Structure of calleryanin and its benzylic esters from Pyrus and Prunus

The structure of calleryanin (3,4-dihydroxybenzyl alcohol 4-O-β-d-monoglucopyranoside), which occurs in Prunus lusitanica and many Pyrus species, has been confirmed by ¹H and ¹³C NMR analysis and the structure of its benzylic esters with caffeic, protocatechuic and 4-hydroxybenzoic acids verified by catalytical hydrogenolysis. The occurrence of related compounds elsewhere in the plant kingdom is briefly reviewed.     

Breeding systems and continuing evolution in the endemic Sorbus taxa on Arran

The Arran whitebeams Sorbus arranensis and S. pseudofennica are two endemic woody plant taxa that have evolved on Arran through hybridisation. S. arranensis is a triploid hybrid between the widespread diploid S. aucuparia and the rare tetraploid S. rupicola. S. pseudofennica is a tetraploid formed by crossing between S. arranensis and S. aucuparia. In order to determine the mating systems of the two endemic species six maternal trees of each taxon together with 10-12 of their seed offspring were scored for their phenotype at three microsatellite loci and one nuclear intron locus. All seeds of S. arranensis were identical in phenotype to their maternal parents. In S. pseudofennica, 17.5% of all seeds differed in marker phenotype from their maternal parent. The proportion of seed with nonmaternal phenotypes varied significantly among maternal trees of S. pseudofennica. The results suggest that the triploid S. arranensis is an obligate apomict, whereas the tetraploid S. pseudofennica is a facultative apomict. Molecular marker analysis of three trees from Arran with an unusual leaf morphology indicates that they are the product of sexual reproduction by S. pseudofennica, and may originate from hybridisation with S. aucuparia. This research demonstrates that the Sorbus taxa on Arran are participants in an active evolutionary process generating novel biodiversity. Conservation programmes for these taxa should aim to preserve this evolutionary process rather than the individual taxonomic entities that it produces.     

杜梨铵转运蛋白基因的克隆表达及在梨属植物中的SNP分析

利用EST并结合RACE方法从杜梨幼苗克隆获得1个AMT基因(PbAMT1;2).分析显示,PbAMT1;2cDNA全长1 811 bp,开放阅读框为1 515 bp,其对应基因组DNA序列不含内含子.PbAMT1;2编码的蛋白由504个氨基酸组成,具有11个跨膜域,1个N-糖基化位点、3个酪蛋白激酶磷酸化位点和8个蛋白激酶C磷酸化位点.同源性分析发现,PbAMT1;2与其他植物的AMT具有较高的一致性,其中与百脉根LjAMT1;2的一致性为80.23%,与拟南芥AtAMT1;2的一致性为78.68%,与番茄LeAMT1;2的一致性为77.80%.系统进化树分析表明,PbAMT1;2属于AMT1亚家族.半定量RT-PCR结果显示,PbAMT1;2主要在根部表达,而在茎和叶中几乎没有表达.以杜梨、豆梨、砂梨、白梨、秋子梨和西洋梨等6种梨属植物的DNA为模板,高保真Taq酶PCR扩增AMT1;2基因ORF区DNA序列,发现6种梨属植物的AMT1;2 ORF区DNA序列长度均为1 515 bp,相似性高达99.48%,但在44个核苷酸位点中存在SNPs,导致18个氨基酸位点发生变异,多态性频率为1SNP/34.43 bp,核苷酸变异度为2.9%,氨基酸变异度为3.57%.     

Variation in Two Sorbus Species Endemic to the Isle of Arran, Scotland

A study of the morphology of plants from four species of Sorbus,S. arraensis, S. pseudofennica, S. aucuparia and S. rupicola,two of them endemic to North Arran, suggested that the originof the two endemic groups could have been by hybridization. Variation between individuals within the hybrid groups indicatesthat the two groups, probably of hybrid origin (S. arranensisand S. pseudofennica), could each consist of a set of geneticallyisolated clones reproducing by apomixis, with the possibilityin the case of S. pseudofennica of occasional genetic interchangeby sexual reproduction. The overlap of characters between the two hybrid groups suggeststhat the inflow of genetic material by hybridization and geneticmodification in these groups is continuing. Sorbus arranensis Hedl., Sorbus pseudofennica E. F. Warb., Sorbus aucuparia L., Sorbus rupicola (Syme) Hedl., interspecific hybridization, apomixis     

Identification of Pyrus Single Nucleotide Polymorphisms (SNPs) and Evaluation for Genetic Mapping in European Pear and Interspecific Pyrus Hybrids

We have used new generation sequencing (NGS) technologies to identify single nucleotide polymorphism (SNP) markers from three European pear (Pyrus communis L.) cultivars and subsequently developed a subset of 1096 pear SNPs into high throughput markers by combining them with the set of 7692 apple SNPs on the IRSC apple Infinium® II 8K array. We then evaluated this apple and pear Infinium® II 9K SNP array for large-scale genotyping in pear across several species, using both pear and apple SNPs. The segregating populations employed for array validation included a segregating population of European pear (‘Old Home’בLouise Bon Jersey’) and four interspecific breeding families derived from Asian (P. pyrifolia Nakai and P. bretschneideri Rehd.) and European pear pedigrees. In total, we mapped 857 polymorphic pear markers to construct the first SNP-based genetic maps for pear, comprising 78% of the total pear SNPs included in the array. In addition, 1031 SNP markers derived from apple (13% of the total apple SNPs included in the array) were polymorphic and were mapped in one or more of the pear populations. These results are the first to demonstrate SNP transferability across the genera Malus and Pyrus. Our construction of high density SNP-based and gene-based genetic maps in pear represents an important step towards the identification of chromosomal regions associated with a range of horticultural characters, such as pest and disease resistance, orchard yield and fruit quality.     

Pyrus elaeagrifolia und ihre Hybriden in Bulgarien

In Bulgarien kreuzt sichPyrus elaeagrifolia Pall. subsp.elaeagrifolia sowie subsp.bulgarica (Kuthath. etSachok.)Valev in beträchtlichem Masse mitPyrus communis L. undP. pyraster Burgsd., mit denen sie gemeinsam hier wachsen. Die Hybriden sind normal fruchtbar, und es wurden fünf Kombinationen von ihnen beschrieben. Vereinzelt beteiligt sich an der Kreuzung auchP. spinosa Forsk. (Syn.P. amygdaliformis Vill.), u. zw. an den Kontaktstellen des Areals vonP. elaeagrifolia mit dem Areal vonP. spinosa; drei Kombinationen wurden beschrieben. Es wurde auch die Verbreitung beider Subspezies vonP. elaeagrifolia und deren Hybriden in Bulgarien ermittelt.     

酸梨金属元素的分析

采用电感耦合等离子体发育光谱仪（ICP）对野生酸梨的金属元素进行了测试分析。结果表明：其常量元素中Ca的含量高达66.84%(mg/g),同时含有人体必需的微量元素Fe,Mn,V,Cu,Zn,Ni,Co等。及对人体有益的稀土元素Nd,Tm,Yb等。     

Pyrus cordifolia sp. nov. and two new records of Pyrus (Rosaceae) from Iran

A new species, namely Pyrus cordifolia (P. sect. Pashia) is described as new to science, and two new records including P. tamamschianiae (P. sect. Pyrus) and P. theodorovii var. latifolia (P. sect. Argyromalon) are reported for the flora of Iran. These taxa are compared with their closest relatives. Photographs and a distribution map of these taxa as well as an illustration of the new species are presented. An identification key to members of P. sect. Pashia in Iran is provided.     

Characterization of the pectin methyl-esterase gene family and its function in controlling pollen tube growth in pear (Pyrus bretschneideri)

Pectin methyl-esterases (PMEs) play crucial roles in plant growth. In this study, we identified 81 PbrPMEs in pear. Whole-genome duplication and purifying selection drove the evolution of PbrPME gene family. The expression of 47 PbrPMEs was detected in pear pollen tube, which were assigned to 13 clusters by an expression tendency analysis. One of the 13 clusters presented opposite expression trends towards the changes of methyl-esterified pectins at the apical cell wall. PbrPMEs were localized in the cytoplasm and plasma membrane. Repression of PbrPME11, PbrPME44, and PbrPME59 resulted in the inhibition of pear pollen tube growth and abnormal deposition of methyl-esterified pectins at pollen tube tip. Pharmacological analysis confirmed that reduced PbrPME activities repressed the pollen tube growth. Overall, we have explored the evolutionary characteristics of PbrPME gene family and found the key PbrPME genes that control the growth of pollen tube, which deepened the understanding of pear fertility regulation.     

Molecular cloning of beta-galactosidase from Japanese pear (Pyrus pyrifolia) and its gene expression with fruit ripening

We have cloned a cDNA fragment encoding a beta-galactosidase from Japanese pear (Pyrus pyrifolia) fruit (JP-GAL). It contained an untranslated sequence of 182 nucleotides at the 5' end, a presumptive coding sequence of 2,193 nucleotides and an untranslated sequence of 268 nucleotides including a polyadenylation signal and a poly (A) tail at the 3' end. It encoded a protein with a calculated molecular weight of 80.9 kDa which consists of 731 amino acids. Both the nucleotide and the deduced amino acid sequences showed a 98% sequence identity with that obtained from the apple beta-galactosidase cDNA. The peptide sequence obtained from the purified Japanese pear beta-galactosidase III matched the deduced amino acid sequence of SVSYDHKAIIINGQKRILISG (amino acid 25-45). Northern blot analysis showed that the probe derived from JP-GAL hybridized to a single 2.6 kb RNA. The mRNA was detected solely in the fruit; none was detected in the buds, leaves, roots or shoots of the Japanese pear. The steady-state level of the beta-galactosidase mRNA was measured during fruit ripening in three cultivars, Housui, Kousui (early ripening) and Niitaka (late ripening). The results showed that regardless of the cultivar, no JP-GAL mRNA was detected in the immature fruit. Increment of the mRNA level with fruit ripening coincided with the increase in the beta-galactosidase III activity. Our results showed that the expression of JP-GAL correlated with fruit softening and JP-GAL may be beta-galactosidase III.     

早熟砂梨ISSR-PCR反应体系的建立与优化

以我国南方主栽的早熟砂梨品种‘翠冠’Pyrus pyrifolia ‘Cuiguan’为材料,对ISSR技术体系中的模板DNA浓度、Taq DNA聚合酶用量、引物浓度、dNTP浓度、Mg2+浓度、退火温度、PCR循环数等7个主要因素进行优化和筛选,建立了适合早熟砂梨的ISSR-PCR反应体系。最终反应体系为20 μL体系中10×PCR buffer（不含Mg2+）2 μL,模板DNA浓度60 ng,TaqDNA聚合酶0.75 U,引物浓度1 μmol/L,dNTP浓度90 μmol/L,Mg2+浓度2.25 mmol/L。扩增程序为：预变性94 ℃ 5 min,变性94 ℃ 45 s,退火45 s,72 ℃延伸1 min,共42个循环,然后72 ℃再延伸10 min,4 ℃保存,用1.5%琼脂糖凝胶电泳检测多态性。     

西洋梨水孔蛋白基因家族的全基因组鉴定及表达分析

水孔蛋白(AQPs,aquaporins)是高效转运水分子的膜内在蛋白,具有丰富的多样性,在调控植物的水分关系中有重要作用。本研究利用西洋梨(Pyrus communis L.‘Bartlett’)基因组数据库,通过生物信息学手段鉴定西洋梨PcAQPs基因家族成员;并利用MEGA 6.0.5软件,采用邻接法构建系统发育树;利用GSDS 2.0软件进行基因结构分析,MEME程序进行Motif分析,AgBase v2.00程序进行GO分析;采用半定量RT-PCR技术研究PcAQPs基因组织表达情况。结果表明,西洋梨基因组中共有54个PcAQPs家族成员,均含有AQP特征结构域和保守的Motif基序,根据基因结构及系统进化分析可分为PIP、TIP、NIP和SIP等4个亚家族。不同基因间结构差别较大,但聚类关系较近的基因其结构类似。GO分析发现,多数PcAQPs基因具有转运蛋白活性,参与物质转运、应激反应、发育和代谢等生物学过程,但不同亚家族成员构成的细胞组分及参与的生物学过程具有明显差异。半定量结果表明,大多数PcAQPs基因在根、茎、叶和果实中均有表达,而且不同基因家族、不同基因间的组织表达模式存在差异。该研究为今后西洋梨PcAQPs基因的克隆和功能分析奠定了基础。     

'京白梨'结实与雌雄配子体发育的解剖学研究

以‘京白梨’、‘鸭梨’、‘雪花梨’为材料,用石蜡切片技术对其雌雄配子体发育过程进行了观察研究,并对其花粉育性、自然授粉结实率进行统计分析。结果表明:(1)‘京白梨’自然授粉结实率和花粉发芽率明显低于‘鸭梨’和‘雪花梨’;(2)京白梨从小孢子母细胞形成到成熟花粉的各个发育阶段观察到未形成小孢子或形成后很快退化、花粉囊中的花粉极少、花粉发育阶段细胞发生退化等不同类型的雄性败育个体,而且在花粉成熟阶段有部分花药中的绒毡层细胞不发生退化,花粉难以散出造成雄性败育;(3)雌配子体在大孢子母细胞发育阶段发现不能形成大孢子和大孢子形成后退化或发育不良等多种发育异常的雌配子体败育类型,而且败育频率高达36.7%。研究表明,‘京白梨’雌、雄配子体在其形成发育过程中的各种异常使其不能正常受精,最终导致坐果低下。     

Identification and functional characterization of SOC1-like genes in Pyrus bretschneideri

Flowering is a prerequisite for pear fruit production. Therefore, the development of flower buds and the control of flowering time are important for pear trees. However, the molecular mechanism of pear flowering is unclear. SOC1, a member of MADS-box family, is known as a flowering signal integrator in Arabidopsis. We identified eight SOC1-like genes in Pyrus bretschneideri and analyzed their basic information and expression patterns. Some pear SOC1-like genes were regulated by photoperiod in leaves. Moreover, the expression patterns were diverse during the development of pear flower buds. Two members of the pear SOC1-like genes, PbSOC1d and PbSOC1g, could lead to early flowering phenotype when overexpressed in Arabidopsis. PbSOC1d and PbSOC1g were identified as activators of the floral meristem identity genes AtAP1 and AtLFY and promote flowering time. These results suggest that PbSOC1d and PbSOC1g are promoters of flowering time and may be involved in flower bud development in pear.