An endospore suspension of B. amyloliquefaciens Fad82was prepared
as described earlier (Margosch et al., 2006). Briefly, B. amyloliquefaciens
Fad82 was grown overnight in ST1 broth (Difco, Becton, Dickinson and
Company, Sparks, NV, USA) under aerobic conditions. Aliquots of 100 μL
of the overnight culture were plated onto ST1 agar and supplemented
with MnSO4 (10 mg L−1). Plates were incubated at 37 °C for 14 d.
Formation of endospores by B. amyloliquefaciens was confirmed by
phase-contrast microscopy. The surface of the agar was washed with a
sterile saline solution (0.9%). The obtained solution was centrifuged
(2700 ×g for 20 min), and the precipitate was re-suspended in 3 mL
of saline solution. Centrifugation and re-suspension was repeated five
times. Then, the spore suspension was diluted with the saline solution
to an optical density of 2.0 at 600 nm (OD600). This cell density corresponds
to approximately 109 endospores mL−1 (Hofstetter, 2012).
The endospore suspension was stored at 4 °C until inoculation