Distribution of Small RNAs Along Transposable Elements in Vitis vinifera During Somatic Embryogenesis

In the present study we have generated a parallel analysis of the 5' RNA ends (PARE) referred to polyadenylated RNAs in somatic embryos from in vitro culture of immature anthers of Vitis vinifera. PARE analysis include also a shortRNA analysis of same material. We have submitted the sRNAseq to mirPROOF and miRCAT (srna_workbench software at http://srna-workbench.cmp.uea.ac.uk) in order to recognize known and putative novel miRNAs, respectively that could be present in somatic embryos. In addition, aRNAs and PARE libraries were integrated in order to identify those 5' RNA ends that could be explained by sRNAs (i.e. identify transcripts that could be cleaved by sRNAs). We have used publicly available annotations and we gained a deep insight into the gene families and the transcriptional regulation mediated by miRNAs in V. vinifera somatic embryos. Gene expression is finely regulated to specific paralogues in gene families such as the NADPH-dependent diflavin oxidoreductase, Phosphoserine aminotransferase, Ethylene-responsive transcription factors,  glutathione S-transferase par C, just to name a few. We have indeed characterized at least 4,000 mRNA targets. Size fractionated small RNA from total RNA extracts of somatic Embryos cv. "Brachetto" were ligated to adapters, purified again and reverse transcribed. After PCR amplification the sample was subjected to Illumina high throughput pyrosequencing. The kit used is TrueSeq Small RNA kit, Illumina. Please see www.illumina.com for details of the sequencing technology. PARE libraries were generated starting from Poly(A) fraction. The protocol used have been previously described in German et al., 2009, Nature protocols. Please see www.illumina.com for details of the sequencing technology. Identification of regulatory non-coding RNAs in plant somatic embryos