Short-term salt and PEG stresses regulate expression of MicroRNA, miR159 in sugarcane leaves

Abstract

MicroRNAs (miRNAs) are involved in the regulation of stress-responsive gene expression and stress adaptation. Transcript expression of mature miR159 was studied in sugarcane leaves stressed for long-term (15 days) NaCl (150 mM) or iso-osmotic PEG 8000 (20% w/v) and for short period (up to 24 h) with NaCl (200 mM) or PEG (20% w/v). The results revealed no significant changes in transcript levels of the miRNA in response to the long-term stress however, short-term salt or PEG stress led to significant up-regulation over the control. Progressive increase in transcripts of the miRNA was observed under short-term PEG stress with exposure period. Using computational tools, various members of the MYB transcription factor family were predicted as the potential targets of miR159. The transcript expression of the MYB-related gene indicated up-regulation at 1 h of salt stress with concomitant slight downregulation of the miRNA. In addition, under short-term PEG stress, the transcript levels of MYB and miR159 were the opposite of each other, suggesting MYB as a potential target of miR159. To our knowledge, this is the first preliminary evidence on the involvement of miR159 in abiotic stress responses in sugarcane.