MicroRNAs Are Intensively Regulated during Induction of Somatic Embryogenesis in Arabidopsis.
Several genes encoding transcription factors (TFs) were indicated to have a key role in the induction of somatic embryogenesis (SE), which is triggered in the somatic cells of plants. In order to further explore the genetic regulatory network that is involved in the embryogenic transition induced in plant somatic cells, micro-RNA (miRNAs) molecules, the products ofMIRNA(MIR) genes and the common regulators of TF transcripts, were analyzed in an embryogenic culture ofArabidopsis thaliana. In total, the expression of 190 genes of the 114MIRNAfamilies was monitored during SE induction and the levels of the primary (pri-miRNAs) transcripts vs. the mature miRNAs were investigated. The results revealed that the majority (98%) of theMIRgenes were active and that most of them (64%) were differentially expressed during SE. A distinct attribute of theMIRexpression in SE was the strong repression ofMIRtranscripts at the early stage of SE followed by their significant up-regulation in the advanced stage of SE. Comparison of the mature miRNAs vs. pri-miRNAs suggested that the extensive post-transcriptional regulation of miRNA is associated with SE induction. Candidate miRNA molecules of the assumed function in the embryogenic response were identified among the mature miRNAs that had a differential expression in SE, including miR156, miR157, miR159, miR160, miR164, miR166, miR169, miR319, miR390, miR393, miR396, and miR398. Consistent with the central role of phytohormones and stress factors in SE induction, the functions of the candidate miRNAs were annotated to phytohormone and stress responses. To confirm the functions of the candidate miRNAs in SE, the expression patterns of the mature miRNAs and their presumed targets were compared and regulatory relation during SE was indicated for most of the analyzed miRNA-target pairs. The results of the study contribute to the refinement of the miRNA-controlled regulatory pathways that operate during embryogenic induction in plants and provide a valuable platform for the identification of the genes that are targeted by the candidate miRNAs in SE induction.
Department of Genetics, Faculty of Biology and Environmental Protection, University of Silesia Katowice, Poland.
Katarzyna
K
Szyrajew
Department of Gene Expression, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan, Poland.
Dawid
D
Bielewicz
Department of Gene Expression, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan, Poland.
Jakub
J
Dolata
Department of Genetics, Faculty of Biology and Environmental Protection, University of Silesia Katowice, Poland.
Anna M
AM
Wójcik
Department of Genetics, Faculty of Biology and Environmental Protection, University of Silesia Katowice, Poland.
Katarzyna
K
Nowak
Department of Genetics, Faculty of Biology and Environmental Protection, University of Silesia Katowice, Poland.
Aleksandra
A
Szczygieł-Sommer
Department of Gene Expression, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan, Poland.
Zofia
Z
Szweykowska-Kulinska
Department of Gene Expression, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan, Poland.
Artur
A
Jarmolowski
Department of Genetics, Faculty of Biology and Environmental Protection, University of Silesia Katowice, Poland.
Małgorzata D
MD
Gaj
Arabidopsis; MIRNA genes; gene expression; mature miRNA; pri-miRNA; somatic embryogenesis