VvERF105 enhances drought resistance in grape through interaction with VvSnRK1

Drought stress severely restricts grape growth and yield. ERF105 is widely involved in plant developmental processes as well as responses to biotic and abiotic stresses. Nevertheless, existing studies of the ERF105 gene have primarily focused on cold and disease resistance, leaving its potential function in drought response largely unexplored. Therefore, investigating the role of ERF105 under drought conditions is crucial for understanding the molecular mechanisms of stress tolerance in grape and for breeding drought-resistant cultivars.

A VvERF105 gene was cloned from drought-resistant Vitis vinifera cv. 'Thompson Seedless', followed by sequence analysis, subcellular localization assay, and expression pattern analysis. A dual-target gene editing vector of VvERF105 was subsequently constructed and transformed into embryogenic calli of 'Thompson Seedless' via Agrobacterium-mediated genetic transformation. Gene-edited and wild type (WT) grapes were subjected to drought treatment. The biological function of VvERF105 under drought stress was determined by observing the plant growth status and stomatal aperture, measuring the proline and malondialdehyde (MDA) contents, antioxidant enzyme activities, and the expression levels of drought-related genes. In addition, proteins interacting with VvERF105 were screened and verified using yeast two-hybrid, bimolecular fluorescence complementation (BiFC), and co-immunoprecipitation (Co-IP) assays. Their interaction was further confirmed using in vitro phosphorylation assays.

VvERF105 is a stress-responsive gene localized in the nucleus. It responds to drought, cold, and high-temperature stresses and may act downstream of the ABA signaling pathway. VvERF105 mutant grapevine plants exhibited reduced resistance to drought stress. The edited lines exhibited smaller stomatal apertures, lower proline content, higher MDA content, and lower antioxidant enzyme activities compared to WT plants under drought stress. The expression levels of VvDREB2A, VvERD14, VvKIN2, VvNCED1, VvRD22, and VvRD29B were also significantly downregulated. VvSnRK1 was identified as an interacting protein of VvERF105 and interacts with it in a phosphorylation-independent manner.

VvERF105 is a nucleus-localized stress-responsive transcription factor that positively regulates grapevine drought stress responses. Its disruption significantly reduces drought resistance. Moreover, it interacts with the kinase VvSnRK1 in a phosphorylation-independent manner to mediate drought stress signaling in grapevines. The aforementioned results provide valuable genetic resources for molecular breeding of grapevines with enhanced drought resistance.