Soil bacterial communities are influenced by soil chemical characteristics and dispersal limitation in commercial strawberry production systems

Authors: Leblanc, Nicholas; Gebben, Samantha

Submitted to: Plant-Environment Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/2022
Publication Date: 1/11/2023
Citation: LeBlanc, N.R., Gebben, S. 2023. Soil bacterial communities are influenced by soil chemical characteristics and dispersal limitation in commercial strawberry production systems. Plant-Environment Interactions. 4(1):11-22. https://doi.org/10.1002/pei3.10099.
DOI: https://doi.org/10.1002/pei3.10099

Interpretive Summary: Diverse groups of bacteria that live in soil can influence the health of fruit crops like strawberry. Bacteria can alter the availability of soil nutrients that plants need to grow as well as suppress and cause soilborne plant diseases. Even though it is widely recognized that bacteria are important for strawberry health, factors influencing bacterial communities in commercial strawberry production systems are poorly studied and understood. This lack of knowledge prevents developing new ways to manage the activity of bacteria in soil to improve strawberry production. In this study, bacterial communities were analyzed from standardized plots within two different commercial strawberry production systems in the Salinas Valley, CA. Bacteria were identified in 72 soil samples using DNA sequencing. In addition, carbon, nitrogen, and pH were measured for each soil sample. Statistical analyses showed that soil pH and nitrogen influenced bacteria in soil in only one of three sampled plots. In addition, the types of bacteria in two plots at one of the two locations could be predicted based on spatial location of where soil samples were originally collected. This study suggests factors influencing bacterial communities in soil are not consistent among different strawberry production systems or even plots within a single field. Future efforts to manage soil health to improve strawberry production need to consider this underlying variation influencing soil bacterial communities.

Technical Abstract: Bacterial communities play multiple functional roles in soil that have positive and negative feedbacks on plant health. However, relatively few studies have focused on the ecology of soil bacterial communities in commercial strawberry production systems. The objective of this study was to determine if ecological processes influencing soil bacterial communities are consistent among commercial strawberry production locations and plots within the same geographic region. Soil samples were collected using a spatially explicit design from three plots in two commercial strawberry production locations in the Salinas Valley region of California. Soil carbon, nitrogen, and pH were measured for each of the 72 soil samples and bacterial communities were characterized using 16S rRNA sequencing. Multivariate analyses showed bacterial community composition was differentiated between the two strawberry production locations. Analyses of communities within plots demonstrated soil pH and nitrogen were significant predictors of bacterial community composition in one of the three sampled plots. Bacterial communities displayed spatial structure in two plots at one location based on a significant increase in community dissimilarity with increasing spatial distance. Null model analyses identified a lack of phylogenetic turnover among bacterial communities in all plots, but a greater frequency of dispersal limitation in the two plots where spatial structure was also observed. Overall, this work suggests that ecological factors influencing soil bacterial communities are not consistent among different strawberry production locations or plots which may impact the ability to predict or manage the effect of soil microbiomes on strawberry health.