Project description:We have employed whole genome microarray expression profiling as a discovery platform to identify genes to alter the transcript accumulation levels in grass-clump dwarf lines, which are synthetic hexaploid lines from triploid hybrids crossed between tetraploid wheat (Triticum turgidum ssp. durum cv. Langdon or T. turgidum ssp. carthlicum) and diploid wheat progenitor Aegilops tauschii (KU2025). No up-regulation of defense-related genes was observed under the normal temperature, and down-regulation of wheat APETALA1-like MADS-box genes, considered to act as flowering promoters, was found in the grass-clump dwarf lines. Together with small RNA sequencing analysis of the grass-clump dwarf line, unusual expression of the miR156/SPLs module could explain the grass-clump dwarf phenotype.
Project description:We have employed whole genome microarray expression profiling as a discovery platform to identify genes to alter the transcript accumulation levels in grass-clump dwarf lines, which are synthetic hexaploid lines from triploid hybrids crossed between tetraploid wheat (Triticum turgidum ssp. durum cv. Langdon or T. turgidum ssp. carthlicum) and diploid wheat progenitor Aegilops tauschii (KU2025). No up-regulation of defense-related genes was observed under the normal temperature, and down-regulation of wheat APETALA1-like MADS-box genes, considered to act as flowering promoters, was found in the grass-clump dwarf lines. Together with small RNA sequencing analysis of the grass-clump dwarf line, unusual expression of the miR156/SPLs module could explain the grass-clump dwarf phenotype. Expression patterns were compared between the three synthetic hexaploid lines showing the wild-type phenotype (as a reference) and grass-clump dwarf. Total RNA samples were isolated from crown tissues of the plants grown at 24°C under long day (18-h light and 6-h dark) condition for 8 weeks. Two independent experiments were conducted in each exprement.
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
Project description:Aegilops tauschii is the donor of the wheat D subgenome and an important genetic resource for wheat. The assembly of Ae. tauschii acc. AL8/78 reference genome sequence Aet v4.0 was therefore an important milestone for wheat biology and breeding. The combination of the > 4.2 Gb size of the Ae. tauschii genome and > 84% of recently evolved repeated sequences make sequencing this genome challenging. Here, we report further advances in the development of the Ae. tauschii acc. AL8/78 genome sequence. Two new genome-wide optical maps were constructed and employed in the revision of pseudomolecules and estimations of gap lengths. Gaps were closed with contigs of single-molecule Pacific Biosciences reads. The number of gaps in Aet v5.0 decreased by 38,899 compared to Aet v4.0. Transposable elements and protein-coding genes were reannotated. The number of high-confidence genes was reduced from 38,886 in Aet v4.0 to 32,980 in Aet v5.0. A nonredundant set of 478 biologically important genes including many of known function in wheat was manually annotated. Sixty-one microRNA precursor and 60 phasiRNA loci were discovered, annotated, and their expression was characterized. Also characterized was expression of other small RNAs, such as hc-siRNAs and tRFs. This upgraded genome sequence will facilitate the use of Ae. tauschii in wheat breeding and biological research. Aegilops tauschii is the donor of the wheat D subgenome and an important genetic resource for wheat. The assembly of Ae. tauschii acc. AL8/78 reference genome sequence Aet v4.0 was therefore an important milestone for wheat biology and breeding. The combination of the > 4.2 Gb size of the Ae. tauschii genome and > 84% of recently evolved repeated sequences make sequencing this genome challenging. Here, we report further advances in the development of the Ae. tauschii acc. AL8/78 genome sequence. Two new genome-wide optical maps were constructed and employed in the revision of pseudomolecules and estimations of gap lengths. Gaps were closed with contigs of single-molecule Pacific Biosciences reads. The number of gaps in Aet v5.0 decreased by 38,899 compared to Aet v4.0. Transposable elements and protein-coding genes were reannotated. The number of high-confidence genes was reduced from 38,886 in Aet v4.0 to 32,980 in Aet v5.0. A nonredundant set of 478 biologically important genes including many of known function in wheat was manually annotated. Sixty-one microRNA precursor and 60 phasiRNA loci were discovered, annotated, and their expression was characterized. Also characterized was expression of other small RNAs, such as hc-siRNAs and tRFs. This upgraded genome sequence will facilitate the use of Ae. tauschii in wheat breeding and biological research. Aegilops tauschii is the donor of the wheat D subgenome and an important genetic resource for wheat. The assembly of Ae. tauschii acc. AL8/78 reference genome sequence Aet v4.0 was therefore an important milestone for wheat biology and breeding. The combination of the > 4.2 Gb size of the Ae. tauschii genome and > 84% of recently evolved repeated sequences make sequencing this genome challenging. Here, we report further advances in the development of the Ae. tauschii acc. AL8/78 genome sequence. Two new genome-wide optical maps were constructed and employed in the revision of pseudomolecules and estimations of gap lengths. Gaps were closed with contigs of single-molecule Pacific Biosciences reads. The number of gaps in Aet v5.0 decreased by 38,899 compared to Aet v4.0. Transposable elements and protein-coding genes were reannotated. The number of high-confidence genes was reduced from 38,886 in Aet v4.0 to 32,980 in Aet v5.0. A nonredundant set of 478 biologically important genes including many of known function in wheat was manually annotated. Sixty-one microRNA precursor and 60 phasiRNA loci were discovered, annotated, and their expression was characterized. Also characterized was expression of other small RNAs, such as hc-siRNAs and tRFs. This upgraded genome sequence will facilitate the use of Ae. tauschii in wheat breeding and biological research.
Project description:We have employed whole genome microarray expression profiling as a discovery platform to identify genes to alter the transcript accumulation levels in two types of hybrid necrosis-showing plants; one was derived from interspecific crosses of two diploid wheat species Triticum monococcum ssp. aegilopoides and Triticum urartu, and another from intraspecific hybrids of common wheat. Of the up-regulated genes, defense-related and carbohyfrate metabosim-related genes were frequently found, whereas photosythesis-related genes down-regulated in the hybrid necrosis-showing plants. These observations strongly suggests that autoimmune responses might be triggered by Ne1-Ne2 interaction in common wheat and by Ned1-Ned2 interaction in the wild diploid wheat, and that genetically programmed cell death could be regarded as a hypersensitive response-like cell death similar to that observed in other wheat hybrid necrosis such as type III necrosis in the ABD wheat triploids crossed between tetraploid wheat and Aegilops tauschii.
Project description:We have employed whole genome microarray expression profiling as a discovery platform to identify genes to alter the transcript accumulation levels in a grass-clump dwarf line, which is a synthetic hexaploid line from triploid hybrids crossed between tetraploid wheat (Triticum turgidum ssp. durum cv. Langdon) and a diploid wheat relative Aegilops umbellulata (KU-4052). Up-regulation of metabolic and catabolic processes-related genes for cell wall-associated molecules was observed, and down-regulation of wheat APETALA1-like MADS-box genes, considered to act as flowering promoters, was found in the grass-clump dwarf line. Unusual expression of the branching-related SPLs and flowering time regulation-related MADS-box genes could explain the grass-clump dwarf phenotype.