot); dots are middle sized. The flesh is white,crisp and juicy,containing soluble solids of about 12%. The average fruit weight is about 270 g. It matures in middle to late July in Nanjing area, Jiangsu Province,with a fruit development period of about 115 d. The tree is half-open and easy to produce flower buds with higher fruit setting rate.

为明确梨砧木豆梨(Pyrus calleryana Dcne.)磷转运蛋白质基因的序列特点和表达模式,采用同源克隆、RACE技术和染色体步移法克隆获得1个Pht基因PcPht1的cDNA、DNA及启动子序列,并利用RT-PCR检测在不同供磷水平下该基因在豆梨幼苗中的表达情况.结果表明PcPht1 cDNA序列编码区长1 617 bp,编码1个由538个氨基酸组成的蛋白质,其相对分子质量为5.908× 104.该基因编码区DNA序列没有内含子,其启动子除了具有TATA/CAAT-box外还包含防御与胁迫响应元件、光响应元件和茉莉酸甲酯响应顺式作用元件.PcPht1所编码蛋白质由12个疏水的跨膜区域组成,包括H2PO4-/nH+共运体、糖转运体和MFS通用底物转运体3个Pht1蛋白质特征结构域.PcPht1与大豆GmPht1;07和橡胶HbPht1间有较高的一致性(分别为88.0％和87.0％);与拟南芥Pht1蛋白质家族处于系统进化树的同一分支,并与AtPht1;4和AtPht1;7的亲缘关系最近.正常供磷条件下,PcPht1基因主要在根中表达,低磷时该基因的表达上调,提高供磷浓度其表达受到抑制,说明PcPht1的表达受环境磷浓度调控.

‘Sucui 1'is a new sand pear cultivar with early maturity which is derived from‘Huasu'× ‘Cuiguan'.The tree is half-spreading and easy to produce flower buds.It ripens in middle-July in Nanjing.The fruit shape is obovate with yellow greenish skin and no rust.Its average fruit mass is 260 g.The flesh is crisp,tender,richer juice,sweet,with 12.5% ~ 13.0% soluble solids content.The cultivar also has early bearing and high yield character.

Phytochelatins play a major role in metal detoxification in plants. However, the molecular mechanisms of heavy metal detoxification remain unknown, and birch-leaf pear genes related to metal detoxification have not yet been identified. Here, we report the isolation of cDNA and genomic DNA sequences encoding a phytochelatin synthase (PCS) from birch-leaf pear (Pyrus betulaefolia Bunge). The PbPCS1 cDNA sequence contained 1,965 nucleotides of a 1,494 bp open reading frame (ORF), which encodes a 497-amino-acid protein with a molecular weight of 55.00 kDa. Its corresponding genomic DNA sequence consists of 3,820 nucleotides and eight exons separated by seven introns. The deduced amino acid sequence of PbPCS1 contains five Cys residues (56, 90, 91, 109 and 113 amino acids) that are highly conserved in the plant PCS1 family, and 12 cysteine residues putatively involved in heavy metal binding sites, which included three adjacent Cys–Cys components (331–332, 351–352 and 369–370 amino acids) in the C-terminal variable domain. Homology analysis of the deduced PbPCS1 amino acid sequence revealed that it shares a high sequence similarity amongst N-terminal amino acids and low similarity with C-terminal amino acids with plant PCS1 proteins deposited with NCBI. PbPCS1 was most related to PCS1 from legume plants Lotus japonicus (GenBank accession no. AAT80342) and soybean (Glycine max L.; AAL78384) as they were clustered into the same clade in a neighbor-joining phylogenetic tree. Quantitative real-time PCR (qPCR) expression analysis revealed that PbPCS1 had a very low basal expression level in untreated whole seedlings, and levels were higher in roots than in leaves and stems. After 24 h of exposure to 20 μM CdSO4, CuSO4 or ZnSO4, PbPCS1 expression increased significantly in different organs. In addition, L-buthionine-sulfo-ximine (BSO) can inhibit PbPCS1 expression in roots, stems and leaves, while L-glutathionereduced (GSH) stimulates PbPCS1 expression in different organs of birch-leaf pear.

以豆梨的茎段为外植体进行离体繁殖体系研究,探讨4种基本培养基(MS、AS、NN69、WPM)及6-BA、NAA不同配比对豆梨组织培养增殖率的影响。试验结果表明,豆梨组培苗的适宜增殖培养基为MS+6-BA 0.6 mg/L+NAA 0.2 mg/L;适宜的培养方式为,在MS+6-BA 0.6 mg/L+NAA 0.2 mg/L培养基上继代2次后转到空白培养基继代培养1次;适宜生根培养基为1/2MS+IBA 1.5 mg/L。

<正>盐胁迫是限制作物生长和产量的主要环境因素之一,它直接导致植物组织和细胞的水分丧失。为了防御细胞失水,植物积累渗透保护物质甘氨酸甜菜碱(Glycine betaine,GB)来维持植物细胞的渗透平衡[1]。植物GB合成以甜菜碱醛为底物,由甜菜碱醛脱氢酶(BADH)催化生成。不同植物BADH基因的mRNA转录水平均受到盐胁迫诱导上[2-5]

[Objective]The incidence of pear rust(Gymnosporangium haraeanum Syd.) in field and influencing factors were studied in order to provide scientific reference for identifying pear rust resistance.[Method]Hybrid seedlings of Cuiguan× Jinxing were used for investigating the pear rust incidences using natural rust infection in field and artificial inoculation method,and correlation analysis was conducted with other factors.[Result]Rust-resistance in the hybrids seedling showed extensive segregation.Probability distribution of rust disease index of pear seedling varied greatly among different years and different periods in the same year.The distribution curve of disease showed multi-peaks under field conditions.While,it showed single peak in case of artificial inoculation.Moreover,a significantly negative correlation was observed between distance of juniper and pear and disease index,which increased year after year.[Conclusion]Rust-resistance of pear seedling varied in different years or even in the same year.This difference might be due to the infection of different physiological race of pear rust.Therefore,the pathogen should be artificially inoculated many times to select highly resistant strain,and the distance between pear and juniper plants should be considered in screening stronger rust-resistant pear variety in field.

N-methylation of phosphoethanolamine,the committing step in choline biosynthesis in plants,is catalyzed by phosphoethanolamine N-methyltransferase(PEAMT,EC 2.1.1.103).Herein we report the cloning and characterization of a novel birch-leaf pear(Pyrus betulaefolia) phosphoethanolamine N-methyltransferase gene(PbPEAMT) using a combination of homologous cloning,PCR and bioinformatics strategy.At the same time,semi-quantitative PCR with cross-intron primers was adopted to study the expression features of this gene under abiotic stresses.The results showed that the DNA sequence of PbPEAMT gene is 3 320 bp,which consists of 11 exons and 10 introns.The cDNA sequence of PbPEAMT gene is 1 479 bp in length and encodes a 492-amino-acid peptide,which includes two conserved motifs of type II methyltransferase.Homology analysis showed that the deduced PbPEAMT protein was highest homologous to castor PEAMT protein(86%).Furthermore,PbPEAMT was more related to castor PEAMT through phylogenetic analysis.RT-PCR analysis showed that expression of PbPEAMT was induced by 100 mmol·L-1 NaCl,10%(W/V) PEG6000,180 mmol·L-1 mannitol or 20 μmol·L-1 ABA treatments.These data indicate that PbPEAMT expression responds to salinity,drought and osmotic stresses,which may be involved in ABA-mediated stress signal transduction pathway.