Project description:Wild relatives of wheat are valuable sources for enhancing the genetic diversity of common wheat. Aegilops comosa, an annual diploid species with an MM genome constitution, possesses numerous agronomically valuable traits that can be exploited for wheat improvement. In this study, we report a chromosome-level genome assembly of Ae. comosa accession PI 551049, generated using PacBio high-fidelity (HiFi) reads and high-throughput chromosome conformation capture (Hi-C) data. The assembly spans 4.47 Gb, featuring a contig N50 of 23.59 Mb and a scaffold N50 of 619.05 Mb. A total of 39,057 gene models were annotated through a combination of homoeologous proteins, Iso-seq, and RNA-seq data. Comparative genome analysis revealed a terminal intrachromosomal translocation on chromosome 2 M in Ae. comosa. This newly constructed reference genome of Ae. comosa will serve as an important genomic resource for comparative genomic studies and the cloning of agriculturally important genes.
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 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.
Project description:We have employed whole genome microarray expression profiling as a discovery platform to identify genes to alter the transcript accumulation levels in SGA plants, which are triploid hybrids crossed between tetraploid wheat and a diploid wheat relative Aegilops umbellulata. Of the up-regulated genes, cell death and carboxy-lyase activity-related genes were the most frequently found in crown tissues of SGA plants. On the other hand, photosynthesis-related genes were highly down-regulated in crown tissues of SGA plants. In addition, transcript accumulation levels of shoot apical meristem (SGA)-related genes such as knotted-1 like homeobox (Knox) genes were also repressed in SGA plants. The microarray analysis strongly suggests that an autoimmune response-like reaction might be triggered by intergenomic incompatibility between the AB and U genomes in SGA. In addition, SAM-related and cell cycle-related genes were dramatically down-regulated in crown tissues of SGA, indicating that abnormalities of SAM are associated with the abnormal growth phenotypes in SGA.