MicroRNA172b-5p/trehalose-6-phosphate synthase module stimulates trehalose synthesis and microRNA172b-3p/AP2-like module accelerates flowering in barley upon drought stress

Abstract

MicroRNAs (miRNAs) are major regulators of gene expression during plant development under normal and stress conditions. In this study, we analyzed the expression of 150 conserved miRNAs during drought stress applied to barley ready to flower. The dynamics of miRNAs expression was also observed after rewatering. Target messenger RNA (mRNAs) were experimentally identified for all but two analyzed miRNAs, and 41 of the targets were not reported before. Drought stress applied to barley induced accelerated flowering coordinated by a pair of two differently expressed miRNAs originating from a single precursor: hvu-miR172b-3p and hvu-miR172b-5p. Increased expression of miRNA172b-3p during drought leads to the downregulation of four APETALA2(AP2)-like genes by their mRNA cleavage. In parallel, the downregulation of the miRNA172b-5p level results in an increased level of a newly identified target, trehalose-6-phosphate synthase, a key enzyme in the trehalose biosynthesis pathway. Therefore, drought-treated plants have higher trehalose content, a known osmoprotectant, whose level is rapidly dropping after watering. In addition, trehalose-6-phosphate, an intermediate of the trehalose synthesis pathway, is known to induce flowering. The hvu-miRNA172b-5p/trehalose-6-phosphate synthase and hvu-miRNA172b-3p/AP2-like create a module leading to osmoprotection and accelerated flowering induction during drought.

MiRNAs differentially expressed in vegetative and reproductive organs ofMarchantia polymorpha– insights into their expression pattern, gene structures and function

“…To date, the biological significance of plant miRNAs has been attributed mostly to conserved There are reports showing that microRNA* may be also a functional molecule and may accumulate in higher amounts than its microRNA during plant development and stress responses in angiosperms (Meng et al, 2011;Peng et al, 2013;Swida-Barteczka et al, 2023). Thus, MpMIR11865 gene may represent the first liverwort example of a gene encoding microRNA and microRNA* as functional molecules.…”

ABA-responsive small RNAs contribute to drought stress memory by regulating antioxidant activity and lignification

“…Several miRNAs have been identi ed in different plant species, including barley, mungbean, and Arabidopsis, that are involved in drought stress response. In barley, miR172b-3p and miR172b-5p were found to be differently expressed during drought stress, leading to accelerated owering and increased trehalose content (Swida- Barteczka, et al 2023). In mungbean, miR160, miR164, miR167, miR394, and miR398 were identi ed as potentially involved in the regulation of drought-responsive genes (Sanjeev Kumar 2022).…”

The Role of Drought and Temperature Stress in the Regulation of Flowering Time in Annuals and Perennials

“…miR172b-3p expression was upregulated under drought stress treatment, which suppressed the four AP2-like transcription factors in barley to accelerate flowering. The expression of miR172b-5p was inhibited under drought conditions; thus, trehalose-6-phosphate synthase (TPS), a key enzyme for trehalose biosynthesis targeted by miR172b-5p, was significantly accumulated to enhance drought tolerance in barley [107]. miR156, which is in the same age pathway regulating plant flowering as miR172, is also induced by drought stress and delays flowering of Arabidopsis and tobacco [138,143].…”