Transcriptomics Data Mining to Identify Novel Regulatory Genes of Iron Uptake in Drought-Stressed Wheat.

Understanding the molecular crosstalk between drought and iron (Fe) homeostasis is crucial for developing drought-tolerant wheat cultivars with enhanced nutrient quality. In this study, transcriptomic data mining identified 23,271 and 5933 differentially expressed genes (DEGs) under drought and Fe deficiency, respectively, with 2479 DEGs in response to both stresses. Notably, this overlapping set included significant numbers of genes encoding transcription factors (TFs) (149 genes), Fe homeostasis components (274 genes), and those involved in phytohormones pathways (245 genes), particularly the abscisic acid (ABA) pathway. Gene Ontology (GO) analysis revealed specific and commonly affected biological processes, such as response to abiotic stimulus and heme binding. Furthermore, co-expression network analysis revealed modules highly enriched with genes involved in transcriptional regulation and Fe uptake, enabling the identification of key hub regulatory genes, belonging to the MYB, NAC, BHLH, and AP2/ERF families, involved in the shared stress response. Finaly, the expression of a set of candidate TF-encoding genes was validated using qRT-PCR in durum wheat under drought and Fe starvation, providing a detailed overview of the possible shared regulatory mechanisms linking drought and Fe deficiency responses.