ABSTRACT: Nicotiana tabacum degradome analysis using high definition adapters proves an efficient targeting method against the Tomato leaf curl New Delhi virus using artificial ta-siRNAs [sRNA-seq]
Project description:RNA interference (RNAi) is a conserved, RNA-mediated, regulatory mechanism in eukaryotes. In plants, it plays an important role in growth, development and resistance against viral infections. As a counter-defence, plant viruses, e.g. geminiviruses, encode RNAi suppressors, such as AC2, AC4 and AV2. To obtain Nicotiana tabacum virus resistant plants against Tomato leaf curl New Delhi virus (ToLCNDV), we employ the biogenesis pathway of a class of endogenous siRNAs, the trans-acting siRNAs (ta-siRNAs), by engineering artificial ta-siRNAs (ata-siRNAs) targeting the AC2 (TRiV-AC2) and AC4 (TRiV-AC4) RNAi suppressors using miRNA390 dual target sites. The mode of action of ta-siRNAs comprises of the cleavage of the target (similar to the miRNA targeting). Using degradome approaches, the abundance of the resulting 3' fragment of the cleaved transcript can be quantified and the precise localization of the cleavage on the target mRNA can be identified. We sequenced degradome libraries of Nicotiana tabacum plants infected with ToLCNDV which were treated with the ata-siRNA-AC2 construct; mock-treated plants were used as controls. Following quality checks, the abundance distributions of the degradation fragments were normalized. The transcripts with different cleavage patterns was the AC2, supporting the conclusion that an efficient cleavage of the target occurred, without significant off-target effects.
Project description:RNA interference (RNAi) is a conserved, RNA-mediated, regulatory mechanism in eukaryotes. In plants, it plays an important role in growth, development and resistance against viral infections. As a counter-defence, plant viruses, e.g. geminiviruses, encode RNAi suppressors, such as AC2, AC4 and AV2. To obtain Nicotiana tabacum virus resistant plants against Tomato leaf curl New Delhi virus (ToLCNDV), we employ the biogenesis pathway of a class of endogenous siRNAs, the trans-acting siRNAs (ta-siRNAs), by engineering artificial ta-siRNAs (ata-siRNAs) targeting the AC2 (TRiV-AC2) and AC4 (TRiV-AC4) RNAi suppressors using miRNA390 dual target sites. The mode of action of ta-siRNAs comprises of the cleavage of the target (similar to the miRNA targeting). Using degradome approaches, the abundance of the resulting 3' fragment of the cleaved transcript can be quantified and the precise localization of the cleavage on the target mRNA can be identified. We sequenced degradome libraries of Nicotiana tabacum plants infected with ToLCNDV which were treated with the ata-siRNA-AC2 construct; mock-treated plants were used as controls. Following quality checks, the abundance distributions of the degradation fragments were normalized. The transcripts with different cleavage patterns was the AC2, supporting the conclusion that an efficient cleavage of the target occurred, without significant off-target effects.
Project description:Nicotiana tabacum degradome analysis using high definition adapters proves an efficient targeting method against the Tomato leaf curl New Delhi virus using artificial ta-siRNAs [PARE]
Project description:Nicotiana tabacum degradome analysis using high definition adapters proves an efficient targeting method against the Tomato leaf curl New Delhi virus using artificial ta-siRNAs
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:Small RNAs, including ta-siRNAs, play crucial roles in various processes in plants. Efforts have been made for decades to elucidate the biogenesis and function of ta-siRNAs. Though the key proteins involved in ta-siRNA biogenesis have been identified, the subcellular localization where ta-siRNAs are processed remains largely unexplored. Remarkably, non-coding TAS transcripts were reported to be bound by ribosomes, the machinery responsible for protein translation. Utilizing edited TAS genes in Arabidopsis, a combination of sRNA-seq, mRNA-seq, RIP-seq, and degradome-seq was employed to investigate the role of ribosomes in ta-siRNA biogenesis in this study. In the two-hit model, deletion of ribosome-binding regions resulted in a decrease in the abundance of intact TAS3 transcripts but did not significantly affect ta-siRNAs production or the efficiency of miRNA-guided cleavage. Conversely, the deletion of ribosome-binding regions led to a significant reduction in ta-siRNA abundance without affecting mRNA levels in the one-hit model. These findings indicate that in the two-hit model, ribosomes primarily stabilize TAS transcripts, while in the one-hit model, they suppress miRNA cleavage but facilitate subsequent processing. Collectively, this study proposes a model that ribosomes play distinct roles in the one-hit and two-hit models of ta-siRNA biogenesis, and provides a new angle to investigate the tangled connection between small RNAs, including miRNA and ta-siRNA, and translation.
Project description:Small RNAs, including ta-siRNAs, play crucial roles in various processes in plants. Efforts have been made for decades to elucidate the biogenesis and function of ta-siRNAs. Though the key proteins involved in ta-siRNA biogenesis have been identified, the subcellular localization where ta-siRNAs are processed remains largely unexplored. Remarkably, non-coding TAS transcripts were reported to be bound by ribosomes, the machinery responsible for protein translation. Utilizing edited TAS genes in Arabidopsis, a combination of sRNA-seq, mRNA-seq, RIP-seq, and degradome-seq was employed to investigate the role of ribosomes in ta-siRNA biogenesis in this study. In the two-hit model, deletion of ribosome-binding regions resulted in a decrease in the abundance of intact TAS3 transcripts but did not significantly affect ta-siRNAs production or the efficiency of miRNA-guided cleavage. Conversely, the deletion of ribosome-binding regions led to a significant reduction in ta-siRNA abundance without affecting mRNA levels in the one-hit model. These findings indicate that in the two-hit model, ribosomes primarily stabilize TAS transcripts, while in the one-hit model, they suppress miRNA cleavage but facilitate subsequent processing. Collectively, this study proposes a model that ribosomes play distinct roles in the one-hit and two-hit models of ta-siRNA biogenesis, and provides a new angle to investigate the tangled connection between small RNAs, including miRNA and ta-siRNA, and translation.
Project description:Small RNAs, including ta-siRNAs, play crucial roles in various processes in plants. Efforts have been made for decades to elucidate the biogenesis and function of ta-siRNAs. Though the key proteins involved in ta-siRNA biogenesis have been identified, the subcellular localization where ta-siRNAs are processed remains largely unexplored. Remarkably, non-coding TAS transcripts were reported to be bound by ribosomes, the machinery responsible for protein translation. Utilizing edited TAS genes in Arabidopsis, a combination of sRNA-seq, mRNA-seq, RIP-seq, and degradome-seq was employed to investigate the role of ribosomes in ta-siRNA biogenesis in this study. In the two-hit model, deletion of ribosome-binding regions resulted in a decrease in the abundance of intact TAS3 transcripts but did not significantly affect ta-siRNAs production or the efficiency of miRNA-guided cleavage. Conversely, the deletion of ribosome-binding regions led to a significant reduction in ta-siRNA abundance without affecting mRNA levels in the one-hit model. These findings indicate that in the two-hit model, ribosomes primarily stabilize TAS transcripts, while in the one-hit model, they suppress miRNA cleavage but facilitate subsequent processing. Collectively, this study proposes a model that ribosomes play distinct roles in the one-hit and two-hit models of ta-siRNA biogenesis, and provides a new angle to investigate the tangled connection between small RNAs, including miRNA and ta-siRNA, and translation.
Project description:Small RNAs, including ta-siRNAs, play crucial roles in various processes in plants. Efforts have been made for decades to elucidate the biogenesis and function of ta-siRNAs. Though the key proteins involved in ta-siRNA biogenesis have been identified, the subcellular localization where ta-siRNAs are processed remains largely unexplored. Remarkably, non-coding TAS transcripts were reported to be bound by ribosomes, the machinery responsible for protein translation. Utilizing edited TAS genes in Arabidopsis, a combination of sRNA-seq, mRNA-seq, RIP-seq, and degradome-seq was employed to investigate the role of ribosomes in ta-siRNA biogenesis in this study. In the two-hit model, deletion of ribosome-binding regions resulted in a decrease in the abundance of intact TAS3 transcripts but did not significantly affect ta-siRNAs production or the efficiency of miRNA-guided cleavage. Conversely, the deletion of ribosome-binding regions led to a significant reduction in ta-siRNA abundance without affecting mRNA levels in the one-hit model. These findings indicate that in the two-hit model, ribosomes primarily stabilize TAS transcripts, while in the one-hit model, they suppress miRNA cleavage but facilitate subsequent processing. Collectively, this study proposes a model that ribosomes play distinct roles in the one-hit and two-hit models of ta-siRNA biogenesis, and provides a new angle to investigate the tangled connection between small RNAs, including miRNA and ta-siRNA, and translation.