Hydrogen peroxide-responsive miRNAs and their targets in wheat

MicroRNAs (miRNAs), regulating gene expression at post-transcriptional level are probably also involved in the redox control of growth and development. The aim of the present study was the identification of H2O2-responsive miRNAs and the determination of their function by looking for their possible target genes in wheat. By comparison of the miRNA transcript profile in control and H2O2-treated (0, 3, 6 h) wheat seedlings, 74 miRNAs with at least 1.5-fold difference in their expression were identified. Their target genes were determined by degradome sequencing, which are related to the redox and hormonal regulation, transcription, protein metabolism, cell proliferation and energy homeostasis indicating the coordinated re-progamming of growth and development by H2O2-responsive miRNAs during changes in the environment. Following the time-course of the changes (0, 1, 3, 6, 9, 12, 24 h) in the level of miRNAs and their target mRNAs by qRT-PCR in leaves of H2O2-treated wheat seedlings a direct relationship between them could not be always observed which shows that besides the local miRNA-dependent degradation of the target mRNAs, the miRNAs can be transported to/from other organs to regulate their targets