Project description:Two varieties of Alfalfa plants (potato leaf hopper resistance line and sensitive line, provided by Forage Genetics International, West Salem, WI, USA) were selected to compare their transcriptomics in order to discover the mechanism of potato leaf hopper resistance in the resistant line.
Project description:Two alfalfa varieties, 'Chilean' (M. sativa ssp. sativa var. Chilean, drought sensitive) and 'Wisfal' (M. sativa ssp. falcata var. Wisfal, drought tolerant), with contrasting water use efficiency were subjected to water withholding for 11 days followed by re-watering. Samples were taken for well-watered plants and plants after five, eight, eleven days of drought stress as well as plants after recovery for one day following drought stress. Roots and shoots were sampled and analyzed separately by expression profiling using Affymetrix Medicago GeneChip.
Project description:Heat stress and extreme temperatures negatively affect plant development by disrupting regular cellular and biochemical functions, ultimately leading to reduced crop production. Recently, our group has shown through physiological experiments that miR156 overexpression resulted in an improved alfalfa response to heat stress. To further expand the scope of miR156 research, we employed a label-free quantification based quantitative proteomics approach to explore the effects of heat stress on protein levels in miR156OE alfalfa. Our major objective was to identify miR156-regulated gene products with differentially altered abundance under heat stress in alfalfa.
Project description:The gene expression profiles of wild-type and two nst1 mutants in Medicago truncatula were compared using 5-8th internodes in 50 days old plants.
Project description:Medicago truncatula Tnt-1 insertional mutant for MtTTG1 gene (NF977) versus the wild-type R108. The seed samples are harvested at 16 days after pollination. Their transcript profiles were compared.
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.
Project description:Alfalfa, [Medicago sativa (L.) sativa], a widely-grown perennial forage has potential for development as a cellulosic ethanol feedstock. The application of genomic approaches would advance development of alfalfa as a cellulosic feedstock. However, the genomics of alfalfa, a non-model species, is still in its infancy. The recent advent of RNA-Seq, a massively parallel sequencing method for transcriptome analysis, provides an opportunity to expand the identification of alfalfa genes and polymorphisms, and conduct in-depth transcript profiling. Cell walls in stems of alfalfa genotype 708 have higher cellulose and lower lignin concentrations compared to cell walls in stems of genotype 773. Using the Illumina GA-II platform, a total of 198,861,304 expression sequence tags (ESTs, 76 bp in length) were generated from cDNA libraries derived from elongating stem (ES) and post-elongation stem (PES) internodes of 708 and 773. These ESTs were de novo assembled into 132,153 unique sequences. By combining the de novo assembled ESTs (132,153 sequences) with our previously identified EST sequences (341,984 sequences, unpublished data), and the ESTs available from GenBank (12,371 sequences), we built the first Alfalfa Gene Index (MSGI 1.0). MSGI 1.0 contains 124,025 unique sequences including 22,729 tentative consensus sequences (TCs), 22,315 singletons and 78,981 pseudo-singletons. We identified a total of 1, 294 simple sequence repeats (SSR) among the sequences in MSGI 1.0. In addition, a total of 10,826 single nucleotide polymorphisms (SNPs) were predicted between the two genotypes. Transcript profiling of stem internodes of genotypes 708 and 773 was conducted by quantifying the number of Illumina EST reads that were mapped to sequences in MSGI 1.0. We identified numerous candidate genes that may play a role in stem development as well as candidate genes that may contribute to the differences in cell wall composition in stems of the two genotypes. Our results demonstrate that RNA-Seq can be successfully used for gene identification, polymorphism detection and transcript profiling in alfalfa, a non-model, allogamous, autotetraploid species. The alfalfa gene index (MSGI 1.0) assembled in this study, and the SNPs, SSRs and candidate genes identified can be used to improve alfalfa as a cellulosic feedstock. Examination of 2 different tissue types at different developmental stages (Elongating vs. post-elongation stem internodes) in two alfalfa genotypes (708 and 773) with divergent cell wall composition in stems.