/To assert how the phylogeny of Actinobacteria impacts the anti-phage arsenal they encode at a lower taxonomic level, we first examined the mean number of defense systems encoded in a genome depending on the genus. We observed important variations in the number of defense systems encoded between individuals of the same genus, while no major differences could be established between genera of Actinobacteria. When looking this time at the frequency of different systems depending on the actinobacterial genera, we noticed important disparities. For instance, PD-T4-3 and Eleos are extremely enriched in the Rhodococcus genus, while CRISPR-Cas systems are completely absent from the genomes of Brevibacterium and Arthrobacter of the RefSeq database (respectively 25 and 45 genomes).