Populus wulianensis mainly grows in hilly and sloped areas and has strong resistance to adversity. Previous transcriptome studies have shown that a WRKY gene PwuWRKY48 is expression-induced under drought stress. In this study, we aim to characterize the gene’s structure and investigate its role in plant drought resistance. The results show that PwuWRKY48 (1113 bp) belongs to a class IIc WRKY subfamily and it was determined as a nuclear localization protein. The gene promoter region contains a variety of cis-elements in relation to stress resistance. Under drought stress, PwuWRKY48 was expression-induced in leaves and stems, 29.7 and 16.6 times those before treatment, respectively. Overexpressing PwuWRKY48 lines were associated with increased activities of peroxidase (POD) and superoxide dismutase (SOD), 2.5 and 1.6 times higher than those of the wild type. While malondialdehyde content (MDA), superoxide anion radical (O₂^·−), and relative conductivity were decreased by 20%, 30%, and 21.3%, proline and chlorophyll contents increased by 37.5% and 11.2%, respectively. This indicates that PwuWRKY48 efficiently improved the drought tolerance of transgenic plants. PwuWRKY48 can be used as a gene resource for molecular breeding of plant drought resistance.

Introduction: This study aimed to project the potential distribution and habitat suitability dynamics of seven Astilbe species in China from 2000 to 2080. Methods: MaxEnt modelling was employed under the ACCESS-CM2 climate model and the SSP1-2.6 emission scenario, integrating field survey data, herbarium records, and 23 environmental variables, under the assumption of static soil and elevation conditions. Results: The results indicated that annual precipitation (bio12) and elevation (DEM) had the strongest statistical associations with the geographic distribution of the genus, while temperature and soil factors played secondary roles. Under current climatic conditions, the core suitable areas are concentrated mainly in Northeast and Southwest China, with pronounced interspecific spatial differentiation: A. rubra had the greatest suitable habitat area, whereas A. longicarpa had the smallest. Under future scenarios, the total suitable habitat area of the six species expanded, with A. longicarpa being the sole exception. The direction of centroid displacement varied among species: A. grandis , A. rivularis , A. longicarpa , and A. macroflora shifted towards higher latitudes, whereas A. chinensis , A. rubra , and A. macrocarpa shifted towards lower latitudes. At the genus level, habitat redistribution exhibited pronounced interspecific variation and directional heterogeneity. A. longicarpa and A. macroflora were identified as the most potentially vulnerable species, given their extremely restricted suitable areas, the absence of highly suitable habitat under current conditions, and their continued confinement largely to Taiwan Province. Discussion: For these range-restricted taxa, strengthened population monitoring within existing native ranges and assessments of ex situ conservation feasibility are warranted. These findings provide spatially explicit information to guide conservation planning for medicinal plant resources under climate change.