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Version 3.21
Publication Type J
Authors Chiang, C. P., W. C. Yim, Y. H. Sun, M. Ohnishi, T. Mimura, J. C. Cushman and H. E. Yen
Title Identification of Ice Plant (Mesembryanthemum crystallinum L.) MicroRNAs Using RNA-Seq and Their Putative Roles in High Salinity Responses in Seedlings
Source Frontiers in Plant Science
Author Keywords halophyte ice plant miRNA root growth salinity responses small RNA profile crassulacean acid metabolism epidermal bladder cells arabidopsis-thaliana salt tolerance superoxide-dismutase messenger-rna phosphoenolpyruvate carboxylase differential expression phosphate homeostasis stress responses
Abstract The halophyte Mesembryanthemum crystal/loom (common or crystalline ice plant) is a useful model for studying molecular mechanisms of salt tolerance. The morphology, physiology, metabolism, and gene expression of ice plant have been studied and large-scale analyses of gene expression profiling have drawn an outline of salt tolerance in ice plant. A rapid root growth to a sudden increase in salinity was observed in ice plant seedlings. Using a fluorescent dye to detect Na+, we found that ice plant roots respond to an increased flux of Na+ by either secreting or storing Na+ in specialized cells. High-throughput sequencing was used to identify small RNA profiles in 3-day-old seedlings treated with or without 200 rnM NaCI. In total, 135 conserved miRNAs belonging to 21 families were found. The hairpin precursor of 19 conserved mcr-miRNAs and 12 novel mcr-miRNAs were identified. After 6h of salt stress, the expression of most mcr-miRNAs showed decreased relative abundance, whereas the expression of their corresponding target genes showed increased mRNA relative abundance. The cognate target genes are involved in a broad range of biological processes: transcription factors that regulate growth and development, enzymes that catalyze miRNA biogenesis for the most conserved mcr-miRNA, and proteins that are involved in ion homeostasis and drought-stress responses for some novel mcr-miRNAs. Analyses of the functions of target genes revealed that cellular processes, including growth and development, metabolism, and ion transport activity are likely to be enhanced in roots under salt stress. The expression of eleven conserved miRNAs and two novel miRNAs were correlated reciprocally with predicted targets within hours after salt stress exposure. Several conserved miRNAs have been known to regulate root elongation, root apical meristem activity, and lateral root formation. Based upon the expression pattern of miRNA and target genes in combination with the observation of Na+ distribution, ice plant likely responds to increased salinity by using Na+ as an osmoticum for cell expansion and guard cell opening. Excessive Na+ could either be secreted through the root epidermis or stored in specialized leaf epidermal cells. These responses are regulated in part at the miRNA-mediated post-transcriptional level.
Author Address [Chiang, Chih-Pin; Yen, Hungchen E.] Natl Chung Hsing Univ, Dept Life Sci, Taichung, Taiwan. [Yim, Won C.; Cushman, John C.] Univ Nevada, Dept Biochem & Mol Biol, Reno, NV 89557 USA. [Sun, Ying-Hsuan] Natl Chung Hsing Univ, Dept Forestry, Taichung, Taiwan. [Ohnishi, Miwa; Mimura, Tetsuro] Kobe Univ, Grad Sch Sci, Kobe, Hyogo, Japan. Yen, HE (reprint author), Natl Chung Hsing Univ, Dept Life Sci, Taichung, Taiwan.; Cushman, JC (reprint author), Univ Nevada, Dept Biochem & Mol Biol, Reno, NV 89557 USA. jcushman@unr.edu; heyen@dragon.nchu.edu.tw
ISSN 1664-462X
ISBN 1664-462X
29-Character Source Abbreviation Front. Plant Sci.
Publication Date Aug
Year Published 2016
Volume 7
Digital Object Identifier (DOI) 10.3339/fpls.2016.01143
Unique Article Identifier WOS:000380982900001
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