Survival dynamics of Bacillus subtilis in water by green fluorescent protein labeling

A cocktail formulation (Bacillus subtilis-dimethomorph, DMBS) was developed with good control of Phytophthora blight of pepper and other crops based on the integrating of biological and chemical control, which was composed of Bacillus subtilis ( BS) and dimethomorph. Based on the general principles of the hydrolysis research of agro-chemicals, the survival kinetics of BS in DMBS in de-ionized water, ground water, tap water, river water, and rain water were studied by using green fluorescent protein ( GFP) labeling and bacteriological methods. The results showed that GFP was an efficient method for detecting the survival of Bacillus subtilis in the five kinds of water environment. At 25 degrees C +/- 1 degrees C, the quantity of the bacteria in its single formulation (SF) and in DMBS was decreased rapidly within 12 d of their storage. After 12 d, the amount of the bacteria exhibited fluctuant ascend or descend with the extending of their storage. At 50 degrees C +/- 1 degrees C, the quantity of bacteria in both formulations was declined quickly during 12 d within incubation in autoclaved and unautoclaved treatments. After that, the amount of the bacteria tend to stabilize or descend mildly. The bacteria was decreased slowly in the five kinds of waters and kept above 10(4) cfu/mL after incubated 86 d under both conditions of (25 +/- 1)degrees C and (50 +/- 1)degrees C. The incubation temperature and autoclaved state had certain effects to the survival dynamic of B. subtilis in SF and in DMBS, while dimethomorph in DMBS had no remarkable effect.