Analysis of physiological and miRNA responses to Pi deficiency in alfalfa (Medicago sativa L.)

Abstract

The induction of miR399 and miR398 and the inhibition of miR156, miR159, miR160, miR171, miR2111, and miR2643 were observed under Pi deficiency in alfalfa. The miRNA-mediated genes involved in basic metabolic process, root and shoot development, stress response and Pi uptake. Inorganic phosphate (Pi) deficiency is known to be a limiting factor in plant development and growth. However, the underlying miRNAs associated with the Pi deficiency-responsive mechanism in alfalfa are unclear. To elucidate the molecular mechanism at the miRNA level, we constructed four small RNA (sRNA) libraries from the roots and shoots of alfalfa grown under normal or Pi-deficient conditions. In the present study, alfalfa plants showed reductions in biomass, photosynthesis, and Pi content and increases in their root-to-shoot ratio and citric, malic, and succinic acid contents under Pi limitation. Sequencing results identified 47 and 44 differentially expressed miRNAs in the roots and shoots, respectively. Furthermore, 909 potential target genes were predicted, and some targets were validated by RLM-RACE assays. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed prominent enrichment in signal transducer activity, binding and basic metabolic pathways for carbohydrates, fatty acids and amino acids; cellular response to hormone stimulus and response to auxin pathways were also enriched. qPCR results verified that the differentially expressed miRNA profile was consistent with sequencing results, and putative target genes exhibited opposite expression patterns. In this study, the miRNAs associated with the response to Pi limitation in alfalfa were identified. In addition, there was an enrichment of miRNA-targeted genes involved in biological regulatory processes such as basic metabolic pathways, root and shoot development, stress response, Pi transportation and citric acid secretion.

Lolium perenne'de Fosfat Eksikliği Stresinde miRNA408’in Rolü: Üç Yıllık Tarla Çalışması

“…In the third year of the study, the hay yield of P2 and P3 decreased approximately three times compared to the control under phosphate deficiency stress. Studies have shown that phosphate deficiency results in decreases in photosynthesis, reduced shoot, leaf, and biomass (Li et al, 2018) which is consistent with the results of this study. Moreover, significant decreases were observed in third year compared to the previous years in P2, and P3 in hay yield.…”

“…miRs are known as regulators of many processes in plants against stress factors. Recent studies show that miRs can be involved with phosphate deficiency in several plant species (Zeng et al, 2016;Li et al, 2018;Ning et al, 2019). miR408 is one of the highly conserved miRNA family member in several plant species (Hajyzadeh et al, 2015).…”

Transcriptome-wide identification of novel circular RNAs in soybean in response to low-phosphorus stress

“…By acting as miRNA sponges and competing for endogenous mRNAs, circRNAs play crucial roles in regulating functional gene expression and transcription [46]. Many miRNAs have been reported to participate in the response to P deficiency in various plant species by regulating the expression of target genes, including miR399 [47][48][49][50], miR319 [51], miR156 [52], and miR159 [53]. For example, a recent study in maize revealed that the PILNCR1-miR399 regulatory module is important for LP tolerance [47].…”

Identification of Exogenous Nitric Oxide-Responsive miRNAs from Alfalfa (Medicago sativa L.) under Drought Stress by High-Throughput Sequencing

“…Muhammad Arshad et al found that miR156 improved the drought resistance of alfalfa by acting on WD40-2 [31]. In addition, salinity-regulated [32], fall dormancy-related [33], freezing stress-related [34], and Pi deficiency-related [35] miRNAs have been identified in Medicago sativa. The above results suggest that miRNA plays a key role in the metabolism of alfalfa.…”