Project description:affy_hexaploid_wheat - hexa - Changes upon polyploidization in hexaploid wheat - transcriptomic changes in synthetic hexaploid derived from a cross between tetraploid and natural diploid. Study aims to understand regulation of gene expression in synthetic and natural wheat allohexaploids (Triticum aestivum), that combines the AB genome of T. turgidum and the D genome of Aegilops tauschii; and which we have recently characterized as genetically stable. We conducted a comprehensive genome-wide analysis of gene expression that allowed us to compare the effect of variability of the D genome progenitor, the trans-generation stability as well as comparison to natural wheat allohexaploid. We used the Affymetrix GeneChip® Wheat Genome Array, on which 55,049 transcripts are represented. Additive expression was shown to represent majority of expression regulation in the synthetic allohexaploids, where expression for more than 93% of transcripts was equal to the one evaluated from equal mixture of parental RNA. This leaves ~2000 (~7%) transcripts, which expression was non-additive. No global gene expression bias or dominance towards any of the progenitor genomes was observed whereas high trans-generational stability and low effect of the D genome progenitor variability were revealed. Our study suggests that gene expression regulation in wheat allohexaploids is early established upon allohexaploidization and highly conserved over generations, as demonstrated by the high similarity of expression with natural wheat allohexaploids. Keywords: genotype and ecotype comparison
Project description:BackgroundDNA methylation is an important mechanism of epigenetic gene expression control that can be passed between generations. Here, we use sodium bisulfite treatment and targeted gene enrichment to study genome-wide methylation across the three sub-genomes of allohexaploid wheat.ResultsWhile the majority of methylation is conserved across all three genomes we demonstrate that differential methylation exists between the sub-genomes in approximately equal proportions. We correlate sub-genome-specific promoter methylation with decreased expression levels and show that altered growing temperature has a small effect on methylation state, identifying a small but functionally relevant set of methylated genes. Finally, we demonstrate long-term methylation maintenance using a comparison between the D sub-genome of hexaploid wheat and its progenitor Aegilops tauschii.ConclusionsWe show that tri-genome methylation is highly conserved with the diploid wheat progenitor while sub-genome-specific methylation shows more variation.
Project description:affy_hexaploid_wheat - hexa - Changes upon polyploidization in hexaploid wheat - transcriptomic changes in synthetic hexaploid derived from a cross between tetraploid and natural diploid. Study aims to understand regulation of gene expression in synthetic and natural wheat allohexaploids (Triticum aestivum), that combines the AB genome of T. turgidum and the D genome of Aegilops tauschii; and which we have recently characterized as genetically stable. We conducted a comprehensive genome-wide analysis of gene expression that allowed us to compare the effect of variability of the D genome progenitor, the trans-generation stability as well as comparison to natural wheat allohexaploid. We used the Affymetrix GeneChip® Wheat Genome Array, on which 55,049 transcripts are represented. Additive expression was shown to represent majority of expression regulation in the synthetic allohexaploids, where expression for more than 93% of transcripts was equal to the one evaluated from equal mixture of parental RNA. This leaves ~2000 (~7%) transcripts, which expression was non-additive. No global gene expression bias or dominance towards any of the progenitor genomes was observed whereas high trans-generational stability and low effect of the D genome progenitor variability were revealed. Our study suggests that gene expression regulation in wheat allohexaploids is early established upon allohexaploidization and highly conserved over generations, as demonstrated by the high similarity of expression with natural wheat allohexaploids. Keywords: genotype and ecotype comparison 18 arrays - wheat
Project description:Many crop species have complex genomes, making the conventional pathway to associating molecular markers with trait variation, which includes genome sequencing, both expensive and time-consuming. We used a streamlined approach to rapidly develop a genomics platform for hexaploid wheat based on the inferred order of expressed sequences. This involved assembly of the transcriptomes for the progenitor genomes of bread wheat, the development of a genetic linkage map comprising 9495 mapped transcriptome-based SNP markers, use of this map to rearrange the genome sequence of Brachypodium distachyon into pseudomolecules representative of the genome organization of wheat and sequence similarity-based mapping onto this resource of the transcriptome assemblies. To demonstrate that this approximation of gene order in wheat is appropriate to underpin association genetics analysis, we undertook Associative Transcriptomics for straw biomass traits, identifying associations and even candidate genes for height, weight and width.
Project description:Gene expression levels of newly synthetic triploid wheat (ABD), its chromosome-doubled hexaploid (AABBDD), stable synthetic hexaploid (AABBDD), and their parents, Triticum turgidum (accession KU124, AABB) and Aegilops tauschii (accession KU2074, DD) were compared to understand genome-wide change of gene expressions during the course of amphidiploidization and genome stabilization. Stable synthetic hexaploid which were maintained through self-pollinations for 13 generations using the same combinations of the parents for production of synthetic common wheat.
Project description:Plants of two non-restorer varieties of hexaploid winter wheat (Astoria, Grana) and two restorers ones (Patres and Primépi) were used to identify effective Rf (fertility restorer) genes by next generation sequencing on whole transcriptomes (RNA-seq).
Project description:Bread wheat (Triticum aestivum) has a large, complex and hexaploid genome consisting of A, B and D homoeologous chromosome sets. Therefore each wheat gene potentially exists as a trio of A, B and D homoeoalleles, each of which may contribute differentially to wheat phenotypes. We describe a novel approach combining wheat cytogenetic resources (chromosome substitution ânullisomic-tetrasomicâ lines) with next generation deep sequencing of gene transcripts (RNA-seq), to directly and accurately identify homoeologue-specific single nucleotide variants and quantify the relative homoeoallelic contribution to gene expression. We obtained mRNA-Seq datasets from non-normalized cDNA libraries created from shoot and root tissues of the euploid bread wheat cultivar Chinese Spring, from which the nullitetra lines are derived, from complete sets of chromosome 1 and 5 nullitetras, and from extant relatives of the diploid A (Triticum urartu) and D (Aegilops tauschii) genome donors, herein referred to as A and D genome diploids