Uncovering miRNA-mRNA regulatory modules of cotton in response to cadmium stress

Cadmium (Cd²⁺), a non-essential heavy metal for plant, adversely effects on crop productivity and food safety. Cotton, predominantly cultivated as a non-food crop, offers the advantage of not transferring Cd²⁺ into the food chain, making it an effective option for remediating Cd²⁺contaminated soils. While previous researches have extensively examined the gene expression responses of cotton to Cd²⁺ stress, insights at the post-transcriptional level remain limited. In this study, a comprehensive methodology was employed, incorporating miRNA sequencing, degradomics, and RNA sequencing, to investigate the responses of the Cd²⁺-tolerant cotton cultivar XM and the Cd²⁺-sensitive cotton cultivar ZM24 under Cd²⁺ exposure. The analysis revealed that these the identified miRNA-target gene pairs predominantly influence various biological processes, including light signaling, cell wall biogenesis, abiotic stress responses, transportation, and hormone signaling pathways in response to Cd²⁺ stress. Overall, our findings suggest that newly identified miRNAs and their corresponding target genes in cotton may contribute to enhance tolerance to Cd²⁺ stress through multiple mechanisms, facilitating the breeding of superior cotton cultivars with enhanced tolerance to Cd²⁺ toxicity.