Convergence between splicing and miRNAs machinaries in plants.

CONTINO G; AGROFOGLIO, YAMILA CARLA; FRIXIONE LUCAS; FERA JULIANA; IGLESIAS, M.J.; MATEOS, JULIETA L

Congreso; RAFV Conference 2023 XXXIV Argentinian meeting of Plant Physiology; 2023

Plants adapt to the local environment by dynamically shaping their transcriptome. For this, post-transcriptional mechanisms play a key role. Alternative splicing, which generates several mature RNA isoforms from the same primary transcript, and microRNAs (miRNAs) that allow fine tuning gene expression in a fast and precise manner, have been shown to be important for a proper response of the plant to a changing environment. The proteins involved in both processes share similar functional characteristics, such as RNA recognition, RNA binding and RNA cutting. Therefore, there is a proposed link between small RNA biogenesis and RNA splicing, but the underlying mechanism of this cross-talk was not addressed in detail. The main objective of our work is to understand the integration between these machineries and to what extent the convergence of these two post-transcriptional mechanisms determines the final destination of the RNAs and the regulation of gene expression in plants. We performed a screening to evaluate the accumulation of different miRNAs in a series of mutants in splicing-related factors (SRFs). We found four SRFs that affect the production of miRNAs. We hypothethyse that SRF1, SRF2, SRF3 and SRF4 participate in the regulation of their biogenesis since genes structure of many miRNAs affected in those mutants have no introns neither located in introns of other genes. In addition, the overexpression of miRNA172 and miRNA319 that induces early flowering or crinkled leaves, respectively, showed in SRF1, SRF2, SRF3 and SRF4 mutants milder phenotypes compared to wild-type plants. These observations suggest a crosstalk between splicing and miRNA biogenesis that depends on at least four SRFs. In order to decipher the molecular mechanism, we plan to perform CoIP and CLIP-seq assays to determine which microprocessor component(s) or pre-miRNAs interact with the SRFs, respectively.