Flax Inorganic Phosphate Deficiency Responsive miRNAs

MicroRNAs (miRNAs) control a variety of biological processes and are involved in plant response to abiotic stress including phosphate starvation. Phosphate deficiency is one of the major limiting factors for crop yield. In the present work inorganic phosphate deficiency responsive miRNAs were identified in flax for the first time by high-throughput sequencing. Three conserved miRNA families (miR398, miR399 and miR408) were differentially expressed under inorganic phosphate starvation. In other plant species it was demonstrated that these miRNAs are involved in response to a combination of different stresses. In phosphate starvation conditions miR399 and miR408 are up-regulated but miR398 is differentially expressed. We found that in flax under inorganic phosphate starvation stress conditions expression level alterations for conserved miRNAs miR399 and miR408 were close to those in other plant species and for miR398 – to those in tomato but not in Arabidopsis. A better understanding of miRNAs stress regulatory functions would provide new tools for genetic improvement of stress tolerance in flax and other plants.