Project description:We used isobaric tags for relative and absolute quantitation (iTRAQ) to perform a quantitative proteomic analysis of immature spikes harvested from tetraploid near-isogenic lines of wheat with normal spikelete (NSs), FRSs, and RSs and investigated the molecular mechanisms of lateral meristem differentiation and development. This work provides valuable insight into the underlying functions of the lateral meristem and how it can produce differences in the branching of tetraploid wheat spikes.
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:Develpment of a diversity panel for tetraploid wheat which include wild emmer wheat from across its distribution ranges, domesticated emmer wheat, durum landraces and durum varieties.
Project description:Wheat is a cereal grain and one of the world’s major food crops. Recent advances in wheat genome sequencing are by now facilitating genomic and proteomic analyses of this crop. However, little is known about the protein levels of hexaploid versus tetraploid wheat cultivars, and knowledge on phosphorylated proteins still limited. Using our recently established (phospho)proteomic workflow, we performed a parallel analysis of the proteome and phosphoproteome on seedling leaves from two hexaploid wheat cultivars (Pavon 76 and USU-Apogee) and a tetraploid wheat (Senatore Cappelli). This revealed that a large portion of proteins and phosphosites can be quantified in all cultivars. Our shotgun proteomics data revealed a high similarity between hexaploid and tetraploid varieties with respect to protein abundance. However, we could identify a set of proteins that were differentially abundant between hexaploid and tetraploid cultivars. In addition, already at seedling stage, a small set of proteins were differential between the small (USU-Apogee) and larger hexaploid wheat cultivar (Pavon 76), which could potentially act as growth predictors. Finally, the phosphosites identified in this study can be retrieved from the in-house developed plant PTM-Viewer (bioinformatics.psb.ugent.be/webtools/ptm_viewer/), making this the first repository for phosphorylated wheat proteins. This paves the way for further in depth, quantitative (phospho)proteome-wide differential analyses upon a specific trigger or environmental change.
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: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: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:Hybrid chlorosis, one of the hybrid incompatibilities, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In our previous study, hybrid chlorosis was observed in the wheat triploids between a tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlying hybrid chlorosis are not well understood. Here, we performed cytological and comparative gene expression analyses in leaves to characterize the abnormal growth in wheat synthetics showing mild and severe chlorosis symptom. In addition, disease resistance was comparatively assessed. A number of carbohydrate metabolism- and defense-related genes were markedly up-regulated in the hybrid chlorosis lines, and abnormal chloroplasts were formed in the mesophyll cells before the leaves turned to be yellowish. The mild chlorosis plants showed increased resistance to a wheat blast fungus, although little significant differences of agricultural traits were found between the wild-type and mild chlorosis-showing plants. These observations suggest that the senescence processes might be accelerated in the hybrid chlorosis lines of wheat synthetics. Moreover, the negative effects on biomass can be minimized and the substantial fitness may be obtained under pathogen-polluted conditions in the mild chlorosis-showing wheat synthetics.