Wildfire-associated changes in bacterial profiles of annual and perennial plants in the Amankaragai pine forest

Introduction Wildfires impact the soil- and plant-associated bacterial communities both directly through temperature shifts and indirectly by altering the physical, chemical, and biological properties. However, knowledge of post-fire soil- and plant-associated bacterial communities in Kazakhstan’s strongly continental climate, with pronounced seasonal variability, remains limited. The aim of this study is to investigate how wildfire shapes the diversity of plant-associated bacterial communities and their role in post-fire ecosystem resilience and recovery. Methods The study was conducted in the Amankaragai pine forest (Kostanay region, Kazakhstan) 2 years after wildfire. This study provides the first comprehensive analysis of the bulk soil, the rhizosphere, and the root bacterial microbiomes of Carex supina Willd. ex Wahlenb., Calamagrostis epigeios (L.) Roth, Conyza canadensis (L.) Cronquist, Chenopodium album L., and Lactuca serriola L., comparing control and burn sites. Results The wildfire significantly altered the composition of bacterial profiles across all plant-associated microbiomes. Beta diversity was affected across all plant species, while alpha diversity decreased in annual species but remained stable in perennials. Moreover, annual species showed a stronger disturbance response, with more differentially abundant taxa between control and burn sites, than perennial species. Burned sites were enriched with fire-associated bacterial taxa, including Arthrobacter , Pseudarthrobacter , and Massilia . Discussion Overall, the results reveal how wildfire alters the taxonomic diversity of soil bacterial communities, highlight differences in the bacterial microbiomes of annual and perennial plants, and provide a basis for assessing post-fire forest soil recovery.