Recent achievements in plant microRNA (miRNA), a large class of small and non-coding RNAs, are very exciting. A wide array of techniques involving forward genetic, molecular cloning, bioinformatic analysis, and the latest technology, deep sequencing have greatly advanced miRNA discovery. A tiny miRNA sequence has the ability to target single/multiple mRNA targets. Most of the miRNA targets are transcription factors (TFs) which have paramount importance in regulating the plant growth and development. Various families of TFs, which have regulated a range of regulatory networks, may assist plants to grow under normal and stress environmental conditions. This present review focuses on the regulatory relationships between miRNAs and different families of TFs like; NF-Y, MYB, AP2, TCP, WRKY, NAC, GRF, and SPL. For instance NF-Y play important role during drought tolerance and flower development, MYB are involved in signal transduction and biosynthesis of secondary metabolites, AP2 regulate the floral development and nodule formation, TCP direct leaf development and growth hormones signaling. WRKY have known roles in multiple stress tolerances, NAC regulate lateral root formation, GRF are involved in root growth, flower, and seed development, and SPL regulate plant transition from juvenile to adult. We also studied the relation between miRNAs and TFs by consolidating the research findings from different plant species which will help plant scientists in understanding the mechanism of action and interaction between these regulators in the plant growth and development under normal and stress environmental conditions.

microRNAs (miRNAs) are well known as major players in mammalian and plant genetic systems that act by regulating gene expression at the post-transcriptional level. These tiny molecules can regulate target genes (mRNAs) through either cleavage or translational inhibition. Recently, the discovery of plant-derived miRNAs showing cross-kingdom abilities to regulate mammalian gene expression has prompted exciting discussions among researchers. After being acquired orally through the diet, plant miRNAs can survive in the digestive tract, enter the circulatory system, and regulate endogenous mRNAs. Here, we review current knowledge regarding the cross-kingdom mechanisms of plant miRNAs, related controversies, and potential applications of these miRNAs in dietary therapy, which will provide new insights for plant miRNA investigations related to health issues in humans.

Background Persicaria minor (kesum) is an herbaceous plant with a high level of secondary metabolite compounds, particularly terpenoids. These terpenoid compounds have well-established roles in the pharmaceutical and food industries. Although the terpenoids of P. minor have been studied thoroughly, the involvement of microRNA (miRNA) in terpenoid regulation remains poorly understood and needs to be explored. In this study, P. minor plants were inoculated with the pathogenic fungus Fusarium oxysporum for terpenoid induction. Result SPME GC-MS analysis showed the highest terpenoid accumulation on the 6th day post-inoculation (dpi) compared to the other treatment time points (0 dpi, 3 dpi, and 9 dpi). Among the increased terpenoid compounds, α-cedrene, valencene and β-bisabolene were prominent. P. minor inoculated for 6 days was selected for miRNA library construction using next generation sequencing. Differential gene expression analysis showed that 58 miRNAs belonging to 30 families had significantly altered regulation. Among these 58 differentially expressed genes (DEGs), 33 miRNAs were upregulated, whereas 25 miRNAs were downregulated. Two putative novel pre-miRNAs were identified and validated through reverse transcriptase PCR. Prediction of target transcripts potentially involved in the mevalonate pathway (MVA) was carried out by psRobot software, resulting in four miRNAs: pmi-miR530, pmi-miR6173, pmi-miR6300 and a novel miRNA, pmi-Nov_13. In addition, two miRNAs, miR396a and miR398f/g, were predicted to have their target transcripts in the non-mevalonate pathway (MEP). In addition, a novel miRNA, pmi-Nov_12, was identified to have a target gene involved in green leaf volatile (GLV) biosynthesis. RT-qPCR analysis showed that pmi-miR6173, pmi-miR6300 and pmi-nov_13 were downregulated, while miR396a and miR398f/g were upregulated. Pmi-miR530 showed upregulation at 9 dpi, and dynamic expression was observed for pmi-nov_12. Pmi-6300 and pmi-miR396a cleavage sites were detected through degradome sequence analysis. Furthermore, the relationship between miRNA metabolites and mRNA metabolites was validated using correlation analysis. Conclusion Our findings suggest that six studied miRNAs post-transcriptionally regulate terpenoid biosynthesis in P. minor . This regulatory behaviour of miRNAs has potential as a genetic tool to regulate terpenoid biosynthesis in P. minor . Electronic supplementary material The online version of this article (10.1186/s12864-019-5954-0) contains supplementary material, which is available to authorized users.

MicroRNA (miRNA) is regarded as a prominent genetic regulator, as it can fine-tune an entire biological pathway by targeting multiple target genes. This characteristic makes miRNAs promising therapeutic tools to reinstate cell functions that are disrupted as a consequence of diseases. Currently, miRNA replacement by miRNA mimics and miRNA inhibition by anti-miRNA oligonucleotides are the main approaches to utilizing miRNA molecules for therapeutic purposes. Nevertheless, miRNA-based therapeutics are hampered by major issues such as off-target effects, immunogenicity, and uncertain delivery platforms. Over the past few decades, several innovative approaches have been established to minimize off-target effects, reduce immunostimulation, and provide efficient transfer to the target cells in which these molecules exert their function. Recent achievements have led to the testing of miRNA-based drugs in clinical trials, and these molecules may become next-generation therapeutics for medical intervention. Despite the achievement of exciting milestones, the dosage of miRNA administration remains unclear, and ways to address this issue are proposed. Elucidating the current status of the main factors of therapeutic miRNA would allow further developments and innovations to achieve safe therapeutic tools. This article is categorized under: RNA in Disease and Development > RNA in Disease Regulatory RNAs/RNAi/Riboswitches > RNAi: Mechanisms of Action K E Y W O R D S artificial miRNA, clinical trials, miRNA inhibition therapy, miRNA replacement therapy, miRNA therapeutics 1 | INTRODUCTION MicroRNAs (miRNAs) are noncoding RNAs 20 nucleotides in length that exist in mammals, plants, and viruses.According to miRBase version 22, the human genome is estimated to contain 2300 true human mature miRNAs, 1115 of which are currently annotated (Alles et al., 2019). Each miRNA can repress from ten to hundreds of genes, regulating almost every cellular and metabolic process (Friedman et al., 2009;Fuchs Wightman et al., 2018;Kilikevicius et al., 2021). miRNA has been recognized as an essential molecule for gene regulation since its discovery in 1993 (Lee et al., 1993). miRNA is synthesized through either canonical or noncanonical pathways. In the canonical pathway, the

Persicaria minor (kesum) is an important medicinal plant and commonly found in southeast countries; Malaysia, Thailand, Indonesia, and Vietnam. This plant is enriched with a variety of secondary metabolites (SMs), and among these SMs, terpenoids are in high abundance. Terpenoids are comprised of many valuable biomolecules which have well-established role in agriculture and pharmaceutical industry. In P. minor, for the first time, we have generated small RNAs data sets, which can be used as tool in deciphering their roles in terpenoid biosynthesis pathways. Fungal pathogen, Fusarium oxysporum was used as elicitor to trigger SMs biosynthesis in P. minor. Raw reads and small RNA analysis data have already been deposited at GenBank under the accessions; SRX2645684 (Fusarium-treated), SRX2645685 (Fusarium-treated), SRX2645686 (mock-infected), and SRX2645687 (mock-infected).

Purpose of Review Hexavalent chromium, Cr(VI), and trivalent chromium, Cr(III), are two chromium compounds with practical importance due to their high occurrence and solubility in the environment. Current Cr(VI) treatment techniques involve chemical reduction of Cr(VI) to Cr(III), which posed serious threat to workers and environment notably from long exposure and toxic fumes.Recent Findings Numerous reports have demonstrated the feasibility of using biological processes for the treatment of Cr(VI) industrial effluents by either pure culture or a consortium of Cr(VI)-reducing bacteria, with various degrees of success. Among issues to be considered include high cost of nutrient for the bacteria, low Cr resistant-reducing ability of environmental isolates, difficulty in scaling up finding in the laboratory to pilot scale and on-site application as well as the understanding on the dynamic underlying mechanisms for bacterial Cr(VI) reduction. Summary This review highlights cytotoxicity and genotoxicity properties of Cr(VI), which form the biggest motivation for continuous development in the field of Cr(VI) treatment technologies, latest finding in aerobic and anaerobic bacterial reduction of Cr(VI), operational challenges for bacterial Cr(VI) reduction, and some examples for laboratory-scale and pilot-scale evaluation of free and immobilized (biofilm) cells of Cr(VI) resistant-reducing bacteria.

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