Identification of wounding and topping responsive small RNAs in tobacco (Nicotiana tabacum)

Abstract

BackgroundMicroRNAs (miRNAs) and short interfering RNAs (siRNAs) are two major classes of small RNAs. They play important regulatory roles in plants and animals by regulating transcription, stability and/or translation of target genes in a sequence-complementary dependent manner. Over 4,000 miRNAs and several classes of siRNAs have been identified in plants, but in tobacco only computational prediction has been performed and no tobacco-specific miRNA has been experimentally identified. Wounding is believed to induce defensive response in tobacco, but the mechanism responsible for this response is yet to be uncovered.ResultsTo get insight into the role of small RNAs in damage-induced responses, we sequenced and analysed small RNA populations in roots and leaves from wounding or topping treated tobacco plants. In addition to confirmation of expression of 27 known miRNA families, we identified 59 novel tobacco-specific miRNA members of 38 families and a large number of loci generating phased 21- or 24-nt small RNAs (including ta-siRNAs). A number of miRNAs and phased small RNAs were found to be responsive to wounding or topping treatment. Targets of small RNAs were further surveyed by degradome sequencing.ConclusionsThe expression changes of miRNAs and phased small RNAs responsive to wounding or topping and identification of defense related targets for these small RNAs suggest that the inducible defense response in tobacco might be controlled by pathways involving small RNAs.

MicroRNA dynamics in a wild and cultivated species of Convolvulaceae exposed to drought stress

“…Similar to this observation, expression of miR477 was reported in leaves of wild progenitor of Cassava as compared to the cultivated ones (Chen et al 2015). miR477 was identified from Populus trichocarpa, Vitis vinifere and Nicotiana tabaccum (Lu Tang et al 2012). In P trichocarpa, miR477 is predicted to target a member of the GRAS gene family and a NAC-domain mRNA that are largely involved in developmental patterning (Lu et al 2005;Laufs et al 2004;Mallory et al 2004).…”

Sample sequencing of vascular plants demonstrates widespread conservation and divergence of microRNAs

“…10b). The Solanaceae sequence was only recently described in Nicotiana tabacum 31 and could not be found in versions of Fig. 10b reveals that the miR168-5p sequences 5 0 -UCGACUGGUGCAGA UCGGGAA-3 0 (present in C. rumphii and G. biloba), 5 0 -UCG AUUGGUGCAGAUCGGGAA-3 0 (C. rumphii, G. biloba and P. abies), 5 0 -UUGCUUGGUGCAGGUCGGGAA-3 0 (Z. marina) and 5 0 -UCGCUUGGUACAGGUCGGGAA-3 0 (Lactuca sativa) have relative high abundances, and cannot be found in the version 19 release of miRBase.…”

Regulation of Nicotine Biosynthesis by an Endogenous Target Mimicry of MicroRNA in Tobacco

“…Based on the small-RNA data generated from roots of control and topping-treated tobacco plants by deep sequencing in our previous study (Tang et al, 2012b), we identified a number of unique miRNAs that have not been reported previously, including four that were predicted to target genes (QPT1, QPT2, PMT2, and CYP82E4) involved in nicotine biosynthesis ( Fig. 1A; Supplemental Table S1).…”