Project description:Abstract: In order to understand the expression patterns of miRNAs in alfalfa under alkali stress, small RNA sequencing was performed on alfalfa roots at different time points under alkali stress, and miRNAs were identified and analyzed.
Project description:Abstract: In order to clarify the response mechanism of alfalfa under alkali stress, the transcriptome of roots was sequenced at different time points after stress and the expression patterns of all genes were analyzed.
Project description:Alkaline salts (e.g., NaHCO3 and Na2CO3) causes more severe morphological and physiological damage to plants than neutral salts (e.g., NaCl and Na2SO4) due to differences in pH. The mechanism by which plants respond to alkali stress is not fully understood, especially in plants having symbotic relationships such as alfalfa (Medicago sativa L.). Therefore, a study was designed to evaluate the metabolic response of the root-nodule symbiosis in alfalfa under alkali stress using comparative metabolomics. Rhizobium-nodulized (RI group) and non-nodulized (NI group) alfalfa roots were treated with 200 mmol/L NaHCO3 and, roots samples were analyzed for malondialdehydyde (MDA), proline, glutathione (GSH), superoxide dismutase (SOD), and peroxidase (POD) content. Additionally, metabolite profiling was conducted using gas chromatography combined with time-of-flight mass spectrometry (GC/TOF-MS). Phenotypically, the RI alfalfa exhibited a greater resistance to alkali stress than the NI plants examined. Physiological analysis and metabolic profiling revealed that RI plants accumulated more antioxidants (SOD, POD, GSH), osmolytes (sugar, glycols, proline), organic acids (succinic acid, fumaric acid, and alpha-ketoglutaric acid), and metabolites that are involved in nitrogen fixation. Our pairwise metabolomics comparisons revealed that RI alfalfa plants exhibited a distinct metabolic profile associated with alkali putative tolerance relative to NI alfalfa plants. Data provide new information about the relationship between non-nodulized, rhizobium-nodulized alfalfa and alkali resistance.
Project description:Plant roots are the primary site of perception and injury for saline-alkaline stress. The current knowledge of the saline-alkaline stress transcriptome is most focused on salt (NaCl) stress. Only a little alkaline (NaHCO3) stress transcriptome is limited to one time point after stress. Time-course analysis and comparative investigation on roots in the alkaline stress condition are needed to understand the gene response networks that are subject to alkaline tolerance. We used microarrays to detail the global programme of gene expression underlying NaHCO3 treatment and identified distinct classes of regulated genes during this process.
Project description:To explore the mechanisms of cotton response to this alkaline stress, we used next-generation sequencing (NGS) technology to study transcriptional changes of cotton under NaHCO3 alkaline stress. A total of 18,230 and 11,177 differentially expressed genes (DEGs) were identified in cotton roots and leaves, respectively. Gene ontology (GO) analysis indicated the enrichment of DEGs involved in various stimuli or stress responses. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEGs associated with plant hormone signal transduction, amino acid biosynthesis, and biosynthesis of secondary metabolites were regulated in response to the NaHCO3 stress. We further analyzed genes enriched in secondary metabolic pathways and found that secondary metabolites were regulated to eliminate the reactive oxygen species (ROS) and improve the cotton tolerance to the NaHCO3 stress. In this study, we learned that the toxic effect of NaHCO3 was more profound than that of NaOH at the same pH. Thus, Na+, HCO3- and pH had a great impact on the growth of cotton plant. The novel biological pathways and candidate genes for the cotton tolerance to NaHCO3 stress identified from the study would be useful in the genetic improvement of the alkaline tolerance in cotton.
Project description:Plant roots are the primary site of perception and injury for saline-alkaline stress. The current knowledge of the saline-alkaline stress transcriptome is most focused on salt (NaCl) stress. Only a little alkaline (NaHCO3) stress transcriptome is limited to one time point after stress. Time-course analysis and comparative investigation on roots in the alkaline stress condition are needed to understand the gene response networks that are subject to alkaline tolerance. We used microarrays to detail the global programme of gene expression underlying NaHCO3 treatment and identified distinct classes of regulated genes during this process. Three week old Glycine soja seedling roots from 3cm root apex were harvested in two independent biological replicates after 0, 0.5, 1, 3, 6, 12 and 24h treatment with 50mmol/L NaHCO3 stress for RNA extraction and hybridization on Affymetrix microarrays. To minimize biological variance, roots from three plants originating from the same experiment, condition and cultivar was pooled.
Project description:Soil alkalinity greatly affects plant growth and crop productivity. Although RNA-Seq analyses have been conducted to investigate genome-wide gene expression in response to alkaline stress in many plants, the expression of alkali-responsive genes in rice has not previously investigated. In this study, the transcriptomic data were compared between an alkaline-tolerant [WD20342 (WD)] and an alkaline-sensitive [Caidao (CD)] rice cultivar under control and alkaline stress conditions. A total of 962 important alkali-responsive (IAR) genes from highly differentially expressed genes (DEGs) were identified, including 28 alkaline-resistant cultivar-related genes, 771 alkaline-sensitive cultivar-related genes and 163 cultivar-non-specific genes. Gene ontology (GO) analysis suggested the enrichment of IAR genes involved in response to various stimuli or stresses. According to KEGG pathway analysis, the IAR genes were related primarily to plant hormone signal transduction and biosynthesis of secondary metabolites. Additionally, among these 962 IAR genes, 74 were transcription factors and 15 occurred with differential alternative splicing between the different samples after alkaline treatment. Our results provide a valuable resource on alkali-responsive genes and should benefit the improvement of alkaline stress tolerance in rice.
2018-07-12 | GSE104928 | GEO
Project description:Transcriptome for alfalfa roots under alkaline stress
Project description:Alfalfa is the most produced perennial forage crop in Canada. Drought stress is a major form of abiotic stress, affecting its productivity and annual yield. A small RNA, miR156, plays a major role in drought tolerance by downregulating downstream SPL genes, but its effects at the proteome level are unknown. In this study, the protein level perturbations of miR156 overexpression (A8) and empty vector (EV) control genotypes were compared under drought stress. Using label-free quantification, 3,000 protein groups were identified, of which 68 were upregulated in A8 and 84 were downregulated relative to EV under control conditions. Conversely, under drought stress, 610 proteins were upregulated and only 52 proteins were downregulated in A8 relative to EV. Functional analysis using PlantRegMap showed that the enriched proteins are likely involved in biological and molecular processes including antioxidant response, response to stress, signal transduction and biosynthesis of secondary metabolites. These proteins/pathways might be involved in the enhancement of drought stress tolerance mediated by miR156. Protein groups related to signaling, such as MAP kinase, calcium-dependent protein kinase, protein phosphatase 2C, and transcriptional regulators including bZIP and zinc finger proteins were found to be differentially expressed when a search was conducted against a drought stress gene database. The proteomic dataset was validated by immunoblotting of selected proteins. The results of this study provide a better understanding and insight into the role of miR156 in drought stress tolerance in alfalfa at the proteomic level.