Continuous Cropping Is Associated with Shifts in Strawberry Root-Associated Bacterial Communities and Predicted Carbon–Nitrogen Functional Profiles

Abstract

Simple Summary This study investigated how cultivation duration influences root-associated bacterial communities in strawberry (cv. Dandong 99), focusing on combined rhizoplane and endophytic compartments. Using 16S rRNA (V4) amplicon sequencing, bacterial diversity, composition, co-occurrence networks, and predicted functions were compared between short-term (4 months) and long-term (16 months) cultivation. Long-term cultivation significantly reduced bacterial richness and altered community structure. Notably, Actinobacteria declined, while Proteobacteria and Bacteroidota increased. Several genera, including Streptomyces and Bradyrhizobium, decreased in abundance, despite some remaining central in network connectivity. Functional predictions suggested reduced capacities for chemoheterotrophy, nitrogen fixation, and chitinolysis, alongside increased methylotrophy and aromatic compound degradation. Overall, the results indicate that extended cultivation duration is associated with shifts in both the composition and potential function of root-associated bacterial communities, partially resembling microbial patterns linked to continuous cropping stress.