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Author

Mingyue Zhang

Bio: Mingyue Zhang is an academic researcher from Nanjing Agricultural University. The author has contributed to research in topics: PEAR & Genetic diversity. The author has an hindex of 10, co-authored 31 publications receiving 1022 citations. Previous affiliations of Mingyue Zhang include Shandong Agricultural University.
Topics: PEAR, Genetic diversity, Population, Gene family, Gene

Papers
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Journal ArticleDOI
TL;DR: In this article, a high-quality draft genome sequence of the diploid P. bretschneideri Rehd was provided for de novo assembly of a highly heterozygous genome of this size with highly repetitive DNA sequences.
Abstract: Pear, the third most important temperate fruit species after grape and apple, belongs to the subfamily Pomoideae in the family Rosaceae. The majority of cultivated pears are functional diploids (2n = 34). As a popular fruit in the world market, pear has widespread cultivation on six continents, with major production in China, the United States, Italy, Argentina, and Spain (Supplemental Fig. 1). Pears are among the oldest of the world's fruit crops, with >3000 yr of cultivation history (Lombard and Westwood 1987), likely originating during the Tertiary period (65–55 million years ago [MYA]) in the mountainous regions of southwestern China and, from there, spreading on to both the East and West (Rubtsov 1944; Zeven and Zhukovsky 1975). Central Asia and eastern China are identified as two subcenters of genetic diversity for pear (Vavilov 1951). The Pyrus genus is genetically diverse with thousands of cultivars, but it can be divided into two major groups, Occidental pears (European pears) and Oriental pears (Asiatic pears). At least 22 primary species are well-recognized in Pyrus; however, only a few species, including Pyrus bretschneideri, Pyrus pyrifolia, Pyrus ussuriensis, Pyrus sinkiangensis, and Pyrus communis, have been utilized for fruit production. Herein, we report on a high-quality draft genome sequence of the diploid P. bretschneideri Rehd. cv. ‘Dangshansuli’ (also known as ‘Suli’), the most important commercial Asiatic pear cultivar grown in the world (>4 million tons per year), having >500 yr of cultivated history in China. Pear is highly heterozygous due to self-incompatibility and interspecies compatibility. The genome is known to have an abundance of repetitive DNA sequences. In this study, a novel combination of BAC-by-BAC (bacterial artificial chromosome) strategy, with Illumina sequencing technology, is used for the first time for de novo assembly of a highly heterozygous genome of this size with highly repetitive DNA sequences. This has demonstrated that a complex plant genome sequence can be assembled and characterized using these technologies without the availability of a physical reference. Additionally, we also report on primary factors contributing to genome size differences between pear and apple, both belonging to the subfamily Pomoideae; chromosomal evolution of Rosaceae; and genes controlling valuable traits of pear, including self-incompatibility, lignified stone cells in flesh of fruit (unique to pear), sugar, and aroma.

742 citations

Journal ArticleDOI
TL;DR: This study proposes a model for the divergence, dissemination, and independent domestication of Asian and European pears in which pear has eventually spread to western Asia, and then on to Europe, thus promoting outcrossing and accounting for pear genome diversity across the Eurasian continent.
Abstract: Pear (Pyrus) is a globally grown fruit, with thousands of cultivars in five domesticated species and dozens of wild species. However, little is known about the evolutionary history of these pear species and what has contributed to the distinct phenotypic traits between Asian pears and European pears. We report the genome resequencing of 113 pear accessions from worldwide collections, representing both cultivated and wild pear species. Based on 18,302,883 identified SNPs, we conduct phylogenetics, population structure, gene flow, and selective sweep analyses. Furthermore, we propose a model for the divergence, dissemination, and independent domestication of Asian and European pears in which pear, after originating in southwest China and then being disseminated throughout central Asia, has eventually spread to western Asia, and then on to Europe. We find evidence for rapid evolution and balancing selection for S-RNase genes that have contributed to the maintenance of self-incompatibility, thus promoting outcrossing and accounting for pear genome diversity across the Eurasian continent. In addition, separate selective sweep signatures between Asian pears and European pears, combined with co-localized QTLs and differentially expressed genes, underline distinct phenotypic fruit traits, including flesh texture, sugar, acidity, aroma, and stone cells. This study provides further clarification of the evolutionary history of pear along with independent domestication of Asian and European pears. Furthermore, it provides substantive and valuable genomic resources that will significantly advance pear improvement and molecular breeding efforts.

115 citations

Journal ArticleDOI
TL;DR: It is shown that microRNA (miR) miR397a regulates fruit cell lignification by inhibiting laccase (LAC) genes that encode key lignin biosynthesis enzymes.
Abstract: Lignified stone cells substantially reduce fruit quality. Therefore, it is desirable to inhibit stone cell development using genetic technologies. However, the molecular mechanisms regulating lignification are poorly understood in fruit stone cells. In this study, we have shown that microRNA (miR) miR397a regulates fruit cell lignification by inhibiting laccase (LAC) genes that encode key lignin biosynthesis enzymes. Transient overexpression of PbrmiR397a, which is the miR397a of Chinese pear (Pyrus bretschneideri), and simultaneous silencing of three LAC genes reduced the lignin content and stone cell number in pear fruit. A single nucleotide polymorphism (SNP) identified in the promoter of the PbrmiR397a gene was found to associate with low levels of fruit lignin, after analysis of the genome sequences of sixty pear varieties. This SNP created a TCA element that responded to salicylic acid to induce gene expression as confirmed using a cell-based assay system. Furthermore, stable overexpression of PbrmiR397a in transgenic tobacco plants reduced the expression of target LAC genes and decreased the content of lignin but did not change the ratio of syringyl- and guaiacyl-lignin monomers. Consistent with reduction in lignin content, the transgenic plants showed fewer numbers of vessel elements and thinner secondary walls in the remaining elements compared to wild-type control plants. This study has advanced our understanding of the regulation of lignin biosynthesis and provided useful molecular genetic information for improving pear fruit quality.

106 citations

Journal ArticleDOI
TL;DR: The expression patterns of genes encoding enzymes indicated that ANS and UFGT were decisive genes for anthocyanin biosynthesis for red-skinned pear, and their different expressions led to the coloration differences between occidental and oriental pears.
Abstract: Key message This research reveals the different expression patterns of anthocyanin biosynthesis enzyme genes and transcription factors in six red-skinned pear cultivars with different genetic backgrounds.

57 citations

Journal ArticleDOI
TL;DR: The transcriptomes of five pear cultivars were sequenced at seven key fruit developmental stages, from fruit setting to maturation and fruit senescence after harvesting, and co-expression analysis revealed that several ethylene synthesis genes and polyphenoloxidase-related genes interacted with each other directly, and an indirect relationship was reflected between ethylenehesis genes and ethylene response genes.
Abstract: The transcriptomes of five pear cultivars, 'Hosui' (P. pyrifolia), 'Yali' (P. bretschneideri), 'Kuerlexiangli' (P. sinkiangensis), 'Nanguoli' (P. ussuriensis), and 'Starkrimson' (P. communis) were sequenced at seven key fruit developmental stages, from fruit setting to maturation and fruit senescence after harvesting. In total, 33,136 genes that could be mapped by reads, were analyzed. Most gene expression cluster models showed a steadily decreasing trend. Gene expression patterns had obvious differences according to maturity type, that is, post-ripening cultivars were still vigorous at maturity, and showed a higher proportion of up-regulated genes; non post-ripening cultivars had a gradually decreasing tendency during fruit maturation. Meanwhile, differentially expressed genes related to fruit quality and development, such as stone cells, sugar, acid and hormones, were identified. Co-expression analysis revealed that several ethylene synthesis genes and polyphenoloxidase-related genes interacted with each other directly, and an indirect relationship was reflected between ethylene synthesis genes and ethylene response genes. In addition, the highly diverse SNPs represented the great differences between oriental and occidental pears. Understanding how RNA-seq based gene-expression patterns and differential gene expression contribute to fruit quality allows us to build models for gene-expression for fruit development of Pyrus species.

50 citations


Cited by
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Journal Article
Fumio Tajima1
30 Oct 1989-Genomics
TL;DR: It is suggested that the natural selection against large insertion/deletion is so weak that a large amount of variation is maintained in a population.

11,521 citations

01 Jan 2011
TL;DR: The sheer volume and scope of data posed by this flood of data pose a significant challenge to the development of efficient and intuitive visualization tools able to scale to very large data sets and to flexibly integrate multiple data types, including clinical data.
Abstract: Rapid improvements in sequencing and array-based platforms are resulting in a flood of diverse genome-wide data, including data from exome and whole-genome sequencing, epigenetic surveys, expression profiling of coding and noncoding RNAs, single nucleotide polymorphism (SNP) and copy number profiling, and functional assays. Analysis of these large, diverse data sets holds the promise of a more comprehensive understanding of the genome and its relation to human disease. Experienced and knowledgeable human review is an essential component of this process, complementing computational approaches. This calls for efficient and intuitive visualization tools able to scale to very large data sets and to flexibly integrate multiple data types, including clinical data. However, the sheer volume and scope of data pose a significant challenge to the development of such tools.

2,187 citations

Journal ArticleDOI
TL;DR: Platanus provides a novel and efficient approach for the assembly of gigabase-sized highly heterozygous genomes and is an attractive alternative to the existing assemblers designed for genomes of lower heterozygosity.
Abstract: Although many de novo genome assembly projects have recently been conducted using high-throughput sequencers, assembling highly heterozygous diploid genomes is a substantial challenge due to the increased complexity of the de Bruijn graph structure predominantly used. To address the increasing demand for sequencing of nonmodel and/or wild-type samples, in most cases inbred lines or fosmid-based hierarchical sequencing methods are used to overcome such problems. However, these methods are costly and time consuming, forfeiting the advantages of massive parallel sequencing. Here, we describe a novel de novo assembler, Platanus, that can effectively manage high-throughput data from heterozygous samples. Platanus assembles DNA fragments (reads) into contigs by constructing de Bruijn graphs with automatically optimized k-mer sizes followed by the scaffolding of contigs based on paired-end information. The complicated graph structures that result from the heterozygosity are simplified during not only the contig assembly step but also the scaffolding step. We evaluated the assembly results on eukaryotic samples with various levels of heterozygosity. Compared with other assemblers, Platanus yields assembly results that have a larger scaffold NG50 length without any accompanying loss of accuracy in both simulated and real data. In addition, Platanus recorded the largest scaffold NG50 values for two of the three low-heterozygosity species used in the de novo assembly contest, Assemblathon 2. Platanus therefore provides a novel and efficient approach for the assembly of gigabase-sized highly heterozygous genomes and is an attractive alternative to the existing assemblers designed for genomes of lower heterozygosity.

924 citations

Journal ArticleDOI
TL;DR: A draft genome sequence of Brassica oleracea is described, comparing it with that of its sister species B. rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks.
Abstract: Polyploidization has provided much genetic variation for plant adaptive evolution, but the mechanisms by which the molecular evolution of polyploid genomes establishes genetic architecture underlying species differentiation are unclear Brassica is an ideal model to increase knowledge of polyploid evolution Here we describe a draft genome sequence of Brassica oleracea, comparing it with that of its sister species B rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks, asymmetrical amplification of transposable elements, differential gene co-retention for specific pathways and variation in gene expression, including alternative splicing, among a large number of paralogous and orthologous genes Genes related to the production of anticancer phytochemicals and morphological variations illustrate consequences of genome duplication and gene divergence, imparting biochemical and morphological variation to B oleracea This study provides insights into Brassica genome evolution and will underpin research into the many important crops in this genus

884 citations

05 Mar 2001
TL;DR: It is indicated that lignin and cellulose deposition could be regulated in a compensatory fashion, which may contribute to metabolic flexibility and a growth advantage to sustain the long-term structural integrity of woody perennials.
Abstract: Because lignin limits the use of wood for fiber, chemical, and energy production, strategies for its downregulation are of considerable interest. We have produced transgenic aspen (Populus tremuloides Michx.) trees in which expression of a lignin biosynthetic pathway gene Pt4CL1 encoding 4-coumarate:coenzyme A ligase (4CL) has been downregulated by antisense inhibition. Trees with suppressed Pt4CL1 expression exhibited up to a 45% reduction of lignin, but this was compensated for by a 15% increase in cellulose. As a result, the total lignin–cellulose mass remained essentially unchanged. Leaf, root, and stem growth were substantially enhanced, and structural integrity was maintained both at the cellular and whole-plant levels in the transgenic lines. Our results indicate that lignin and cellulose deposition could be regulated in a compensatory fashion, which may contribute to metabolic flexibility and a growth advantage to sustain the long-term structural integrity of woody perennials.

717 citations