IDENTIFICATION AND ANALYSIS OF DIFFERENTIALLY EXPRESSED miRNAs RELATED TO SEEDLING DEVELOPMENT IN THE ARABIDOPSIS THALIANA CYP71 MUTANT

CYCLOPHILIN71 (AtCYP71), a multidomain cyclophilin, has been demonstrated to participate in many aspects of development in Arabidopsis thaliana. Loss of AtCYP71 function results in pleiotropic developmental phenotypes including defects in shoot apical meristem (SAM), root apical meristem (RAM), leaf morphology as well as floral development. Previous studies have reported that microRNAs (miRNAs) play critical roles in plant development. However, to date, development-related miRNAs associated with AtCYP71 have rarely been reported. In our study, by employing small RNA (sRNA) and degradome sequencing, we surveyed development-related miRNAs and their targets in the wild type and cyp71 mutant. We identified 253 known miRNAs in total through high-throughput sequencing of two sRNA libraries and degradome libraries constructed from 10-day-old seedlings of the wild type and cyp71 mutant. Of these, 38 known miRNAs (16 increased and 22 decreased) were differentially expressed with normalized reads larger than 100. Via degradome analysis, 337 transcripts of 192 target genes targeted by 95 known miRNAs, including miR164, miR393, miR171, miR172 and miR824, were detected. Further functional analysis suggested that several identified targets, such as NAC1, AFB1, SCL6 & SCL23, TOE2 and AGL16, were transcription factors that function in shoot meristem and lateral organ development together with nutrient metabolism. Overall, our results indicated that the disruption of AtCYP71 function contributes to altering the expression of some key miRNAs that target corresponding key genes that play critical roles in seedling development together with nutrient metabolism.