microRNA profiling of root tissues and root forming explant cultures in Medicago truncatula

To identify key miRNAs involved in root meristem formation in M. truncatula, deep sequencing was used to compare the miRNA populations dreived from four tissues. These were; root tip tissue, containing the root apical meristem, elongation zone tissue, root forming callus tissue and non-root forming callus tissue. We identified 83 previously reported miRNAs, 24 new to M. truncatula, in 44 families. For the first time in M. truncatula, members of conserved miRNA families mir165, miR181 and miR397 were found. Bioinformatic analysis identified 38 potential novel miRNAs. Many miRNAs were differentially expressed between tissues, particularly RFC and NRFC. Overall design: Examination and comparison of the microRNA population of four Medicago truncatula tissue types