More and better genomic information just by changing the polyA

Root development and its response to environmental changes is crucial for whole plant adaptation. These responses include changes in transcript levels among other molecular processes. Polyadenylation of the 3´UTR is important for mRNA activity and stability. In this work, we show that the alternative polyadenylation (APA) events in mRNA is important for root development and responses to abiotic stresses such as salinity. We found a mutant with a lesion in FIP1 gene. FIP1 is a component of polyadenylation machinery, and mutation in this gene affects plant development, especially lateral root, cell division and elongation and response to different abiotic stresses. Salt treatment significantly increases the formation of new mRNA by changing the location of the poly(A), even to unusual sites as the non-canonical 5´-UTRs. We found that FIP1 is involved in coordinate the poly(A) site selection and usage frequency within these sites. Functional analyses of transcripts showing alternative polyadenylation in response to salt show an enrichment in ABA signaling, and response to stresses such as salt or cadmium genes, among others. Finally, correlating with this enrichment, we found that fip1-2 mutant is more tolerant to salt but hypersensitive to ABA or Cd. In conclusion, we propose that FIP1-mediated alternative polyadenylation is important for plant development and stress responses.