title: MicroRNAs in metal stress: specific roles or secondary responses?
abstract: In plants, microRNAs (miRNAs) control various biological processes by negatively regulating the expression of complementary target genes, either (1) post-transcriptionally by cleavage or translational inhibition of target mRNA, or (2) transcriptionally by methylation of target DNA. Besides their role in developmental processes, miRNAs are main players in stress responses, including metal stress responses. Exposure of plants to excess metal concentrations disturbs the cellular redox balance and enhances ROS accumulation, eventually leading to oxidative damage or signaling. Plants modify their gene expression by the activity of miRNAs in response to metal toxicity to regulate (1) complexation of excess metals, (2) defense against oxidative stress and (3) signal transduction for controlling various biological responses. This review focuses on the biogenesis, working mechanisms and functioning of miRNAs in plants. In a final part, our current knowledge on the regulatory roles of miRNAs in plant metal stress responses is highlighted, and whether stress-regulated miRNAs have specific roles or are secondary consequences is discussed.
authors: Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, Diepenbeek 3590, Belgium. ann.cuypers@uhasselt.be.
authors: Heidi
authors: H
authors: Gielen
authors: Tony
authors: T
authors: Remans
authors: Jaco
authors: J
authors: Vangronsveld
authors: Ann
authors: A
authors: Cuypers
mesh_terms: D019175:DNA Methylation; D018744:DNA, Plant / Q000235:genetics / Q000378:metabolism*; D008670:Metals / Q000494:pharmacology*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D010944:Plants / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism*
chemical_list: D018744:DNA, Plant; D008670:Metals; D035683:MicroRNAs; D018749:RNA, Plant