Gene Expression NebulasSummary: Soil salinity presents a notable challenge to agriculture and to increasing the use marginal lands for farming. Here we provide a detailed analysis of the physiology, chemistry and gene expression patterns in roots and shoots of Camelina sativa in response to salt stress. Salt treatment reduced shoot, but not root length. Root and shoot weight were affected by salt, as was photosynthetic capacity. Salt treatment did not alter micro-element concentration in shoots, but increased macro-element (Ca and Mg) levels. Gene expression patterns in shoots indicated that salt stress may have led to shuttling of Na+ from the cytoplasm to the tonoplast and to an increase in K+ and Ca+2 import into the cytoplasm. In roots, gene expression patterns indicated that Na+ was exported from the cytoplasm by the SOS pathway and that K+ was imported in response to salt. Genes encoding proteins involved in chelation and storage were highly up-regulated in shoots, while metal detoxification appeared to involve various export mechanisms in roots. In shoots, genes involved in secondary metabolism leading to lignin, anthocyanin and wax production were up-regulated, probably to improve desiccation tolerance. Partial genome expression partitioning was observed in roots and shoots based on the expression of homeologous genes from the three C. sativa genomes. Genome I and II were involved in the response to salinity stress to about the same degree, while about 10 % more differentially-expressed genes were associated with Genome III. This study has provided valuable information and insight into the response of camelina to salt stress. Examination of this data and comparison to similar studies in more halophytic species will allow development of even more salt-tolerant varieties of this emerging industrial crop.
Overall Design: Camelina roots and shoots, with or without salt treatment, were analyzed. 3 replicates of each (root after salt treatment, root without salt treatment, shoot after salt treatment, shoot without salt treatment) were compared.
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| Growth Protocol: | Camelina sativa cv. DH55 seeds were sown in soil-less potting mixture (Stringham, 1971) in 10 x 10 x 8 cm square pots. Plants were grown in a controlled growth chamber (16 h light/8 h dark, 20/17°C) supplemented with halogen lights |
| Treatment Protocol: | NaCl solutions at 192 mM were prepared to obtain a solution with an electrical conductivitie (EC) of 15 dSm-1 at 20°C. 50 ml of tap water (EC 1,248 µSm-1) was applied daily to each pot and replaced with 50 ml of saline solution (EC 15 dSm-1) 7 days after sowing. The accumulation of salt in the pots was controlled by draining and the EC of the drained water was measured weekly. Shoot and root matter was harvested 21 days after the initial salt treatment just before the plants began to bolt. |
| Extract Protocol: | Total RNA was extracted using the RNeasy Plant Mini Kit (Qiagen Inc.) |
| Library Construction Protocol: | cDNA libraries were prepared using the TruSeq Stranded mRNA and Total RNA Library Prep kits with TruSeq LT indexed adaptors (Illumina Inc.). |
| Molecule Type: | polyA(+) RNA |
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| Library Layout: | PAIRED |
| 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 | Condition 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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