Biology subjects

Joon, R.

Publications and source records attributed to Joon, R..

4 recordsLinked to original sources

bioRxiv2024

MicroRNA Tae-miR1130p targets wheat ferroportin1 (TaFPN1) in the absence of iron-responsive element/iron-regulatory protein1 module

Ferroportin (FPN) belongs to the Major Facilitator Superfamily of transporters and is a known iron (Fe) exporter in humans, with orthologues also present in plant species. Human FPN is subjected to multi-level regulation at transcriptional, post-transcriptional, and post-translational levels. How plant FPNs are regulated remains to be explored. In the current study, we have characterized wheat FPN1, a plasma-membrane localized protein, for its role in Fe homeostasis. A spatial-temporal expression analysis of wheat FPN1 suggested that its tissue-specific expression is differentially upregulated during Fe deficiency conditions. Unlike human FPN, plant FPN lacks the necessary sites for hepcidin binding, thereby emphasizing the need to explore the transcriptional/post-transcriptional mode of regulation. The lack of Iron Responsive Elements (IRE) in TaFPN1 promoter suggests no direct regulation through the Iron Regulatory Protein (IRP) mechanism like in humans. Further, to explore the miRNA-mediated regulation, we identified Fe-regulated tae-miR1130b-3p capable of targeting TaFPN1 under in-vivo conditions. Transcript expression of tae-miR1130b-3p negatively correlates with the TaFPN1. This alternative regulation pathway suggests a complex network of interactions governing the expression of genes involved in iron homeostasis, highlighting the intricacies of cellular regulatory mechanisms. Altogether, the work will unravel the cellular and physiological role of wheat FPN and contribute to a comprehensive understanding of plant iron homeostasis.

plant biology↗

bioRxiv2023

System analysis of differentially expressed miRNAs in hexaploid wheat display tissue-specific regulatory role during Fe deficiency response

BackgroundIron (Fe) is an essential mineral element, and its deficiency in soil largely affects crop productivity. In plants, the molecular mechanisms underlying the genetic regulation of Fe deficiency responses have yet to be well understood. Specifically, microRNA (miRNA) mediated regulation of Fe deficiency response and its regulatory network is largely elusive. In the current work, we utilized a whole genome transcriptomic approach to identify the Fe deficiency-responsive miRNAs to understand the molecular mechanisms of Fe deficiency response in wheat seedlings. The study also identifies nine novel miRNAs putatively involved in Fe deficiency response. Further, the identified miRNAs showed tissue preferences relating them to differential mechanisms against Fe deficiency. ResultsIn the present study, we performed small RNA-targeted whole genome transcriptome analysis to identify the involvement of sRNAs in Fe deficiency response. The analysis identified 105 differentially expressed miRNAs corresponding to Fe deficiency response, among them, 9 miRNAs were found to be novel in this study. Interestingly, tissue-specific regulation of Fe deficiency response also participates through miRNA-mediated regulation. We identified 17 shoot specific miRNAs and 18 root-specific miRNAs with altered expression. We validated the tissue specificity of these miRNAs by stem-loop quantitative RT-PCR. Further, an attempt was made to predict their targets to speculate their participation in Fe deficiency response. This miRNA target prediction analysis suggested a few major targets of the identified miRNAs, such as multicopper oxidases, E3 ubiquitin ligases, GRAS family, and WRKY transcription factors previously known to play key roles in Fe homeostasis. Our analysis of selected miRNAs also confirmed a temporal regulation of the response. ConclusionThe first information generated here will classify the repository of wheat miRNAs (with few novel miRNAs) for their role in Fe deficiency response. Our work provides insights into miRNA-mediated regulatory pathways during Fe deficiency.

plant biology↗

bioRxiv2022

Transcriptome and biochemical analysis pinpoint multi-layered molecular processes associated with iron deficiency tolerance in hexaploid wheat

Iron (Fe) is an essential nutrient for plants that is indispensable for many physiological activities. Although few genotypes were identified with contrasting tolerance to Fe deficiency, the molecular insight into the distinct biochemical and transcriptional responses determining the trait is poorly known. This study aimed to identify the molecular and biochemical basis for the contrasting Fe deficiency tolerance in wheat genotype showing tolerance to Fe deficiency (cv. Kanchan-KAN) compared to susceptible (cv. PBW343-PBW) cultivar. Under Fe deficiency, the KAN show delayed chlorosis, high SPAD values and low malondialdehyde activity compared to PBW. The shoot transcriptomics studies show that a large set of genes for photosynthetic pathways were highly induced in PBW, suggesting its sensitivity to Fe deficiency. Although, under Fe deficiency, both the cultivars show distinct molecular re-arrangements, including high expression of genes involved in Fe uptake (including membrane transporters) and mobilization, the gene expression level was higher in KAN. Furthermore, the KAN cultivar also shows high ubiquitination activity in the shoot tissue suggesting a high turnover of proteins in the tolerant cultivar. These observations were also co-related with the high root phytosiderophores biosynthesis and its release that contributes to the enhanced Fe translocation index in KAN. Overall, our work provides the key link to understanding the mechanistic insight for the Fe deficiency tolerance in hexaploid wheat. This will enable wheat breeders to select genotypes for better Fe use efficiency for agriculture.

plant biology↗

bioRxiv2022

Asymmetric expression of homoeologous genes in wheat roots modulates the early phase of iron-deficiency signalling

Iron (Fe) limitation leads to dramatic changes in gene expression in plants, to induce iron uptake and mobilization, while at the same time restrict Fe-dependent metabolism and growth. Although transcriptional changes in response to Fe deficiency have recently been charted in wheat, this was performed at a stage when photosynthesis and growth were severely impacted, confounding primary and secondary responses. Here, we specifically uncover the transcriptional landscape of wheat roots during the early stages of the Fe deficiency response (4 and 8 days) and after Fe resupply. Root growth was significantly inhibited at day 4, but chlorosis only became apparent on day 8. The number of differentially expressed genes increased from 1386 on day 4 to 3538 on day 8, with an overlap of 2006 genes. Genes with dynamic changes in expression patterns include membrane transporters and transcription factors shown to be involved in Fe homeostasis in other plant species. Comparative analysis of the Fe deficiency response at 4, 8 and 20 days identified a core set of Fe-regulated genes. Analysis of the expression of homoeologs suggests an increase in induction bias at 8 days compared to 4 days particularly, A genome contributing high at 4 days and the A+D genomes at 8 days. Overall, our work will contribute towards fundamental knowledge of the Fe signalling networks in wheat and point to the interplay of the three sub-genomes in this hexaploid species to fine tune the transcriptional response.

plant biology↗