A phylogenetic host-range index reveals ecological constraints in phage specialisation and virulence

Phages are typically known for having a limited host range, targeting particular strains within a bacterial species, but accurately measuring their specificity remains challenging. Factors like the genetic diversity or epidemiology of host bacteria are often disregarded, despite their potential influence on phage specialisation and virulence. This study focuses on the Ralstonia solanacearum species complex (RSSC), which comprises genetically diverse bacteria responsible for a major plant disease. It uses a diversified collection of RSSC phages to develop new host-range analysis methods and to test ecological and evolutionary hypotheses on phage host range. We introduce a new \"phylogenetic host-range index\" that employs an ecological diversity index to account for the genetic diversity of bacterial hosts, allowing systematic classification of phages along a continuum between specialists and generalists. We propose and provide evidence that the CRISPR-Cas immune system of bacteria more fr..., , # A phylogenetic host-range index reveals ecological constraints in phage specialisation and virulence

Dataset DOI: [10.5061/dryad.tmpg4f596](10.5061/dryad.tmpg4f596)

## Description of the data and file structure

Here, we aim to assess phage host range by integrating available phylogenetic data with phenotypic data and applying quantitative network analyses of phage-bacteria interactions.

In all the scripts included, this version of R was used: Posit Team (2024). RStudio: IDE for R (Version 2024.04 “Chocolate Cosmos”). Posit Software, PBC. [https://posit.co/](https://posit.co/)

### Files and variables

#### File: TreeRalstoReu

**Description:** The phylogenetic distance between bacterial hosts was calculated by using the phylogenetic tree of the RSSC endoglucanase (*egl*) gene, as previously established to study RSSC diversity (Fegan & Prior, 2005).

#### File: TreeRalstoMauri

**Description:** The phylogenetic distance between bacterial hosts was calculated by using the phylogenet...,