DNA-binding with one finger (Dof) proteins comprise a large family that play central roles in stress tolerance by regulating the expression of stress-responsive genes via the DOFCORE element or by interacting with other regulatory proteins. Although the Dof TF has been identified in a variety of species, its systemic analysis in potato (Solanum tuberosum L.) is lacking and its potential role in abiotic stress responses remains unclear. A total of 36 potential Dof genes in potato were examined at the genomic and transcriptomic levels in this work. Five phylogenetic groups can be formed from these 36 Dof proteins. An analysis of cis-acting elements revealed the potential roles of Dofs in potato development, including under numerous abiotic stress conditions. The cycling Dof factors (CDFs) might be the initial step in the abiotic stress response signaling cascade. In potato, five CDFs (StCDF1/StDof19, StCDF2/StDof4, StCDF3/StDof11, StCDF4/StDof24, and StCDF5/StDof15) were identified, which are homologs of Arabidopsis CDFs. The results revealed that these genes were engaged in a variety of abiotic reactions. Moreover, an expression analysis of StDof genes in two potato cultivars (‘Long10′ (drought tolerant) and ‘DXY’ (drought susceptible)) of contrasting tolerances under drought stress was carried out. Further, a regulatory network mediated by lncRNA and its target Dofs was established. The present study provides fundamental knowledge for further investigation of the roles of Dofs in the adaptation of potato to drought stress, aiming to provide insights into a viable strategy for crop improvement and stress-resistance breeding.

Coordinated transcriptional regulation of stress-responsive genes orchestrated by a complex network of transcription factors (TFs) and the reprogramming of metabolism ensure a plant’s continued growth and survival under adverse environmental conditions (e.g., abiotic stress). DNA-binding with one finger (Dof) proteins, a group of plant-specific TF, were identified as one of several key components of the transcriptional regulatory network involved in abiotic stress responses. In many plant species, Dofs are often activated in response to a wide range of adverse environmental conditions. Dofs play central roles in stress tolerance by regulating the expression of stress-responsive genes via the DOFCORE element or by interacting with other regulatory proteins. Moreover, Dofs act as a key regulatory hub of several phytohormone pathways, integrating abscisic acid, jasmonate, SA and redox signaling in response to many abiotic stresses. Taken together, we highlight a unique role of Dofs in hormone and stress signaling that integrates plant response to adverse environmental conditions with different aspects of plant growth and development.

Stomata are specialized portals in plant leaves to modulate water loss from plants to the atmosphere by control of the transpiration, thereby determining the water-use efficiency and drought resistance of plants. Despite that the stomata developmental progression is well-understood at the molecular level, the experimental evidence that miRNA regulates stomata development is still lacking, and the underlying mechanism remains elusive. This study demonstrates the involvement of stu-miR827 in regulating the drought tolerance of potato due to its control over the leaf stomatal density. The expression analysis showed that stu-miR827 was obviously repressed by drought stresses and then rapidly increased after rewatering. Suppressing the expression of stu-miR827 transgenic potato lines showed an increase in stomatal density, correlating with a weaker drought resistance compared with wildtype potato lines. In addition, StWRKY48 was identified as the target gene of stu-miR827, and the expression of StWRKY48 was obviously induced by drought stresses and was greatly upregulated in stu-miR827 knockdown transgenic potato lines, suggesting its involvement in the drought stress response. Importantly, the expression of genes associated with stomata development, such as SDD (stomatal density and distribution) and TMM (too many mouths), was seriously suppressed in transgenic lines. Altogether, these observations demonstrated that suppression of stu-miR827 might lead to overexpression of StWRKY48, which may contribute to negatively regulating the drought adaptation of potato by increasing the stomatal density. The results may facilitate functional studies of miRNAs in the process of drought tolerance in plants.