Project description:Small RNAs (21-24 nt) are pivotal regulators of gene expression that guide both transcriptional and post-transcriptional silencing mechanisms in diverse eukaryotes, including most if not all plants. MicroRNAs (miRNAs) and short interfering RNAs (siRNAs) are the two major types, both of which have a demonstrated and important role in plant development, stress responses and pathogen resistance. In this work, we used a deep sequencing approach (Sequencing-By-Synthesis, or SBS) to develop sequence resources of small RNAs from Nicotiana tabacum tissues (including leaves, flowers and pods). The high depth of the resulting datasets enabled us to examine in detail critical small RNA features as size distribution, tissue-specific regulation and sequence conservation between different organs in this species. We also developed database resources and a dedicated website (http://smallrna.udel.edu/) with computational tools for allowing other users to identify new miRNAs or siRNAs involved in specific regulatory pathways, verify the degree of conservation of these sequences in other plant species and map small RNAs on genes or larger regions of the maize genome under study.
Project description:Small RNAs (21-24 nt) are pivotal regulators of gene expression that guide both transcriptional and post-transcriptional silencing mechanisms in diverse eukaryotes, including most if not all plants. MicroRNAs (miRNAs) and short interfering RNAs (siRNAs) are the two major types, both of which have a demonstrated and important role in plant development, stress responses and pathogen resistance. In this work, we used a deep sequencing approach (Sequencing-By-Synthesis, or SBS) to develop sequence resources of small RNAs from Nicotiana tabacum tissues (including leaves, flowers and pods). The high depth of the resulting datasets enabled us to examine in detail critical small RNA features as size distribution, tissue-specific regulation and sequence conservation between different organs in this species. We also developed database resources and a dedicated website (http://smallrna.udel.edu/) with computational tools for allowing other users to identify new miRNAs or siRNAs involved in specific regulatory pathways, verify the degree of conservation of these sequences in other plant species and map small RNAs on genes or larger regions of the maize genome under study. Small RNA libraries were derived from leaves, flowers and pods of Nicotiana tabacum. Total RNA was isolated using the TriReagent (Molecular Research Center) for leaves and flowers, and the Plant RNA Purification Reagent (Invitrogen) for pods, and submitted to Illumina (Hayward, CA, http://www.illumina.com) for small RNA library construction using approaches described in (Lu et al., 2007) with minor modifications. The small RNA libraries were sequenced with the Sequencing-By-Synthesis (SBS) technology by Illumina. PERL scripts were designed to remove the adapter sequences and determine the abundance of each distinct small RNA. We thank Barbara Baker for providing the plant material as well as Kan Nobuta and Gayathri Mahalingam for assistance with the computational methods.
Project description:Transgenic tobacco (Nicotiana tabacum) expressing Caenorhabditis elegans cell death genes, Ced4 and Ced3, show evidence suggesting such expressions protect the plants from infestation by the plant parasitic nematode Meloidogyne incognita. Although positive results have been correlated with the gene expressions (data in preparation for publication; a draft of the publication can be provided upon request), the mechanism by which the nematode protection is manifested is not clearly understood. One possibility is that the C. elegans cell death proteins produced by the transgenic plants are being ingested and incorporated into the nematode’s own cell death pathway, leading to their demise. Alternatively, it is also possible that expression of the C. elegans cell death genes promotes the endogenous resistance genes of the plant, leading to nematode resistance. We want to test the later hypothesis by conducting a reference design microarray experiment to establish the expression profile of Ced3, and Ced4 homozygous plants and Ced3xCed4 double heterozygous plants in comparison with wild-type tobacco plants. If the hypothesis is correct, we expect to detect increased expression of pathogenicity-related genes in the transgenic plants. Furthermore, characterization of the expression profiles in these transgenic plants will provide us directionality for our future research on the elucidation of this resistance mechanism. Keywords: Reference design
Project description:The number of known proteins associated with plant lipid droplets (LDs) is small compared to other organelles. Many questions of LD biosynthesis and degradation remain open, also due to lack of candidate LD proteins whose characterization could help to elucidate their function in those processes. We performed a proteomic screen on LDs isolated from Nicotiana tabacum pollen tubes. Proteins that were highly enriched in the LD fraction compared to the total or cytosolic fraction where verified for LD localization via transient expression in tobacco pollen tubes. We also compared the isoforms of typical LD proteins found in the pollen tubes on a qualitative level to the isoforms found in tobacco seeds.
Project description:Genetically engineering Nicotiana tabacum to express Isoprene Synthase (ISPS) leads to changes in expression of genes assoiated with many growth regulator signaling pathways and signaling networks involved in abiotic and biotic stress responses.