Molecular cytogenetic and genomic analyses reveal new insights into the origin of the wheat B genome

Zhang, Wei; Zhang, Mingyi; Zhu, Xiaoming; Cao, Yiyi; Sun, Qing; Ma, Guojia; Chao, Shiaoman; Cheng, Yan; Xu, Steven S.; Cai, Xiwen

doi:10.1007/s00122-017-3007-0

Cited by 23 publications

(17 citation statements)

References 44 publications

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“…Our results and the previous reports consistently indicate that the B genome of tetraploid and hexaploid wheat have significantly higher genetic diversity than the A and D genomes [ 36 – 39 ]. It appears that the wheat B genome had undergone a more divergent evolutionary process than the A and D genomes [ 43 ]. In other words, the integrity of the A and D genomes have been well maintained over the evolutionary process, but not quite well for the B genome.…”

Section: Discussionmentioning

confidence: 99%

Cloning and characterization of the homoeologous genes for the Rec8-like meiotic cohesin in polyploid wheat

Zhang

Liu

et al. 2018

BMC Plant Biol

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BackgroundMeiosis is a specialized cell division critical for gamete production in the sexual reproduction of eukaryotes. It ensures genome integrity and generates genetic variability as well. The Rec8-like cohesin is a cohesion protein essential for orderly chromosome segregation in meiotic cell division. The Rec8-like genes and cohesins have been cloned and characterized in diploid models, but not in polyploids. The present study aimed to clone the homoeologous genes (homoeoalleles) for Rec8-like cohesin in polyploid wheat, an important food crop for humans, and to characterize their structure and function under a polyploid condition.ResultsWe cloned two Rec8-like homoeoalleles from tetraploid wheat (TtRec8-A1 and TtRec8-B1) and one from hexaploid wheat (TaRec8-D1), and performed expression and functional analyses of the homoeoalleles. Also, we identified other two Rec8 homoeoalleles in hexaploid wheat (TaRec8-A1 and TaRec8-B1) and the one in Aegilops tauschii (AetRec8-D1) by referencing the DNA sequences of the Rec8 homoeoalleles cloned in this study. The coding DNA sequences (CDS) of these six Rec8 homoeoalleles are all 1,827 bp in length, encoding 608 amino acids. They differed from each other primarily in introns although single nucleotide polymorphisms were detected in CDS. Substantial difference was observed between the homoeoalleles from the subgenome B (TtRec8-B1 and TaRec8-B1) and those from the subgenomes A and D (TtRec8-A1, TaRec8-A1, and TaRec8-D1). TtRec8-A1 expressed dominantly over TtRec8-B1, but comparably to TaRec8-D1, in polyploid wheat. In addition, we developed the antibody against wheat Rec8 and used the antibody to detect Rec8 cohesin in the Western blotting and subcellular localization analyses.ConclusionsThe Rec8 homoeoalleles from the subgenomes A and D are transcriptionally more active than the one from the subgenome B in polyploid wheat. The structural variation and differential expression of the Rec8 homoeoalleles indicate a unique cross-genome coordination of the homoeologous genes in polyploid wheat, and imply the distinction of the wheat subgenome B from the subgenomes A and D in the origin and evolution.Electronic supplementary materialThe online version of this article (10.1186/s12870-018-1442-y) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Cloning and characterization of the homoeologous genes for the Rec8-like meiotic cohesin in polyploid wheat

Zhang

Liu

et al. 2018

BMC Plant Biol

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“…The first hybridization event occurred 0.36 to 0.50 million years ago and produced a tetraploid species, Triticum turgidum (AABB) [24][25][26][27]. This hybridization involved Triticum urartu (donor of the AA genome) and an unknown species related to Aegilops speltoides (BB genome) [28]. Indeed Ae.…”

Section: Introductionmentioning

confidence: 99%

Wheat chromatin architecture is organized in genome territories and transcription factories

et al. 2020

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Background: Polyploidy is ubiquitous in eukaryotic plant and fungal lineages, and it leads to the coexistence of several copies of similar or related genomes in one nucleus. In plants, polyploidy is considered a major factor in successful domestication. However, polyploidy challenges chromosome folding architecture in the nucleus to establish functional structures. Results: We examine the hexaploid wheat nuclear architecture by integrating RNA-seq, ChIP-seq, ATAC-seq, Hi-C, and Hi-ChIP data. Our results highlight the presence of three levels of large-scale spatial organization: the arrangement into genome territories, the diametrical separation between facultative and constitutive heterochromatin, and the organization of RNA polymerase II around transcription factories. We demonstrate the micro-compartmentalization of transcriptionally active genes determined by physical interactions between genes with specific euchromatic histone modifications. Both intra-and interchromosomal RNA polymerase-associated contacts involve multiple genes displaying similar expression levels. Conclusions: Our results provide new insights into the physical chromosome organization of a polyploid genome, as well as on the relationship between epigenetic marks and chromosome conformation to determine a 3D spatial organization of gene expression, a key factor governing gene transcription in polyploids.

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“…squarrosa L.) (Kihara, 1946; McFadden and Sears, 1946), and the B genome was derived from a closely related species to Ae. speltoides Tausch (Riley et al, 1958; Sasanuma et al, 1996; Petersen et al, 2006; Kilian et al, 2007; Zhang W. et al, 2018) which has the S genome. Aegilops species are distributed from Europe to western China in a species-specific manner (van Slageren, 1994), adapted to many different climatic zones including drought/heat environments, different disease hot spots and nutrient-poor areas.…”

Section: Introductionmentioning

confidence: 99%

An Update of Recent Use of Aegilops Species in Wheat Breeding

Kishii

2019

Front. Plant Sci.

121

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Aegilops species have significantly contributed to wheat breeding despite the difficulties involved in the handling of wild species, such as crossability and incompatibility. A number of biotic resistance genes have been identified and incorporated into wheat varieties from Aegilops species, and this genus is also contributing toward improvement of complex traits such as yield and abiotic tolerance for drought and heat. The D genome diploid species of Aegilops tauschii has been utilized most often in wheat breeding programs. Other Aegilops species are more difficult to utilize in the breeding because of lower meiotic recombination frequencies; generally they can be utilized only after extensive and time-consuming procedures in the form of translocation/introgression lines. After the emergence of Ug99 stem rust and wheat blast threats, Aegilops species gathered more attention as a form of new resistance sources. This article aims to update recent progress on Aegilops species, as well as to cover new topics around their use in wheat breeding.

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Molecular cytogenetic and genomic analyses reveal new insights into the origin of the wheat B genome

Cited by 23 publications

References 44 publications

Cloning and characterization of the homoeologous genes for the Rec8-like meiotic cohesin in polyploid wheat

Cloning and characterization of the homoeologous genes for the Rec8-like meiotic cohesin in polyploid wheat

Wheat chromatin architecture is organized in genome territories and transcription factories

An Update of Recent Use of Aegilops Species in Wheat Breeding

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