Project description:In this study, we explored the metabolome and transcriptome of the ripe fruit in nine landrace accessions representing the seven genetic groups and compared them to the mature fruit of the wild progenitor S. pimpinellifolium. The goal is to shed light in understanding the factors responsible for acquiring tomato fruit quality (taste and flavour) at molecular level during the domestication process.
Project description:Gossypium barbadense is widely cultivated because of its extra-long staple cotton with superior luster, silkiness and high yield. These economically important traits were selected during initial domestication of an agronomically inferior wild ancestor, followed by millennia of human- mediated selection. To reveal the effects of this history on the cotton fiber transcriptome, we conducted comparative expression profiling on mechanically isolated fiber cells at three different stages encompassing early, mid, and late fiber elongation in wild (K101) and domesticated (Pima S-7) accessions, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes across developmental stages was different in the two accessions, with a shift toward greater change earlier in cultivated than in wild G. barbadense. Approximately 4200 genes were differentially expressed between wild and domesticated accessions at one or more of the stages studied. Domestication appears to have led to enhanced modulation of cellular redox levels and the avoidance or delay of stress-like processes. Prolonged fiber growth in cultivated relative to wild G. barbadense is associated with upregulation of signal transduction and hormone signaling genes and down-regulation of cell wall maturation genes. Clues are provided into the processes and genes that may unwittingly have been selected by humans during domestication and development of modern elite lines. Several of the transcriptomic differences between wild and domesticated G. barbadense described here appear to have parallels in a second domesticated cotton species, Gossypium hirsutum, suggesting that replicated domestication of two different species has resulted in overlapping, parallel, metabolic transformations.
Project description:Common wheat is an allohexaploid species, derived through endoreduplication of an inter-specific triploid hybrid produced from a cross between cultivated tetraploid wheat and the wild diploid relative Aegilops tauschii Coss. Hybrid incompatibilities, including hybrid necrosis, have been observed in triploid wheat hybrids. A limited number of Ae. tauschii accessions show hybrid lethality in triploid hybrids crossed with tetraploid wheat due to developmental arrest at the early seedling stage, which is termed severe growth abortion (SGA). Despite the potential severity of this condition, the genetic mechanisms underlying SGA are not well understood. We conducted comparative analyses of gene expression profiles in crown tissues to characterize developmental arrest in triploid hybrids displaying SGA. A number of defense-related genes were highly up-regulated, whereas many transcription factor genes, such as the KNOTTED1-type homeobox gene, which function in shoot apical meristem (SAM) and leaf primordia, were down-regulated in the crown tissues of SGA plants. Transcript accumulation levels of cell cycle-related genes were also markedly reduced in SGA plants, and no histone H4-expressing cells were observed in the SAM of SGA hybrid plants. Our findings demonstrate that SGA shows unique features among other types of abnormal growth phenotypes, such as type II and III necrosis.
Project description:Gossypium barbadense is widely cultivated because of its extra-long staple cotton with superior luster, silkiness and high yield. These economically important traits were selected during initial domestication of an agronomically inferior wild ancestor, followed by millennia of human- mediated selection. To reveal the effects of this history on the cotton fiber transcriptome, we conducted comparative expression profiling on mechanically isolated fiber cells at three different stages encompassing early, mid, and late fiber elongation in wild (K101) and domesticated (Pima S-7) accessions, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes across developmental stages was different in the two accessions, with a shift toward greater change earlier in cultivated than in wild G. barbadense. Approximately 4200 genes were differentially expressed between wild and domesticated accessions at one or more of the stages studied. Domestication appears to have led to enhanced modulation of cellular redox levels and the avoidance or delay of stress-like processes. Prolonged fiber growth in cultivated relative to wild G. barbadense is associated with upregulation of signal transduction and hormone signaling genes and down-regulation of cell wall maturation genes. Clues are provided into the processes and genes that may unwittingly have been selected by humans during domestication and development of modern elite lines. Several of the transcriptomic differences between wild and domesticated G. barbadense described here appear to have parallels in a second domesticated cotton species, Gossypium hirsutum, suggesting that replicated domestication of two different species has resulted in overlapping, parallel, metabolic transformations. Two accessions of G. barbadense were studied, the elite cultivar, Pima S-7, and a wild accession from Bolivia, K101. Seeds of both accessions were sown in sterilized potting mix in the Pohl Conservatory at Iowa State University, Ames, IA, and three biological replicates were grown for 3-5 months. Flowers were tagged at anthesis and harvested at three time points, 2, 10, and 20 days postanthesis. For each of three biological replicates, ovules were excised, frozen in liquid nitrogen, and stored at -80C.
Project description:The three subgenomes (B, A and D) of common wheat (2n=6x=42) are largely intact, which makes extraction of the BBAA subgenomes as organismally independent genomes possible. Availability of such novel extracted tetraploid wheat (Extracted-tetra) provides a unique opportunity to study whether and to what extent the BBAA subgenomes of common wheat have been irreversibly modified, as well as its attendant biological consequences, during their evolutionary trajectory as allohexaploidy. We report here that the extracted-tetra is stable in karyotype but with severely deteriorated phenotypes. Microarray-based transcriptome analysis revealed a substantial portion of differentially expressed genes (down- or up-regulation) between extracted and natural tetraploid wheat, Triticum turgidum, which exceeded the transcriptome divergence at tetraploid level, implying reinforced effects of allopolyploidization and domestication at the allohexaploid level. Great majority of the differentially expressed genes showed additive expression in a resynthesized allohexaploid wheat (parented by Extracted-tetra), indicating transcriptome modifications to the BBAA subgenomes are largely irreversible. Analysis of a newly synthesized allohexaploid wheat (parented by T. turgidum) suggests that whereas most of the modified genes are accrued evolutionary changes, some showed immediate regulation post-allohexaploidization and evolutionary perseverance. Homeologue-specific pyrosequencing of 44 genes revealed either concordant or independent expression changes to the B and A homeologues. The Extracted-tetra vs.T. turgidum down-regulated genes showed enrichment for distinct GO categories.
Project description:The lack of MIRNA set and genome sequence of O. rufipogon (the ancestor of the cultivated rice) has limited to answer the role of MIRNA genes in rice domestication. In this study, a genome, three small RNA populations and a degradome of O.rufipogon were sequenced by Illumina platform and miRNA expression were investigated by miRNA chips. A de novo genome was assembled using ~55x coverage of raw sequencing data and a total of 387 MIRNAs were identified in the O. rufipogon genome based on ~5.2 million unique small RNA reads from three different tissues of O. rufipogon. Of these O. rufipogon MIRNAs, 259 were not found in the cultivated rice, suggesting loss of these MIRNAs in the cultivated rice. We also found that 48 MIRNAs were novel in the cultivated rice, suggesting that they were potential targets of domestication selection. Some miRNAs showed significant expression difference in the wild and cultivated rice, suggesting that expression of miRNA could also be a target of domestication, as demonstrated for the miR164 family. Our results illustrated MIRNA genes, like protein-coding genes, were significantly shaped during rice domestication and could be one of the driven forces contributed to rice domestication.
Project description:The three subgenomes (B, A and D) of common wheat (2n=6x=42) are largely intact, which makes extraction of the BBAA subgenomes as organismally independent genomes possible. Availability of such novel extracted tetraploid wheat (Extracted-tetra) provides a unique opportunity to study whether and to what extent the BBAA subgenomes of common wheat have been irreversibly modified, as well as its attendant biological consequences, during their evolutionary trajectory as allohexaploidy. We report here that the extracted-tetra is stable in karyotype but with severely deteriorated phenotypes. Microarray-based transcriptome analysis revealed a substantial portion of differentially expressed genes (down- or up-regulation) between extracted and natural tetraploid wheat, Triticum turgidum, which exceeded the transcriptome divergence at tetraploid level, implying reinforced effects of allopolyploidization and domestication at the allohexaploid level. Great majority of the differentially expressed genes showed additive expression in a resynthesized allohexaploid wheat (parented by Extracted-tetra), indicating transcriptome modifications to the BBAA subgenomes are largely irreversible. Analysis of a newly synthesized allohexaploid wheat (parented by T. turgidum) suggests that whereas most of the modified genes are accrued evolutionary changes, some showed immediate regulation post-allohexaploidization and evolutionary perseverance. Homeologue-specific pyrosequencing of 44 genes revealed either concordant or independent expression changes to the B and A homeologues. The Extracted-tetra vs.T. turgidum down-regulated genes showed enrichment for distinct GO categories. Structurally, the three constituent subgenomes of common wheat, BB, AA and DD, are largely intact with only a few inter-subgenomic translocations. Because of these unique attributes, it is feasible to extract the BBAA subgenomes from the common wheat BBAADD genome by hybridization to a durum line and repeated back-crossing to the hexaploid parent, restituting a novel type of extracted tetraploid wheat, namely Extracted-tetr, with a genome constitution BBAA, virtually identical to the subgenomes BBAA of its common wheat donor. Availability of the extracted-tetra, the resynthesized allohexaploid wheat parented by the extracted-tetra, and newly synthesized allohexaploid wheat parented by natural tetraploid wheat, T. turgidum, provides an excellent system to address the issues of whether and to what extent transcriptome modifications to the BBAA subgenomes of common wheat have occurred since its formation ca. 10,000 years ago, timing of the modifications, and their biological consequences. Here, we have addressed these issues by microarray-based transcriptome analysis.
Project description:A major effort is underway to study the natural variation within the model plant species, Arabidopsis thaliana. Much of this effort is focused on genome resequencing, however the translation of genotype to phenotype will be largely effected through variations within the transcriptomes at the sequence and expression levels. To examine the cross-talk between natural variation in genomes and transcriptomes, we have examined the transcriptomes of three divergent A. thaliana accessions using tiling arrays. Combined with genome resequencing efforts, we were able to adjust the tiling array datasets to account for polymorphisms between the accessions and therefore gain a more accurate comparison of the transcriptomes. The corrected results for the transcriptomes allowed us to correlate higher gene polymorphism with greater variation in transcript level among the accessions. Our results demonstrate the utility of combining genomic data with tiling arrays to assay non-reference accession transcriptomes. Wild type accessions Col-0, Bur-0 and C24 were grown on soil at 23M-BM-0C with a 16 hour light period. Inflorescence tissue up to floral stage 14 was used for RNA extraction. Samples were collected 7-8 hours into the light period, with tissue from five plants pooled for each sample. RNA samples were converted into double stranded and hybridized to whole genome tiling arrays (Affymetrix Arabidopis Tiling1.0RM-BM-.). Three biological replicates were performed for each accession.
Project description:A major effort is underway to study the natural variation within the model plant species, Arabidopsis thaliana. Much of this effort is focused on genome resequencing, however the translation of genotype to phenotype will be largely effected through variations within the transcriptomes at the sequence and expression levels. To examine the cross-talk between natural variation in genomes and transcriptomes, we have examined the transcriptomes of three divergent A. thaliana accessions using tiling arrays. Combined with genome resequencing efforts, we were able to adjust the tiling array datasets to account for polymorphisms between the accessions and therefore gain a more accurate comparison of the transcriptomes. The corrected results for the transcriptomes allowed us to correlate higher gene polymorphism with greater variation in transcript level among the accessions. Our results demonstrate the utility of combining genomic data with tiling arrays to assay non-reference accession transcriptomes. Wild type accessions Col-0 were grown on soil at 16M-BM-0C with a 16 hour light period. Inflorescence tissue up to floral stage 14 was used for RNA extraction. Samples were collected 7-8 hours into the light period, with tissue from five plants pooled for each sample. RNA samples were converted into double stranded and hybridized to whole genome tiling arrays (Affymetrix Arabidopis Tiling1.0RM-BM-.). Three biological replicates were performed for each accession.