Gene Expression
Nebulas
Gene Expression NebulasSummary: The Reduced Height (Rht) genes formed the basis for the green revolution in wheat by decreasing plant height and increasing productive tillers. There are two current widely used Rht mutant alleles, Rht-B1b and Rht-D1b. Both reduce plant height by 20% and increase seed yield by 5-10%. They are also associated with decreased seed size and protein content. Here we tested the degree to which Rht-B1b impacts flag leaf photosynthetic rates and carbon and nitrogen partitioning to the flag leaf and grain during grain fill under field conditions using near isogenic lines (NILs) that were either standard height (Rht-B1a) or semi-dwarf (Rht-B1b). The results demonstrate that at anthesis, Rht-B1b reduces flag leaf photosynthetic rate per unit area by 18% and chlorophyll A content by 23%. Rht-B1b significantly reduced grain protein beginning at 14 days post anthesis with the greatest difference seen at 21 days post anthesis (DPA) (12%). Rht-B1b also significantly decreased individual seed weight beginning at 21 DPA and by 15.2% at 28 DPA. Global expression analysis using RNA extracted from developing leaves and stems demonstrated that genes associated with carbon and nitrogen metabolism are not substantially altered by Rht-B1b. From this study, we conclude that Rht-B1b reduces flag leaf photosynthetic rate at flowering while changes in grain composition begin shortly after anthesis.
Overall Design: Total RNA was collected from leaf and stem tissue from plants at 14 days past anthesis. Three samples were taken from plants carrying the semi-dwarfing allele Rht-B1b and three samples were taken from plants without the semi-dwarfing allele.
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| Growth Protocol: | Plants were grown under field conditions near Bozeman, MT (latitude 45.6N, longitude 111.00W). Plants were irrigated with 5cm of water on week pre- and post-anthesis. |
| Treatment Protocol: | Plants either carried the mutant semi-dwarfing allele, Rht-B1b, or the wildtype tall allele, Rht-B1a. |
| Extract Protocol: | Total RNA was extracted in accordance with the QIAGEN RNeasy Plant Mini kit and quantified using an Agilent Bioanalyzer. |
| Library Construction Protocol: | Libraries were prepared according to Illumina's TruSeq Stranded mRNA Library prep. |
| Molecule Type: | poly(A)+ RNA |
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| Library Layout: | SINGLE |
| Library Strand: | Forward |
| Platform: | ILLUMINA |
| Instrument Model: | Illumina HiSeq 2500 |
| Strand-Specific: | Specific |
| Data Resource | GEN Sample ID | GEN Dataset ID | Project ID | BioProject ID | Sample ID | Sample Name | BioSample ID | Sample Accession | Experiment Accession | Release Date | Submission Date | Update Date | Species | Race | Ethnicity | Age | Age Unit | Gender | Source Name | Tissue | Cell Type | Cell Subtype | Cell Line | Disease | Disease State | Development Stage | Mutation | Phenotype | Case Detail | Control Detail | Growth Protocol | Treatment Protocol | Extract Protocol | Library Construction Protocol | Molecule Type | Library Layout | Strand-Specific | Library Strand | Spike-In | Strategy | Platform | Instrument Model | Cell Number | Reads Number | Gbases | AvgSpotLen1 | AvgSpotLen2 | Uniq Mapping Rate | Multiple Mapping Rate | Coverage Rate |
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