The large‐scale production of pathogen-tested planting material remains a major challenge in pear (Pyrus spp.), particularly for genotypes that are recalcitrant to in vitro establishment, multiplication, and rooting, and are frequently affected by mixed virus and viroid infections. Here, we developed an integrated in vitro propagation and sanitation pipeline for Pyrus ussuriensis Maxim. ‘Jingbaili’, combining genotype‐tailored culture initiation, chemotherapy‐thermotherapy‐shoot tip culture, molecular diagnosis, and optimized proliferation and rooting protocols. Semi‐lignified young shoots harvested in April were identified as the most suitable explant type for establishing aseptic cultures. During culture initiation, a stepwise increase in plant growth regulator concentrations over three successive subcultures enhanced shoot vigor and suppressed hyperhydricity. RT‐PCR screening of the source material detected apple stem grooving virus (ASGV), apple stem pitting virus (ASPV), apple chlorotic leaf spot virus (ACLSV), and apple scar skin viroid (ASSVd). For sanitation, the combined chemotherapy‐thermotherapy‐shoot tip culture treatment achieved survival rates of 94.0

This study systematically elucidated the differences in fruit quality between bagged and non-bagged apples by integrating phenomics, transcriptomics, and metabolomics. Significant variations were observed between the two groups in peel color, single fruit weight, epidermal cells, collenchyma, cuticular wax, peel hardness, peel toughness, flesh hardness, and flavor. The content of volatile compounds, represented by 26 key aroma metabolites, was significantly higher in non-bagged fruits than in bagged ones. Compared to bagged fruits, non-bagged fruits exhibited elevated soluble sugar levels (e.g., sorbitol), accompanied by a minor increase in organic acids. In contrast, bagged fruits accumulated higher levels of free amino acids (e.g., asparagine) and their metabolites. Spatial distribution maps for L-asparagine, l-aspartate, l-glutamine, L-glutamate, sorbitol, sucrose, fructose, glucose, and malic acid in fruits were generated via mass spectrometry imaging. Furthermore, key candidate genes potentially responsible for the differential accumulation of amino acids, sugars, volatile compounds, wax, and cellulose were screened.

Mango (Mangifera indica L. cv. 'Keitt') is one of the core fruit delicacies produced by China. During the post-harvest storage span, the fungal pathogen colletotrichum gloeosporioides readily invades the fruits and leads to a significant overall yield loss. In recent years of development, the exploitation of naturally occurring fungitoxic compounds such as Sandalwood Essential Oil (SEO) has been useful in tackling various fungal species. This study demonstrates the potential of SEO as part of a storage protection strategy against C. gloeosporioides-induced postharvest anthracnose. SEO displayed a relatively higher mycelial growth inhibition rate when compared to various other essential oils. Furthermore, the Minimal Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC), and EC50 (Half maximal effective concentration) of SEO were determined to be 2000, 2500, and 610.38 mu L/L, respectively. Moreover, the chitosan glutamate-SEO emulsion controlled the anthracnose spread for several days by multiple folds at 1/2 MIC, MIC, and 2 MIC concentrations. These results strongly support the potential for largescale production and application of SEO emulsions by agrochemical firms and post-harvest storage facilities handling Keitt mangoes.

The evolution of the MADS-box gene family is essential for the rapid differentiation of floral organs and fruit types in angiosperms. Two key processes drive the evolution of gene families: gene duplication and functional differentiation. Duplicated copies provide the material for variation, while advantageous mutations can confer new functions on gene copies. In this study, we selected the Rosaceae family, which includes a variety of fruit types and flower organs, as well as species that existed before and after whole-genome duplication (WGD). The results indicate that different fruit types are associated with different copies of MADS-box gene family duplications and WGD events. While most gene copies derived from WGD have been lost, MADS-box genes not only retain copies derived from WGD but also undergo further gene duplication. The sequences, protein structures, and expression patterns of these gene copies have undergone significant differentiation. This work provides a clear example of MADS-box genes in the context of gene duplication and functional differentiation, offering new insights into the evolution of fruit types and floral organs.

The columnar growth trait of apple (Malus × domestica Borkh.) is genetically controlled by the Columnar (Co) locus on 10 chromosomes, including several candidate genes. Except for MdCo31, other candidate genes at the Co locus are less elucidated. In this study, a strategy of step-by-step screening was adopted to select 11 candidate genes by experimental cloning, transient expression, and genetic transformation. There existed several SNPs in four genes by sequence alignment in columnar and non-columnar apples. Two genes were detected in the nucleus and three genes in the cell membrane, other genes were located in multiple cellular structures by subcellular location. Ectopic expression demonstrated that more branching occurred in MdCo38-OE by upregulating NtPIN1 and NtGA2ox and enlarged leaves in MdCo41-OE tobaccos by upregulating NtCCDs. Transcripts of MdCo38 and MdCo41 were associated with the Co genotypes in apples. The results indicate that MdCo38 and MdCo41 are involved in the columnar growth phenotype in apple, probably through altering polar auxin transport, active gibberellin levels, and strigolactone biosynthesis.

The Tiller Angle Control 1 (TAC1) gene belongs to the IGT family, which mainly controls plant branch angle, thereby affecting plant form. Two members of MdTAC1 are identified in apple; the regulation of apple branch angle by MdTAC1 is still unclear. In this study, a subcellular localization analysis detected MdTAC1a in the nucleus and cell membrane, but MdTAC1b was detected in the cell membrane. Transgenic tobacco by overexpression of MdTAC1a or MdTAC1b showed enlarged leaf angles, the upregulation of several genes, such as GA 2-oxidase (GA2ox), and a sensitive response to light and gravity. According to a qRT-PCR analysis, MdTAC1a and MdTAC1b were strongly expressed in shoot tips and vegetative buds of weeping cultivars but were weakly expressed in columnar cultivars. In the MdTAC1a promoter, there were losses of 2 bp in spur cultivars and 6 bp in weeping cultivar compared with standard and columnar cultivars. An InDel marker specific to the MdTAC1a promoter was developed to distinguish apple cultivars and F1 progeny. We identified a protein, MdSRC2, that interacts with MdTAC1a, whose encoding gene which was highly expressed in trees with large branch angles. Our results indicate that differences in the MdTAC1a promoter are major contributors to branch-angle variation in apple, and the MdTAC1a interacts with MdSRC2 to affect this trait.

Members of the auxin/indoleacetic acid (Aux/IAA) gene family in plants are primary auxin-responsive genes that play important roles in many aspects of plant development and in responses to abiotic stress. Recently, 33 Aux/IAA have been identified in the apple genome. The biological responses of MdIAAs to salt stress are still unknown. In this study, Malus zumi, Malus baccata, and Malus × domestica 'Fuji' plantlets were subjected to salt stress by supplementing hydroponic media with NaCl at various concentrations. M. zumi showed the strongest salt resistance, followed by 'Fuji', and M. baccata was the most sensitive to salt stress. Tissue-specific expression profiles of MdIAAs were determined by quantitative real-time polymerase chain reaction. When apple plantlets were subjected to salt stress, most of salt-responsive MdIAAs were up-regulated by 1 h, 3 h, and 6 h in roots, shoot tips, and leaves, respectively. Highly expressed MdIAAs in roots, especially for M. zumi, consisted with the salt tolerance of apple rootstocks. Transgenic apple calli were tolerant to salt stress when over-expressed salt-responsive genes, MdIAA8, -9, and -25. These results provide clues about salt resistance in these three Malus species, which helps apple breeding of salt tolerance by genetic transformation.

为筛选出'京白梨'果实品质的特征性指标并建立'京白梨'优质果品的评价体系,本研究以门头沟区军庄镇东山村和孟悟村生长健壮且结果良好的'京白梨'树为试验材料,选择各单株的优质果实,分别测定和分析果实在采收时及后熟后的果实外观形状(单果重、果实纵横径、果形指数、果心大小和果肉硬度)和内在品质(可溶性固形物、可滴定酸、维生素C含量和出汁率),并通过主成分分析法筛选'京白梨'优质果实的评价指标.结果表明:'京白梨'优级果品的综合评价指标是果形指数≤0.88且单果重≥110.00 g,采收时果实可溶性固形物质量分数≥12.50％、后熟果实可溶性固形物质量分数≥15.00％;单果重、果实纵横径和果形指数可作为'京白梨'果实品质评价的主要指标,可溶性固形物含量和糖酸比可作为辅助指标.综上,本研究可指导'京白梨'的栽培生产并为优质果实采收和分级提供标准.

The dominant Co locus controls the columnar growth phenotype of apple (Malus × domestica) trees. Candidate gene MdCo31, encoding 2-oxoglutarate-dependent dioxygenase, causes dwarf growth with short internodes in transgenic plants by reducing the abundance of biologically active gibberellin. However, the pathway regulating MdCo31 in the dwarfism of apple trees remains unclear. In this study, expression of MdCo31 was proved to be negatively correlated with internode length in F1 populations created by crossing columnar parents, and with dwarfism in transgenic apple plantlets. Yeast (Saccharomyces cerevisiae) two-hybrid screening identified the RNA polymerase II transcription subunit MdMED32 as putative interactor of MdCo31. Bimolecular fluorescence complementation, co-immunoprecipitation, and dual-luciferase reporter assays confirmed this interaction both in vivo and in vitro. Ectopic expression of MdMED32 in Nicotiana tabacum led to a dwarf phenotype, similar to that of MdCo31 transgenic apple plants. Expression of GA2ox1 and GA20ox1, encoding key enzymes of gibberellin metabolism, was upregulated in transgenic plants. Transient transcriptional activity demonstrated that MdMED32 functioned as an activator, promoting expression of MdGA2ox1 and MdGA20ox1. These findings indicate that the interaction between MdCo31 and MdMED32 functions in the regulation of internode length in columnar apple.

Columnar apples are a labor saving and productive tree form that has long been of interest to apple breeders and producers. MdCo31 , which encodes a putative 2OG-Fe(II) oxygenase, is a potential candidate gene involved in controlling the internode length of columnar growth of apple. In this study, a putative regulation in internode length was conducted by exogenous application of GA 3 and paclobutrazol. The results showed that the MdCo31 -GFP fusion protein was specifically localized in the cytoplasm. Heterologous over-expression of MdCo31 in tobacco produced stunted phenotypes with high chlorophyll content in leaves, and delayed the timing of seed germination and flowering. The over-expression tobacco plants were more sensitive to exogenous application of GA 3 but insensitive to paclobutrazol, and their growth correlated to lower concentrations of endogenous GA 1 and lower expression levels of the gibberellin-regulated family gene NtGASA6 . The higher the MdCo31 expression levels were identified in more dwarf transformants with the shorter internodes. This research proposed that the decrease in endogenous GA 1 , resulting from high MdCo31 expression, induced dwarf phenotypes and shorted internodes, which indicated that MdCo31 is responded to gibberellins’ deficiency conferring the internodal growth of columnar apples.

为解决杜梨组培苗生根率低和移栽成活率低的问题,本研究以杜梨组培苗为试材,通过不定根诱导、不定根生长培养和试管苗驯化移栽环节,筛选出最适杜梨组培苗生长的培养基配方和炼苗方式.结果 表明:1)健壮组培苗在添加了1.0 mg/L吲哚乙酸(IAA)和1.0 mg/L萘乙酸(NAA)的NN69 (Nitsch&Nitsch Medium)培养基中暗培养7d后进行不定根诱导,再转接至无生长素类物质的相同培养基中光照培养,组培苗生根率达96％;2)生根组培苗闭瓶炼苗和水培炼苗3周后移栽,成活率均达90％以上.综上所述,前期"高浓度生长素和黑暗培养"和后期"无激素和光照培养"的"两步生根法"适宜杜梨组培苗的生根诱导.杜梨组培苗生根技术的优化,为杜梨无性系砧木的商业化生产提供了技术支持.

Nursery plant propagation by grafting has been widely used in modern viticulture to minimize the damage caused by biotic and abiotic stresses. In grapevine (Vitis spp.), an effective way to control disease damage is to provide producers and growers with pathogen-free stock plants. In this study, five grapevine rootstock varieties, 'SO4', '101-14', '5BB', '110R' and '1103P', were selected as explants to establish an in vitro culture protocol, and three species of grapevine viruses were tested by real-time RT-PCR. The results showed that MS medium supplemented with 0.2 mg/L IBA, 1.0 mg/L 6-BA, 0.5 mg/L KT, 4.0 mg/L adenine for culture initiation, and WPM supplemented with 0.2 mg/L IBA for subculture were suitable for all five rootstock varieties, with multiplication coefficients ranging from 1.6 to 4.4. Virus testing showed that single RT-PCR was more effective for detecting the three viruses compared to double or triple RT-PCR. Only plantlets free from the aforementioned viruses were retained for subculture. Plantlets were hardened at room temperature under natural lighting in Hoagland solution for 2 weeks and transplanted to pots filled with mixed media in a greenhouse. This protocol is applicable for rapid propagation of the five grapevine rootstock varieties and can be used for commercial production of virus-free grapevine stocks.

卓越农林人才培养是高等农林教育综合改革的突破口和关键环节,中国农业大学园艺学科是教育部首批“复合应用型”人才培养的试点学科.针对现代园艺产业多层次的人才需求、研究型大学的定位、应用性强的学科特点和学生职业规划的多样性要求,探索适合研究型高校应用型学科本科生人才培养的实践教学模式.研究融通实验教学平台、学科研究平台和校外实践平台“三平台”的优势资源,制订“递进式贯全程”的实践教学方案,通过制度建设、师资优化、教学督导和考核方式改革多种措施,保障教学体系的良好运转和自主优化,强化基本技能、科研技能和实践技能“三技能”的训练,培养具有“扎实专业知识、创新创业思维和综合应用能力”的园艺复合应用型人才.“3+3”实践教学模式,体现了“以学生为本、面向产业、服务社会”的理念,推动了园艺专业本科生的创新能力培养和个性化成才.

为加快鲜食葡萄苗木的繁殖速度,提高苗木品质,以鲜食葡萄品种夏黑、红地球、巨峰和玫瑰香为试验材料,通过对无菌外植体的消毒、继代和驯化等环节技术的探究,建立适用于不同鲜食葡萄品种的组培快繁体系.结果 表明,以葡萄茎段作为外植体在低浓度(0.3％～0.5％)次氯酸钠溶液中消毒15min后,接种在MS+0.2 mg·L-1IBA+ 1.0 mg·L-16-BA+0.5 mg·L-1KT +4.0 mg·L-1腺嘌呤+30 g·L-1蔗糖+8.2 g·L-1琼脂的培养基上,成活率达到87.5％;以培养基WPM添加0.2 mg·L-1IBA增殖培养兼生根诱导,组培苗生长健壮,生根效果好.采用水培方法炼苗3周后4个品种组培苗移栽成活率均达到100％.综上,完整的基础组培快繁体系可应用于科学研究及工业化大规模生产.本研究为加快鲜食葡萄的繁殖速度、提高苗木质量提供了理论依据.

异戊烯基转移酶(IPT)是细胞分裂素合成途径的第一限速酶,过表达苹果MdIPT3a的转基因烟草表现出典型的细胞分裂素特异的生长表型,可作为苹果同源转基因的潜在筛选标记.为阐明MdIPT3a自主启动子对基因表达的调控作用,本试验克隆了富士苹果MdIPT3a基因上游启动子序列,分别构建不同长度的MdIPT3a启动子驱动GUS基因的植物表达载体,以CaMV35S驱动GUS基因的表达载体作为对照,遗传转化烟草W38,并对转基因植株进行GUS定性和定量分析,探讨不同长度的MdIPT3a启动子对GUS表达的影响.结果 表明,转基因植株的各组织均有GUS染色,不同长度的MdIPT3a启动子均能驱动GUS基因表达,最小的有效启动子长446 bp,且含MdIPT3a启动子的转基因植株GUS表达水平显著低于含35S启动子的对照植株.本试验结果为MdIPT3a的同源转基因技术研究提供了一定的理论参考.

The Aux/IAA (auxin/indole-3-acetic acid) gene family is one of the early auxin-responsive gene families, which play a central role in auxin response. Few reports are involved in Aux/IAA genes in fruit trees, especially in apple (Malus × domestica Borkh.). A total of 33 MdIAA members were identified, of which 27 members contained four conserved domains, whereas the others lost one or two conserved domains. Several cis-elements in promoters of MdIAAs were predicted responsive to hormones and abiotic stress. Tissue-specific expression patterns of MdIAAs in different apple tree ideotypes were investigated by quantitative real-time PCR. A large number of MdIAAs were highly expressed in leaf buds and reproductive organs, and MdIAAs clustered in same group showed similar expression profiles. Overexpression of MdIAA18 in Arabidopsis resulted in compact phenotype. These results indicated that MdIAA genes may be involved in vegetative and reproductive growth of apple. Taken together, the results provide useful clues to reveal the function of MdIAAs in apple and control apple tree architecture by manipulation of MdIAAs.

Columnar trait of apple (Malus × domestica Borkh.) is controlled by a single dominant Columnar (Co) gene,located in apple genome chromosome 10.Many putative genes are predicted in the Co region.Screening genes related to the columnar trait in apple provides theoretical basis for identification of the Co gene.Sixty-four putative genes in the Co region (18.51～19.1 Mb) were screened by SRA/EST (Sequence Read Archive/Expressed Sequence Tags) database.Samples of shoot tips,leaves and buds from columnar cultivar'Wijcik'and non-columnar cultivar'McIntosh'were used to extract total RNA,respectively,and the cDNA mixture of an equal volume of each sample after reverse transcription,was used as materials to conduct.Reverse transcription PCR (RT-PCR) was to amplify partial cDNA sequences of putative gene.Quantitative Real-time PCR (qRT-PCR) reactions were performed to analyze the differential expression of putative genes in apple shoot tips.32 putative genes expressed in different apple tissues or organs were detected by searching SRA/EST database.29 putative genes were obtained by RT-PCR amplification,and 15 genes were with significant differences in apical tips of the columnar apple by qRT-PCR analysis.Among them,6 genes (No.26,No.41,No.33,No.38,No28 and No.32) were up-regulated significantly (P9＜0.05),and 9 genes (No.30,No.9,No.37,No.6,No.44,No.10,No.27,No.11 and No.4) were down-regulated significantly in apical tips of the columnar cultivar(P＜0.05).In this study,15 genes with significant differences in the apical tips of the columnar apple could be regarded as candidate genes of the Co.The candidate genes are identified to elucidate the function of critical genes and molecular mechanisms of the apple columnar mutation in the Co gene region,and serve as a directional genetic improvement for apple trees.

IGT family genes share the highly conserved motif GφL-(A/T) IGT in domain II and play an essential role in plant form. The tree architecture of apple (Malus × domestica Borkh.) affects fruit quality and yield. However, little information is available regarding IGT family genes in apple. Apple cultivars of four ideotypes (columnar, tip bearer, spur, and standard) were selected to characterize IGT family genes. Four IGT family members named MdoTAC1a, MdoTAC1b, MdoLAZY1, and MdoLAZY2 were found in the apple genome, sharing four conserved domains. In addition, MdoLAZY1 and MdoLAZY2 contain a fifth domain (EAR motif) at the C-terminus. There was no difference in the coding sequences of each gene in the four cultivars, but several mutated sites were found in their promoters. The four genes displayed lower expression levels in all tested tissues and organs of the columnar cultivar than in the other three cultivars, while expression levels of MdoTAC1a and MdoTAC1b in shoot tips and vegetative buds were highest in the standard cultivar, followed by spur, tip bearing, and columnar cultivars in decreasing order. These results indicate that IGT gene promoters are of great importance in the development of apple tree architecture and lay a theoretical basis for developing gene-specific markers for marker-assisted selection in breeding programs.

Arabidopsis SUPERMAN and its family members of its family play important roles in plant growth and floral organ development; yet much less is known about their functions expanding in apple tree development. Previous work has identified 12 SUP-like genes in the apple (Malus × domestica Borkh.) genome, and the MdSUP11 which is expressed in both vegetative and reproductive organs of apple. However, the function of MdSUP11 remains obscure. In this study, the β-glucuronidase expression driven by the MdSUP11 native promoter was detected in roots, young leaves, and floral organs of transgenic Arabidopsis. In transgenic tobacco, overexpression of MdSUP11 lead to dwarfism, aberrant leaf shapes, and morphological changes of floral organs. Endogenous concentrations of auxin (indole-3-acetic acid), abscisic acid, isopentenyl adenosine and zeatin riboside were significantly higher in young MdSUP11-transformed tobacco plants than in non-transformed plants. Gene expression analysis using real-time quantitative PCR showed up-regulation of NtDFR2 and NtANS1 expression in unopened transgenic flowers, whereas NtCHS expression was not changed significantly. Together, these results suggest that MdSUP11 is associated with apple's vegetative and reproductive development. Its overexpression in tobacco affects leaf and flower organ development and plant height; potentially by changing NtDFR2 and NtANS1 expression and endogenous levels of indole-3-acetic acid, cytokinins and abscisic acid.

As a classic plant-specific transcription factor family - the Dof domain proteins - are involved in a variety of biological processes in organisms ranging from unicellular Chlamydomonas to higher plants. However, there are limited reports of MdDof (Malus domestica Borkh. DNA-binding One Zinc Finger) domain proteins in fruit trees, especially in apple. In this study we identified 54 putative Dof transcription factors in the apple genome. We analysed the gene structures, protein motifs, and chromosome locations of each of the MdDof genes. Next, we characterised all 54 MdDofs their expression patterns under different abiotic and biotic stress conditions. It was found that MdDof6,26 not only played an important role in the biotic/abiotic stress but may also be involved in many molecular functions. Further, both in flower development and pollen tube growth it was found that the relative expression of MdDof24 increased rapidly, also with gene ontology analysis it was indicated that MdDof24 was involved in the chemical reaction and flower development pathways. Taken together, our results provide useful clues as to the function of MdDof genes in apple and serve as a reference for studies of Dof zinc finger genes in other plants.