Effects of soil invertebrates on the survival of some genetically engineered bacteria in leaf litter and soil

• Published in: Biology and fertility of soils Vol. 23; no. 3; pp. 221 - 228
• Main Authors: Byzov, B.A, Claus, H, Tretyakova, E.B, Zvyagintsev, D.G, Filip, Z
• Format: Journal Article
• Language: English
• Published: 1996
• Subjects: Aporrectodea caliginosa; Armadillidium vulgare; Azospirillum brasilense; Diplopoda; feeding habits; forest litter; genetic recombination; leaves; microhabitats; mortality; pachyiulus flavipes; plasmids; podzolic soils; Pseudomonas; Pseudomonas putida; Pseudomonas stutzeri; recombinant versus natural plasmids; soil bacteria; soil invertebrates; strain differences; strains
• ISSN: 0178-2762; 1432-0789
• DOI: 10.1007/BF00335948

Seven bacterial strains, most of them bearing natural or recombinant plasmids, were introduced in oak leaf litter or soddy-podzolic soil. In these substrata, which contained litter-dwelling diplopods and isopods, or endogenic earthworms, bacteria survival was followed. In the absence of the animals, the numbers of introduced strains gradually decreased. In the presence of the animals, plasmid-bearing strains of Pseudomonas putida survived at 10(5)-10(7) CFUs g-1 up to 1.5 months in both leaves and soil. The total numbers of bacteria found in excrements from the soil macrofauna were 5-15 times higher than in the food. The numbers of P. putida in the excrements were equal to or higher than in the food. The numbers of Pseudomonas stutzeri JM302 (pLV1013) and Azospirillum brasilense ATCC29710 (pFACII) in the excrements were always 2-10 times lower than in the food. The digestive fluid taken from the middle part of the gut of the diplopod Pachyiulus flavipes showed a strong antibacterial activity. Those bacteria with lower survival in the gut appeared to be more sensitive to digestion by the midgut fluid. In contrast, the hindgut fluid did not suppress the viability of P. stutzeri JM302 (pLV1013). We postulate that the introduced bacteria partially survive the midgut passage and then multiply with a high growth rate in the hindgut of the animals. The environmental consequences of the interactions between soil invertebrates and the released bacteria are discussed.