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

Cadmium (Cd), 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 Cd into the food chain, making it an effective option for remediating Cdcontaminated soils. While previous researches have extensively examined the gene expression responses of cotton to Cd 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 Cd-tolerant cotton cultivar XM and the Cd-sensitive cotton cultivar ZM24 under Cd 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 Cd stress. Overall, our findings suggest that newly identified miRNAs and their corresponding target genes in cotton may contribute to enhance tolerance to Cd stress through multiple mechanisms, facilitating the breeding of superior cotton cultivars with enhanced tolerance to Cd toxicity.