Regulation of plant development by a non-coding RNA transcribed by the bidiectional HaWRKY6 promoter

GAGLIARDI DELFINA; TOMASSI ARIEL HERNÁN; MANAVELLA PABLO ANDRÉS

Congreso; LII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

AbstractMicroRNAs (miRNAs) are small 21-nucleotide RNAs that post-transcriptionally regulate gene expression, controlling development and adaptation of multicellular organisms to the environment. The miRNA-mediated regulation of transcription factors is critical for the correct response to stress conditions. For instance, the miR396-mediated regulation of HaWRKY6 controls the sunflower response to temperatures. We observed that Arabidopsis thaliana plants expressing a reporter gene under the control of the HaWRKY6 promoter present an unusual phenotype accompanied with a reduction in the miRNAs levels. We discovered that this promoter works bidirectionally, it transcribes HaWRKY6 in sense and a non-coding RNA (ncRNA) in anti-sense. This ncRNA, the cause of the phenotype, adopt a fold back structure characteristic of miRNA precursors. Small RNA Sequencing (sRNA-Seq), allowed us to identify a 21 nt small RNA derived from this ncRNA. Transcriptomic analysis of plants expressing such ncRNA is allowing us to identify the potential targets of this ncRNA that could explain the phenotype. Interestingly, we have observed that the phenotype triggered by this ncRNA disappear with the successive plants generations, unless transformed into siRNA deficient mutants, suggesting that this region of the HaWRKY6 undergoes epigenetic silencing, fact confirmed by bi-sulfite treatment in sunflower.