Fig 6.

Schematic model of host control by endofungal bacteria. The recolonization of apo-symbiotic R. microsporus by the isolated wild-type endosymbiont, M. rhizoxinica, restores the host’s ability to form sporangiospores (left panel). M. rhizoxinica strains lacking a functional T3SS are unable to infect fungal hyphae and, as a consequence, fail to cause sporulation (middle panel). M. rhizoxinica that lack MTALs successfully reinfect the fungal host; however, in the absence of the T3SS-associated MTALs, the sporulating phenotype indicative of a stable symbiosis is profoundly impaired (right panel).