Fig. 6. Evidence for additional phage resistance mechanisms.

a, Recovery of M. abscessus GD01 transposon mutants resistant to phages BPs, phKSW1, Muddy and Muddy_REM1. A culture of an M. abscessus GD01 transposon library (GD01 Tn Lib) containing approximately 10⁶ c.f.u. was plated onto phage-seeded plates as indicated. b, Phage infection profiles of resistant mutants. Tenfold serial dilutions of phages BPsΔ33HTH_HRM10 (‘BPs’), phKSW1, Muddy, Muddy_REM1 and ZoeJΔ43–45 (‘ZoeJ’) (as indicated on the left) were spotted onto lawns of M. abscessus GD01 or mutants isolated as resistant to TPP-independent phages phKSW1 and Muddy_REM1. Mutant designations indicate that they are Tn insertions (Tn), the phage used for mutant selection (that is, phKSW1 or Muddy_REM1) and the mutant number (for example, RM1, RM2 and so on). Where siblings are suspected (Extended Data Table 1), only one representative is shown; suspected siblings showed similar results. c, Organization of a putative candidate PICI in M. abscessus GD01. The satellite region is defined by the attL and attR attachment sites resulting from site-specific integration at a tRNA-Leu gene (GD01 coordinates 1158039 to 1170246). It contains several phage-related genes (green arrows) with the putative functions indicated. At the extreme right-hand end of the PICI, a gene (locus tag EXM25_05825) carries a DUF4145 domain implicated in phage defence in other systems. Four mutants contain a Tn insertion at the site, indicated by the vertical arrow. d, TLC analysis of total lipids extracted from M. abscessus GD01 and transposon mutants isolated as resistant to TPP-independent phages. e, Adsorption of BPsΔ33HTH_HRM10 and phKSW1 to GD01Tn_phKSW1_RM1 (blue, top panels) and to GD01Tn_phKSW1_RM2 (green, bottom panels). Adsorption to GD01 performed in parallel is shown in black. The proportions of phage particles remaining in solution are shown at different times after infection. Assays were performed in duplicate twice and data presented are mean ± s.d.