Project description: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.
Project description:Gene expression patterns in roots of Camelina sativa with enhanced salinity tolerance arising from growth in soil treated with plant growth promoting bacteria producing 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase) or from expression of the corresponding acdS gene in transgenic lines. Salinity stress negatively affects crop production. However in camelina, grown in soils treated with PGPB producing 1-aminocyclopropane-1-carboxylate deaminase (acdS ) or transgenic lines expressing acdS exhibited increased salinity tolerance. AcdS reducing the level of stress ethylene to below the point where it is inhibitory to growth. Gene expression patterns in roots responding to salt stress was affected by the expression of acdS under the control of CaMV 35S or root-specific (rolD) promoters in transgenic lines, or by growth in soils treated with endophytic PGPB producing acdS indicate that the number of the genes were differentially expressed were more assigned to genome III in transgenic plants however in PGPB treated plants the number of the genes were differentially expressed were almost equally assigned to all three genomes. Different promoter may induce different set or even different homeologues genes in camelina with probably the same function in response to salt stress. Though root is not a photosynthetic tissue reduction of the ethylene in root cells has positive effect on plant photosynthetic machinery. The expression of the genes involved in minor CHO metabolism was up-regulated mainly in roots of acdS contain plants during salt stress. Moderate reduction in ethylene production has positive effect on root growth during salt stress but reduction of the ethylene higher than a certain level has negative effect on root growth due to reduction of the expression of the genes involved in root cell elongation. AcdS gene modulating the level of ROS in cells in the level that induce ROS signaling but preventing cellular damage by make a balance on up and down-regulation of the genes involved in oxidation-reduction process in root cells under salinity stress. The acdS containing PGPB (8R6) were mostly effected the ethylene signaling and ABA biosynthesis and signaling in positive way but transgenic line depends to the promoter affecting Auxin, JA and BR signaling or biosynthesis.
Project description:Growth in soil inoculated with plant growth promoting bacteria (PGPB) producing 1-aminocyclopropane-1-carboxylate |(ACC) deaminase or expressing of the corresponding acdS in transgenic lines reduces the decline in shoot length, shoot weight and photosynthetic capacity triggered by salt stress in Camelina sativa. Reducing the levels of stress ethylene decreases the expression of salt stress-responsive genes, specifically genes involved in development, senescence, chlorosis and leaf abscission that are highly induced by salt to the levels that may have a less negative effect on growth and productivity. Moderate expression of acdS under the promoter of the rolD promoter or growing plants in soil treated with the PGPB Pseudomonas migulae 8R6, were more effective in eliminating the expression of the genes involved in ethylene production and/or signaling than expression under the more active Cauliflower Mosaic Virus 35S promoter.
Project description:Camelina is an annual oilseed plant that is gaining momentum as a biofuel winter cover crop. Understanding gene regulatory networks (GRNs) is essential to deciphering plant metabolic pathways, including lipid metabolism. Here, we take advantage of a growing collection of gene expression datasets to predict transcription factors (TFs) associated with the control of Camelina lipid metabolism. Also, we performed RNA-seq assays of Camelina's seed at 5, 8, and 11 days post-anthesis (DPA) to improve the transcriptomic resolution of the early stages of the Camelina seed development. We identified ~350 TFs highly co-expressed with lipid-related genes (LRGs). After prioritizing the top 22 TFs for further validation, we identified DNA-binding sites and predicted target genes for 16/22 TF using DNA affinity purification sequencing (DAP-seq). Enrichment analyses supported the co-expression prediction for most TF candidates, and the comparison to Arabidopsis revealed some common themes and aspects unique to Camelina. Altogether, the integration of co-expression data and DNA-binding assays permitted us to generate a high-confident and shortlist of Camelina TFs involved in controlling lipid metabolism during seed development.