Fig. 4.

Presence of btl genes in geographically diverse isolates of Mycetohabitans spp. and the effect of substituting btl18-14 for btl19-13. (A) World map showing the location and substrate from which the R. microsporus hosts of the Mycetohabitans spp. assessed were isolated, generated using rworldmap (39). More information on the strains is available in SI Appendix, Table S3. (B) Southern blots of genomic DNA from each strain, digested with AatII and probed with btl19-13 amplified from B13. Strains are identified by the culture collection accession number of their fungal hosts. ATCC 52813 represents B13, ATCC 52814 B14, and ATCC 62417 B1. The arrow points to a faint high-molecular-weight band in an otherwise empty lane, which can be more clearly seen in SI Appendix, Fig. S5. (C and D) Growth of R. microsporus infected with wild-type B13 (WT), B13∆btl19-13 (mutant), the mutant strain with pBtl19-13, or the mutant strain with pBtl18-14, on half-strength potato dextrose agar without (C) or with (D) 0.005% SDS after 3 or 6 d, respectively, at 28 °C. Data shown represent values from 10 replicate plates each and were analyzed by ANOVA with a post hoc Tukey’s test. The experiment was repeated twice and yielded the same result. In each plot, different lowercase letters above any two groups indicate a significant difference between the means (P < 0.001).