ASGSB 1998 Annual Meeting Abstracts

[36]
PSEUDOMONAS AERUGINOSA: PERSISTENCE IN THE RHIZOSPHERE.   S.J. Bernick¹, A. Matos², J.L. Garland³. ¹Olympic College, Bremerton, WA, ²Department of Biology, Univ. of South Florida, ³ Dynamac Corporation, Kennedy Space Center.

Advanced Life Support (ALS) systems such as the planned International Space Station will utilize bioregenerative life support systems to facilitate extended duration space missions. Plants will play an integral part of such systems. As a result of their potential role as a source of oxygen, food, and filtration, these plants may also serve as reservoirs for human-associated bacteria (H-AB). Certain opportunistic bacteria, such as Pseudomonas aeruginosa, warrant particular attention. The ability of P. aeruginosa to persist in the rhizosphere of hydroponically grown wheat was examined by enumeration of these organisms after a seven-day incubation period. The factors examined were: (1) the diversity of the rhizosphere community, (2) the density of the invading organism, and (3) the time after planting at which the invasion occurs. Pseudomonas aeruginosa was introduced into wheat plants containing rhizosphere microbial communities of high, medium, and low diversity. Thirty six plants were inoculated with P. aeruginosa, with half of the plants receiving inoculation seven days after planting and half receiving inoculation 21 days after planting. The amount of P. aeruginosa in the inoculum was manipulated to vary the invader density. This research indicates that the time after planting at which invasion occurred does not effect the persistence of the P. aeruginosa. The diversity of the microbial community at the time of invasion also has little effect. However, the density of the P. aeruginosa at the time of invasion plays a significant role in its ability to survive.

This could be an important consideration when engineering biomass production or graywater recycling systems in an ALS environment. (Supported by the NASA Space Life Sciences Training Program)

Back to Meeting Program