# Comparison of Predatory Phenotypes and Genotypes Between Bdellovibrio sp. BIS2 and Bacteriovorax sp. HI3 Isolated From the Same Freshwater Environment

## TL;DR

Two predatory bacteria from the same freshwater environment show different hunting behaviors and genetic traits, which help them coexist.

## Contribution

This study reveals distinct predatory behaviors and genetic differences between two BALO strains from the same environment.

## Key findings

- BIS2 has high motility and incomplete prey lysis, while HI3 shows efficient localized predation and thorough lysis.
- Genetic differences, including flagellar genes in BIS2 and hydrolytic enzymes in HI3, contribute to distinct predatory traits.
- Unique genomic regions suggest genetic divergence drives specialized predatory properties in BALOs.

## Abstract

Bdellovibrio and like organisms (BALOs) are predatory bacteria, which play crucial roles in shaping community structure and maintaining diversity in microbial ecosystems. However, functional and genetic variation among coexisting BALOs remains largely unexplored. Here, we characterised Bdellovibrio sp. BIS2 and Bacteriovorax sp. HI3, which were isolated from the same freshwater environment at different time points. Predation assays and a functional genomic analysis revealed that the predators have distinct prey ranges and predatory behaviours with associated genotypic differences, which may contribute to niche partitioning in the shared habitat. BIS2 possessed an extensive set of flagellar genes, likely contributing to its higher motility and rapid spatial exploration. However, cell debris remained after predation because the prey cells were incompletely lysed. HI3 displayed efficient localised predation and thorough lysis of prey cellular components. The difference in predation efficiency was likely attributed to distinct profiles of hydrolytic enzymes in the two BALOs, including enzymes critical for prey cell lysis and exit from the prey. Genomic regions unique to each predator with predation‐associated genes suggest that genetic divergence drove the evolution of specialised predatory properties across BALOs. These findings provide insights into variation in predatory traits among BALOs, a key mechanism enabling coexistence and adaptation.

Bdellovibrio and like organisms (BALOs) have gained attraction owing to their ecological and practical significance. This study comparatively investigated two BALO strains from the same freshwater pond, Bdellovibrio sp. BIS2 and Bacteriovorax sp. HI3, and revealed significant variation in their predatory behaviours and associated genetic profiles, likely contributing to niche partitioning and enabling BALOs to coexist and adapt in shared habitats.