Strain-level heterogeneity in Vibrio parahaemolyticus limits the predictive value of baseline planktonic gene expression for surface-associated phenotypes.

Vibrio (V.) parahaemolyticus is a ubiquitous marine bacterium that persists in dynamic marine environments through adaptive behaviors including motility and biofilm formation. Gene expression data obtained under planktonic conditions are widely used to infer surface-associated phenotypes, implicitly assuming that such measurements are informative of these behaviors. However, the extent to which this assumption holds across genetically diverse strains remains unclear. This study systematically assessed whether baseline transcriptional profiles provide predictive value for surface-associated phenotypes across a diverse panel of V. parahaemolyticus strains. Phenotypic traits and gene expression patterns varied substantially across individual strains. Correlation analyses revealed no robust associations between transcriptional levels and phenotypes after multiple-testing correction, and predictive modeling further demonstrated that transcriptional profiles do not reliably predict surface-associated phenotypes across strains (leave-one-out cross-validation R