Differential and dynamic regulation of miR398 in response to ABA and salt stress in Populus tremula and Arabidopsis thaliana

Abstract

MicroRNAs (miRNAs) are endogenous small RNAs of ~22 nucleotides (nt) that play a key role in down regulation of gene expression at the post-transcriptional level in plants and animals. Various studies have identified numerous miRNAs that were either up regulated or down regulated upon stress treatment. Here, we sought to understand the temporal regulation of miRNAs in different plant species under abscisic acid (ABA) and salt (NaCl) stress. Our results showed that the regulation of miR398 in response to ABA and salt stress was more dynamic in plants than previously reported. In poplars, miR398 was first induced upon 3-4 h of ABA or salt stress. However, this induction declined after 48 h and finally accumulated again over a prolonged stress (72 h). We referred to this kind of regulation as dynamic regulation. In contrast, such dynamic regulation of miR398 under salt stress was completely absent in Arabidopsis, in which miR398 was steadily and unidirectionally suppressed. Interestingly, ABA treatment caused a deviate dynamic regulation of miR398 in Arabidopsis, showing an opposite response as compared to that in poplars. We referred to the difference in regulation between Arabidopsis and poplars as differential regulation. Furthermore, the expression of the miR398 target, copper superoxide dismutase1 (CSD1), was in reverse correlation with the miR398 level, suggesting a control of this specific target expression predominantly by miR398 under abiotic stress. Together, these data consistently show a correlated regulation between miR398 and its representative target, CSD1, by ABA and salt stresses, and raise the possibility that regulation of miRNAs in plants is twofold: a dynamic regulation within a plant species and a differential regulation between different plant species.

Massive Analysis of Rice Small RNAs: Mechanistic Implications of Regulated MicroRNAs and Variants for Differential Target RNA Cleavage

“…However, our results showed that Os-miR397b.2 was induced by heat stress. This kind of differential regulation of a miRNA between different plant species was also reported in the case of miR398 (Jia et al, 2009). In poplar, miR398 was induced by ABA treatment or salt stress.…”

“…In poplar, miR398 was induced by ABA treatment or salt stress. However, the expression of miR398 in Arabidopsis was decreased by salt stress or by ABA treatment (Jagadeeswaran et al, 2009;Jia et al, 2009).…”

Transcriptional Regulation of ArabidopsisMIR168aandARGONAUTE1Homeostasis in Abscisic Acid and Abiotic Stress Responses

“…Recent evidence also uncovered the role of small RNA molecules in regulating plant stress responses (Sunkar, 2010;Khraiwesh et al, 2012). Microarray analysis and deep-sequencing data demonstrated that the accumulation of a number of miRNAs is affected by abiotic stresses (Sunkar and Zhu, 2004;Reyes and Chua, 2007;Zhou et al, 2007Zhou et al, , 2008Liu et al, 2008;Jia et al, 2009), implying a potential role of miRNAs in abiotic stress responses. In Arabidopsis, the expression of MIR395, MIR398, and MIR399 is induced by sulfate, copper, and phosphate deprivation, respectively, and their subsequent down-regulation of target genes is essential for nutrient reallocation (Fujii et al, 2005;Jagadeeswaran et al, 2009;Kawashima et al, 2009).…”

Non-coding RNAs Associated with Biotic and Abiotic Stresses in Plants

“…For instance miR160 and miR417 were down-regulated in response to abscisic acid in Arabidopsis, whereas miR169 and miR393 were up-regulated (Jia et al, 2009). There is a good example which shows multiple target of one miRNA.…”