Continuous Cropping Is Associated with Shifts in Strawberry Root-Associated Bacterial Communities and Predicted...

Area of Science:

• Microbiology
• Plant Science
• Soil Science

Background:

• Long-term strawberry cultivation can significantly alter plant-associated microbial communities.
• The specific responses of root-associated bacteria, encompassing both rhizoplane and endophytic communities, are not fully understood.
• Understanding these shifts is crucial for managing soil health and crop productivity in continuous strawberry farming.

Purpose of the Study:

• To compare the bacterial community composition, co-occurrence patterns, and predicted ecological functions in strawberry root-associated bacteria under short-term versus long-term cultivation.
• To investigate the impact of cultivation duration on microbial diversity and functional potential within the strawberry rhizosphere.
• To identify specific bacterial taxa and functions affected by prolonged strawberry cultivation.

Main Methods:

• Bacterial 16S rRNA gene sequencing (Illumina NovaSeq) was used to analyze root samples from short-term (4 months) and long-term (16 months) strawberry cultivation.
• Bioinformatic analyses included ASV-based diversity, taxonomic profiling, LEfSe for differential abundance, FastSpar for network analysis, and FAPROTAX for functional prediction.
• Six composite root samples were analyzed to capture robust community data.

Main Results:

• Long-term cultivation led to reduced bacterial ASV richness and a significant shift in community composition, with Actinobacteria declining and Proteobacteria/Bacteroidota increasing.
• Key genera such as *Streptomyces* and *Bradyrhizobium* decreased in abundance, while network analysis highlighted *Sphingobium*, *Bradyrhizobium*, and *Steroidobacter* as highly connected.
• Predicted functions shifted, showing decreases in chemoheterotrophy and nitrogen fixation, and increases in methylotrophy and aromatic compound degradation.

Conclusions:

• Cultivation duration is a significant factor driving compositional and functional shifts in strawberry root-associated bacterial communities.
• The observed depletion of Actinobacteria and *Bradyrhizobium* aligns with microbial indicators of continuous cropping obstacles.
• Further age-controlled studies are needed to validate these findings and understand the implications for sustainable strawberry cultivation.