Fig. 2. Light microphotographs showing different developmental stages ofPasteuria penetrans parasitizing Meloidogyne arenaria race 2 cultured on tomato plants in a hydroponics system. The developmental stages of the bacterium were: A) Germination stage: endospores attached to the cuticle and germ tube (gt) penetrating the cuticle and hypodermis of a second-stage juvenile; BC) vegetative growth stage; includes clusters of mycelia colonies (mc), and thalli (th) disseminated throughout the pseudocoel; D) differentiation stages: thalli fragmentation and detection of quintets, triplets, and doublets; E, F) sporulation stage; developing endospore with distal swollen ends (ds) and appearance of the endospore cortex (c), endospores connected by intercalary strands (arrow); G) mature stage; free mature ellipsoidal endospore with the sporangial wall (ex). Bars = 20 micrometer.