MicroRNAs Are Involved in Regulating Plant Development and Stress Response through Fine-Tuning of TIR1/AFB-Dependent Auxin Signaling

Abstract

Auxin, primarily indole-3-acetic acid (IAA), is a versatile signal molecule that regulates many aspects of plant growth, development, and stress response. Recently, microRNAs (miRNAs), a type of short non-coding RNA, have emerged as master regulators of the auxin response pathways by affecting auxin homeostasis and perception in plants. The combination of these miRNAs and the autoregulation of the auxin signaling pathways, as well as the interaction with other hormones, creates a regulatory network that controls the level of auxin perception and signal transduction to maintain signaling homeostasis. In this review, we will detail the miRNAs involved in auxin signaling to illustrate its in planta complex regulation.

Transcriptional Regulation of zma-MIR528a by Action of Nitrate and Auxin in Maize

“…For instance, treatments with indoleacetic acid (IAA) promote transcription of ath- MIR393b in aerial seedling organs [ 55 ]. Furthermore, miR393 also accumulates two hours after incubation in 5 mM potassium nitrate solution and induces target down-regulation [ 56 , 57 ]. Interestingly, during SE induction in A. thaliana, expression of MIR393a and MIR393b increase to enable explant sensitivity to auxins [ 58 ], which mirrors the miR528 response in maize SE.…”

Perception, Transduction and Crosstalk of Auxin and Cytokinin Signals

“… Venn diagram summarizing the IJMS Special Issue “Perception, Transduction and Crosstalk of Auxin and Cytokinin Signals” [ 2 , 5 , 8 , 10 , 13 , 15 , 16 , 17 , 19 , 21 ]. Areas associated with cytokinin and auxin are marked in green and pink, respectively; the overlapping region corresponds to both hormones.…”

“…The genes involved in auxin signaling are targeted by multiple miRNAs, and some of these genes are directly involved in growth and stress reactions. In the informative overview by a Chinese team mainly from Gansu Agricultural University and the Institute of Soil Sciences [ 21 ], the miRNA-mediated regulation of auxin signaling is divided into two types: (i) the direct targeting of the genes involved in the auxin signaling pathway, including TIR1/AFBs , ARF and AUX/IAA ; (ii) the modulation of the free auxin content via the indirect regulation of auxin biosynthesis, metabolism and transport. The authors consider the latest studies on the miRNA-mediated regulation of the auxin pathway in the dicot Arabidopsis and the monocot rice, as well as new findings in other species, in order to provide a comprehensive picture of the important roles that miRNAs play in auxin signaling.…”

Genome-wide identification of auxin-responsive microRNAs in the poplar stem

“…Auxin plays a central role in regulating the initiation and proliferation of vascular cambium and differentiation of the cambial derivative cells during wood formation [1]. A subset of miRNAs are shown to target genes involved in auxin homeostasis and signaling [14]. In Arabidopsis, miR393 and miR847 enhance auxin signaling by cleaving the mRNAs of TRANSPORT INHIBITOR RESPONSE 1/AUXIN SIGNALING F-BOX PROTEIN 2, 3 (TIR1/AFB2, 3) and INDOLE ACETIC ACID 28 (IAA28), respectively [15,16].…”