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Type: Journal article
Title: Transcriptional regulation of Arabidopsis MIR168a and ARGONAUTE1 homeostasis in abscisic acid and abiotic stress responses
Author: Li, W.
Cui, X.
Meng, Z.
Huang, X.
Xie, Q.
Wu, H.
Jin, H.
Zhang, D.
Liang, W.
Citation: Plant Physiology, 2012; 158(3):1279-1292
Publisher: American Society of Plant Biologists
Issue Date: 2012
ISSN: 0032-0889
Statement of
Wei Li, Xiao Cui, Zhaolu Meng, Xiahe Huang, Qi Xie, Heng Wu, Hailing Jin, Dabing Zhang, and Wanqi Liang
Abstract: The accumulation of a number of small RNAs in plants is affected by abscisic acid (ABA) and abiotic stresses, but the underlying mechanisms are poorly understood. The miR168-mediated feedback regulatory loop regulates ARGONAUTE1 (AGO1) homeostasis, which is crucial for gene expression modulation and plant development. Here, we reveal a transcriptional regulatory mechanism by which MIR168 controls AGO1 homeostasis during ABA treatment and abiotic stress responses in Arabidopsis (Arabidopsis thaliana). Plants overexpressing MIR168a and the AGO1 loss-of-function mutant ago1-27 display ABA hypersensitivity and drought tolerance, while the mir168a-2 mutant shows ABA hyposensitivity and drought hypersensitivity. Both the precursor and mature miR168 were induced under ABA and several abiotic stress treatments, but no obvious decrease for the target of miR168, AGO1, was shown under the same conditions. However, promoter activity analysis indicated that AGO1 transcription activity was increased under ABA and drought treatments, suggesting that transcriptional elevation of MIR168a is required for maintaining a stable AGO1 transcript level during the stress response. Furthermore, we showed both in vitro and in vivo that the transcription of MIR168a is directly regulated by four abscisic acid-responsive element (ABRE) binding factors, which bind to the ABRE cis-element within the MIR168a promoter. This ABRE motif is also found in the promoter of MIR168a homologs in diverse plant species. Our findings suggest that transcriptional regulation of miR168 and posttranscriptional control of AGO1 homeostasis may play an important and conserved role in stress response and signal transduction in plants.
Keywords: Arabidopsis
Abscisic Acid
Arabidopsis Proteins
RNA, Plant
Adaptation, Physiological
Signal Transduction
Gene Expression Regulation, Plant
Conserved Sequence
Basic-Leucine Zipper Transcription Factors
Promoter Regions, Genetic
Stress, Physiological
Transcriptional Activation
Argonaute Proteins
Nucleotide Motifs
Rights: © 2012 American Society of Plant Biologists
DOI: 10.1104/pp.111.188789
Appears in Collections:Agriculture, Food and Wine publications
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