Bradyrhizobium japonicum의 저온 전처리에 의한 환경스트레스 내성 증진에 대한 연구

초록

Bradyrhizobium japonicum is a soil bacterium with a unique ability to infect the roots of leguminous plants and establish a nitrogen-fixing symbiosis, which has been used as a microbial manure. In this study, we examined the viability of the bacterium after long term storage and the stress response after pre-treatment of cells with cold temperature. This bacterium, although decreased about 10 fold, has been shown to maintatin the viability and ability to nodulate after a long term storage in water. Therefore, preservation of B. japonicum in water suspensions could provide a simple and inexpensive alternative to current method of dried peat or other materials as a carrier. Moreover, when pre-treated with cold temperature(4℃) for 16 hr, B. japonicum increased the viability in subsequent stress-conditions such as alcohol, H2O2, heat and freezing(-20℃)/thawing. For cold adpatation, cultured B. japonicum was exposed to 4℃. Upon subsequent exposure to various conditions, the number of adapted cells pretreated by cold adaptation was 10-1000 fold higher than that of non-adaptated ones.