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Morimoto T, Narazaki R, Okabe H, Zhang L, Nishimura K, Itai A. Introduction of a diverse genetic background of Pyrus into Malus through intergeneric hybridization. Mol Genet Genomics 2024; 299:21. [PMID: 38429502 DOI: 10.1007/s00438-024-02131-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 02/21/2024] [Indexed: 03/03/2024]
Abstract
Wide hybridizations across species and genera have been employed to enhance agriculturally important traits in crops. Within the tribe Maleae of the Rosaceae family, different genera and species exhibit several traits useful for increasing diversity and gene pool through hybridization. This study aimed to develop and characterize intergeneric hybrid individuals between Malus and Pyrus. Through seed germination, shoot multiplication, and rooting in vitro, acclimatized seedlings showing vegetative growth on their own roots were obtained from crosses of Malus × domestica pollinated by Pyrus communis, P. bretschneideri, and the Pyrus interspecific hybrid (P. communis × P. pyrifolia). Comparative analysis of leaf morphology, flow cytometry, and molecular genotyping confirmed the hybrid status of the individuals. Genome-wide genotyping revealed that all the hybrid individuals inherited genomic fragments symmetrically from the Malus and Pyrus parents. To the best of our knowledge, this is the first report on the development of intergeneric hybrid seedlings between Malus × domestica and P. bretschneideri. Furthermore, the Pyrus interspecific hybrid individual served as a bridge plant for introducing the genetic background of P. pyrifolia into Malus × domestica. The results of this study provided a crucial foundation for breeding through intergeneric hybridization between Malus and Pyrus, facilitating the incorporation of valuable traits from diverse gene pools.
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Affiliation(s)
- Takuya Morimoto
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.
| | - Ryuya Narazaki
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Hiroaki Okabe
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Lumin Zhang
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
- Institute of Tropical Eco-agriculture, Yunnan Academy of Agricultural Sciences, Yunnan, China
| | - Kazusa Nishimura
- Graduate School of Environmental, Natural Science and Technology, Okayama University, Life, Okayama, Japan
| | - Akihiro Itai
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
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Tezuka T, Nagai S, Matsuo C, Okamori T, Iizuka T, Marubashi W. Genetic Cause of Hybrid Lethality Observed in Reciprocal Interspecific Crosses between Nicotiana simulans and N. tabacum. Int J Mol Sci 2024; 25:1226. [PMID: 38279225 PMCID: PMC10817076 DOI: 10.3390/ijms25021226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/17/2024] [Accepted: 01/17/2024] [Indexed: 01/28/2024] Open
Abstract
Hybrid lethality, a type of postzygotic reproductive isolation, is an obstacle to wide hybridization breeding. Here, we report the hybrid lethality that was observed in crosses between the cultivated tobacco, Nicotiana tabacum (section Nicotiana), and the wild tobacco species, Nicotiana simulans (section Suaveolentes). Reciprocal hybrid seedlings were inviable at 28 °C, and the lethality was characterized by browning of the hypocotyl and roots, suggesting that hybrid lethality is due to the interaction of nuclear genomes derived from each parental species, and not to a cytoplasmic effect. Hybrid lethality was temperature-sensitive and suppressed at 36 °C. However, when hybrid seedlings cultured at 36 °C were transferred to 28 °C, all of them showed hybrid lethality. After crossing between an N. tabacum monosomic line missing one copy of the Q chromosome and N. simulans, hybrid seedlings with or without the Q chromosome were inviable and viable, respectively. These results indicated that gene(s) on the Q chromosome are responsible for hybrid lethality and also suggested that N. simulans has the same allele at the Hybrid Lethality A1 (HLA1) locus responsible for hybrid lethality as other species in the section Suaveolentes. Haplotype analysis around the HLA1 locus suggested that there are at least six and two haplotypes containing Hla1-1 and hla1-2 alleles, respectively, in the section Suaveolentes.
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Affiliation(s)
- Takahiro Tezuka
- Graduate School of Agriculture, Osaka Metropolitan University, Sakai 599-8531, Osaka, Japan;
- Education and Research Field, School of Agriculture, Osaka Metropolitan University, Sakai 599-8531, Osaka, Japan
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Osaka, Japan;
- School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Osaka, Japan
| | - Shota Nagai
- Graduate School of Agriculture, Osaka Metropolitan University, Sakai 599-8531, Osaka, Japan;
| | - Chihiro Matsuo
- School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Osaka, Japan
| | - Toshiaki Okamori
- School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Osaka, Japan
| | - Takahiro Iizuka
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Osaka, Japan;
| | - Wataru Marubashi
- School of Agriculture, Meiji University, Kawasaki 214-8571, Kanagawa, Japan;
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Mino M, Tezuka T, Shomura S. The hybrid lethality of interspecific F 1 hybrids of Nicotiana: a clue to understanding hybrid inviability-a major obstacle to wide hybridization and introgression breeding of plants. MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2022; 42:10. [PMID: 37309322 PMCID: PMC10248639 DOI: 10.1007/s11032-022-01279-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
Reproductive isolation poses a major obstacle to wide hybridization and introgression breeding of plants. Hybrid inviability in the postzygotic isolation barrier inevitably reduces hybrid fitness, consequently causing hindrances in the establishment of novel genotypes from the hybrids among genetically divergent parents. The idea that the plant immune system is involved in the hybrid problem is applicable to the intra- and/or interspecific hybrids of many different taxa. The lethality characteristics and expression profile of genes associated with the hypersensitive response of the hybrids, along with the suppression of causative genes, support the deleterious epistatic interaction of parental NB-LRR protein genes, resulting in aberrant hyper-immunity reactions in the hybrid. Moreover, the cellular, physiological, and biochemical reactions observed in hybrid cells also corroborate this hypothesis. However, the difference in genetic backgrounds of the respective hybrids may contribute to variations in lethality phenotypes among the parental species combinations. The mixed state in parental components of the chaperone complex (HSP90-SGT1-RAR1) in the hybrid may also affect the hybrid inviability. This review article discusses the facts and hypothesis regarding hybrid inviability, alongside the findings of studies on the hybrid lethality of interspecific hybrids of the genus Nicotiana. A possible solution for averting the hybrid problem has also been scrutinized with the aim of improving the wide hybridization and introgression breeding program in plants.
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Affiliation(s)
- Masanobu Mino
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, 606-8522 Japan
- Present Address: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku Sakai, Osaka, 599-8531 Japan
| | - Takahiro Tezuka
- Present Address: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku Sakai, Osaka, 599-8531 Japan
| | - Sachiko Shomura
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, 606-8522 Japan
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Morimoto T, Kitamura Y, Numaguchi K, Itai A. Characterization of transcriptomic response in ovules derived from inter-subgeneric hybridization in Prunus (Rosaceae) species. PLANT REPRODUCTION 2021; 34:255-266. [PMID: 34165636 DOI: 10.1007/s00497-021-00423-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 06/18/2021] [Indexed: 06/13/2023]
Abstract
Characterization of hybrid seed failure in Prunus provides insight into conserved or lineage-specific hybrid incompatibility mechanisms in plant species. Postzygotic hybrid incompatibility resulting from a cross between different species involves complex mechanisms occurring at various developmental stages. Embryo arrest, followed by seed abortion, is the first stage of such incompatibility reactions and inhibits hybrid seed development. In Prunus, a rosaceous woody species, some interspecific crosses result in fruit drop during the early stage of fruit development, in which inferior seed development may be accounted for the observed hybrid incompatibility. In this study, we investigated ovule development and the transcriptomes of developing ovules in inter-subgeneric crosses of Prunus. We conducted a cross of Prunus mume (subgenus Prunus), pollinated by P. persica (subgenus Amygdalus), and found that ovule and seed coat degeneration occurs before fruit drop. Transcriptome analysis identified differentially expressed genes enriched in several GO pathways, including organelle development, stimulus response, and signaling. Among these pathways, the organelle-related genes were actively regulated during ovule development, as they showed higher expression in the early stage of interspecific crosses and declined in the later stage, suggesting that the differential regulation of organelle function may induce the degeneration of hybrid ovules. Additionally, genes related to ovule and seed coat development, such as genes encoding AGL-like and auxin response, were differentially regulated in Prunus interspecific crosses. Our results provide histological and molecular information on hybrid seed abortion in Prunus that could be utilized to develop new hybrid crops. Additionally, we compared and discussed transcriptome responses to hybrid seed failure in Prunus and other plant species, which provides insight into conserved or lineage-specific hybrid incompatibility mechanisms in some plant species.
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Affiliation(s)
- Takuya Morimoto
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 619-0244, Japan.
| | - Yuto Kitamura
- Japanese Apricot Laboratory, Wakayama Fruit Tree Experiment Station, Wakayama, 645-0021, Japan
- Faculty of Agriculture, Setsunan University, Osaka, 573-0101, Japan
| | - Koji Numaguchi
- Japanese Apricot Laboratory, Wakayama Fruit Tree Experiment Station, Wakayama, 645-0021, Japan
| | - Akihiro Itai
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 619-0244, Japan
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Wan WL, Kim ST, Castel B, Charoennit N, Chae E. Genetics of autoimmunity in plants: an evolutionary genetics perspective. THE NEW PHYTOLOGIST 2021; 229:1215-1233. [PMID: 32970825 DOI: 10.1111/nph.16947] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/12/2020] [Indexed: 05/14/2023]
Abstract
Autoimmunity in plants has been found in numerous hybrids as a form of hybrid necrosis and mutant panels. Uncontrolled cell death is a main cellular outcome of autoimmunity, which negatively impacts growth. Its occurrence highlights the vulnerable nature of the plant immune system. Genetic investigation of autoimmunity in hybrid plants revealed that extreme variation in the immune receptor repertoire is a major contributor, reflecting an evolutionary conundrum that plants face in nature. In this review, we discuss natural variation in the plant immune system and its contribution to fitness. The value of autoimmunity genetics lies in its ability to identify combinations of a natural immune receptor and its partner that are predisposed to triggering autoimmunity. The network of immune components for autoimmunity becomes instrumental in revealing mechanistic details of how immune receptors recognize cellular invasion and activate signaling. The list of autoimmunity-risk variants also allows us to infer evolutionary processes contributing to their maintenance in the natural population. Our approach to autoimmunity, which integrates mechanistic understanding and evolutionary genetics, has the potential to serve as a prognosis tool to optimize immunity in crops.
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Affiliation(s)
- Wei-Lin Wan
- Department of Biological Sciences, National University of Singapore, Singapore, 117558, Singapore
| | - Sang-Tae Kim
- Department of Life Sciences, The Catholic University of Korea, Bucheon, Gyeonggi-do, 14662, South Korea
| | - Baptiste Castel
- Department of Biological Sciences, National University of Singapore, Singapore, 117558, Singapore
| | - Nuri Charoennit
- Department of Biological Sciences, National University of Singapore, Singapore, 117558, Singapore
| | - Eunyoung Chae
- Department of Biological Sciences, National University of Singapore, Singapore, 117558, Singapore
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Xue H, Wang S, Yao JL, Deng CH, Wang L, Su Y, Zhang H, Zhou H, Sun M, Li X, Yang J. Chromosome level high-density integrated genetic maps improve the Pyrus bretschneideri 'DangshanSuli' v1.0 genome. BMC Genomics 2018; 19:833. [PMID: 30463521 PMCID: PMC6249763 DOI: 10.1186/s12864-018-5224-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 11/06/2018] [Indexed: 01/23/2023] Open
Abstract
Background Chromosomal level reference genomes provide a crucial foundation for genomics research such as genome-wide association studies (GWAS) and whole genome selection. The chromosomal-level sequences of both the European (Pyrus communis) and Chinese (P. bretschneideri) pear genomes have not been published in public databases so far. Results To anchor the scaffolds of P. bretschneideri ‘DangshanSuli’ (DS) v1.0 genome into pseudo-chromosomes, two genetic maps (MH and YM maps) were constructed using half sibling populations of Chinese pear crosses, ‘Mantianhong’ (MTH) × ‘Hongxiangsu’ (HXS) and ‘Yuluxiang’ (YLX) × MTH, from 345 and 162 seedlings, respectively, which were prepared for SNP discovery using genotyping-by-sequencing (GBS) technology. The MH and YM maps, each with 17 linkage groups (LGs), were constructed from 2606 and 2489 SNP markers and spanned 1847 and 1668 cM, respectively, with average marker intervals of 0.7. The two maps were further merged with a previously published genetic map (BD) based on the cross ‘Bayuehong’ (BYH) × ‘Dangshansuli’ (DS) to build a new integrated MH-YM-BD map. By using 7757 markers located on the integrated MH-YM-BD map, 898 scaffolds (400.57 Mb) of the DS v1.0 assembly were successfully anchored into 17 pseudo-chromosomes, accounting for 78.8% of the assembled genome size. About 88.31% of them (793 scaffolds) were directionally anchored with two or more markers on the pseudo-chromosomes. Furthermore, the errors in each pseudo-chromosome (especially 1, 5, 7 and 11) were manually corrected and pseudo-chromosomes 1, 5 and 7 were extended by adding 19, 12 and 14 scaffolds respectively in the newly constructed DS v1.1 genome. Synteny analyses revealed that the DS v1.1 genome had high collinearity with the apple genome, and the homologous fragments between pseudo-chromosomes were similar to those found in previous studies. Moreover, the red-skin trait of Asian pear was mapped to an identical locus as identified previously. Conclusions The accuracy of DS v1.1 genome was improved by using larger mapping populations and merged genetic map. With more than 400 MB anchored to 17 pseudo-chromosomes, the new DS v1.1 genome provides a critical tool that is essential for studies of pear genetics, genomics and molecular breeding. Electronic supplementary material The online version of this article (10.1186/s12864-018-5224-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Huabai Xue
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Key Laboratory of Fruit Breeding Technology of Ministry of Agriculture, Zhengzhou, 450009, China
| | - Suke Wang
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Key Laboratory of Fruit Breeding Technology of Ministry of Agriculture, Zhengzhou, 450009, China
| | - Jia-Long Yao
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Key Laboratory of Fruit Breeding Technology of Ministry of Agriculture, Zhengzhou, 450009, China.,The New Zealand Institute for Plant and Food Research Limited, Auckland, 1025, New Zealand
| | - Cecilia H Deng
- The New Zealand Institute for Plant and Food Research Limited, Auckland, 1025, New Zealand
| | - Long Wang
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Key Laboratory of Fruit Breeding Technology of Ministry of Agriculture, Zhengzhou, 450009, China
| | - Yanli Su
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Key Laboratory of Fruit Breeding Technology of Ministry of Agriculture, Zhengzhou, 450009, China
| | - Huirong Zhang
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Key Laboratory of Fruit Breeding Technology of Ministry of Agriculture, Zhengzhou, 450009, China
| | - Huangkai Zhou
- Guangzhou Gene Denovo Biotechnology Co., Ltd, Guangzhou, 510320, China
| | - Minshan Sun
- Guangzhou Gene Denovo Biotechnology Co., Ltd, Guangzhou, 510320, China
| | - Xiugen Li
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Key Laboratory of Fruit Breeding Technology of Ministry of Agriculture, Zhengzhou, 450009, China.
| | - Jian Yang
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Key Laboratory of Fruit Breeding Technology of Ministry of Agriculture, Zhengzhou, 450009, China.
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Ma N, Liu C, Li H, Wang J, Zhang B, Lin J, Chang Y. Genome-wide identification of lectin receptor kinases in pear: Functional characterization of the L-type LecRLK gene PbLRK138. Gene 2018; 661:11-21. [PMID: 29601951 DOI: 10.1016/j.gene.2018.03.077] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 03/13/2018] [Accepted: 03/26/2018] [Indexed: 12/31/2022]
Abstract
Lectin receptor-like kinases (LecRLKs) are membrane-bound receptors that are believed to be involved in biotic and abiotic stress responses. However, little is known about the LecRLK family in pear. In this study, a total of 172 LecRLK genes were first identified in the entire pear genome. The 172 LecRLKs were divided into three types (111 G-, 59 L- and two C-types) based on their structure and phylogenetic relationships. LecRLKs gene expressions were detected in different pear tissues including roots, stems, leaves, flowers and fruits, and the most of the 11 selected LecRLKs exhibited similar expression patterns. Furthermore, six selected LecRLKs were shown to be involved in salt stress response. Overexpression of PbLRK138, an L-type LecRLK, caused cell death and induced expression of defense-related genes in Nicotiana benthamiana. Two deletion mutants containing lectin or transmembrane and serine/threonine kinase domains did not trigger cell death. In addition, only the mutant with the transmembrane domain was localized to the plasma membrane.
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Affiliation(s)
- Na Ma
- Institute of Pomology, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Chunxiao Liu
- Institute of Pomology, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Hui Li
- Institute of Pomology, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Jinyan Wang
- Institute of Germplasm and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Baolong Zhang
- Institute of Germplasm and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Jing Lin
- Institute of Pomology, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Youhong Chang
- Institute of Pomology, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China.
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Li L, Deng CH, Knäbel M, Chagné D, Kumar S, Sun J, Zhang S, Wu J. Integrated high-density consensus genetic map of Pyrus and anchoring of the 'Bartlett' v1.0 (Pyrus communis) genome. DNA Res 2017; 24:289-301. [PMID: 28130382 PMCID: PMC5499846 DOI: 10.1093/dnares/dsw063] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 12/16/2016] [Indexed: 01/14/2023] Open
Abstract
Genetic maps are essential tools for pear genetics and genomics research. In this study, we first constructed an integrated simple sequence repeat (SSR) and single nucleotide polymorphism (SNP)-based consensus genetic map for pear based on common SSR markers between nine published maps. A total of 5,085 markers, including 1,232 SSRs and 3,853 SNPs, were localized on a consensus map spanning 3,266.0 cM in total, with an average marker interval of 0.64 cM, which represents the highest density consensus map of pear to date. Using three sets of high-density SNP-based genetic maps with European pear genetic backgrounds, we anchored a total of 291.5 Mb of the ‘Bartlett’ v1.0 (Pyrus communis L.) genome scaffolds into 17 pseudo-chromosomes. This accounted for 50.5% of the genome assembly, which was a great improvement on the 29.7% achieved originally. Intra-genome and inter-genome synteny analyses of the new ‘Bartlett’ v1.1 genome assembly with the Asian pear ‘Dangshansuli’ (Pyrus bretschneideri Rehd.) and apple (Malus × domestica Borkh.) genomes uncovered four new segmental duplication regions. The integrated high-density SSR and SNP-based consensus genetic map provided new insights into the genetic structure patterns of pear and assisted in the genome assembly of ‘Bartlett’ through further exploration of different pear genetic maps.
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Affiliation(s)
- Leiting Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Centre of Pear Engineering Technology Research, Nanjing Agricultural University, Nanjing, China
| | - Cecilia H Deng
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), New Zealand
| | - Mareike Knäbel
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), New Zealand
| | - David Chagné
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), New Zealand
| | - Satish Kumar
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research), New Zealand
| | - Jiangmei Sun
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Centre of Pear Engineering Technology Research, Nanjing Agricultural University, Nanjing, China
| | - Shaoling Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Centre of Pear Engineering Technology Research, Nanjing Agricultural University, Nanjing, China
| | - Jun Wu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Centre of Pear Engineering Technology Research, Nanjing Agricultural University, Nanjing, China
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Kumar S, Kirk C, Deng C, Wiedow C, Knaebel M, Brewer L. Genotyping-by-sequencing of pear ( Pyrus spp.) accessions unravels novel patterns of genetic diversity and selection footprints. HORTICULTURE RESEARCH 2017; 4:17015. [PMID: 28451438 PMCID: PMC5389204 DOI: 10.1038/hortres.2017.15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/22/2017] [Accepted: 02/22/2017] [Indexed: 05/06/2023]
Abstract
Understanding of genetic diversity and marker-trait relationships in pears (Pyrus spp.) forms an important part of gene conservation and cultivar breeding. Accessions of Asian and European pear species, and interspecific hybrids were planted in a common garden experiment. Genotyping-by-sequencing (GBS) was used to genotype 214 accessions, which were also phenotyped for fruit quality traits. A combination of selection scans and association analyses were used to identify signatures of selection. Patterns of genetic diversity, population structure and introgression were also investigated. About 15 000 high-quality SNP markers were identified from the GBS data, of which 25% and 11% harboured private alleles for European and Asian species, respectively. Bayesian clustering analysis suggested negligible gene flow, resulting in highly significant population differentiation (Fst=0.45) between Asian and European pears. Interspecific hybrids displayed an average of 55% and 45% introgression from their Asian and European ancestors, respectively. Phenotypic (firmness, acidity, shape and so on) variation between accessions was significantly associated with genetic differentiation. Allele frequencies at large-effect SNP loci were significantly different between genetic groups, suggesting footprints of directional selection. Selection scan analyses identified over 20 outlier SNP loci with substantial statistical support, likely to be subject to directional selection or closely linked to loci under selection.
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Affiliation(s)
- Satish Kumar
- The New Zealand Institute for Plant & Food Research Limited, Hawke’s Bay Research Centre, Havelock North, New Zealand
- ()
| | - Chris Kirk
- Palmerston North Research Centre, Palmerston North, New Zealand
| | - Cecilia Deng
- Mount Albert Research Centre, Auckland, New Zealand
| | - Claudia Wiedow
- Palmerston North Research Centre, Palmerston North, New Zealand
| | - Mareike Knaebel
- Palmerston North Research Centre, Palmerston North, New Zealand
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