Yw. Hong et al., OVERCOMING THE METABOLIC LOAD ASSOCIATED WITH THE PRESENCE OF PLASMIDDNA IN THE PLANT-GROWTH PROMOTING RHIZOBACTERIUM PSEUDOMONAS-PUTIDA GR12-2, Canadian journal of microbiology, 41(7), 1995, pp. 624-628
When the broad host range plasmid vector pGSS15 was used to geneticall
y transform the plant growth promoting rhizobacterium Pseudomonas puti
da GR12-2, the transformants were physiologically debilitated. It was
postulated that the expression of the beta-lactamase gene of pGSS15 ca
used a metabolic load resulting in the impaired functioning of the bac
terium. To test this hypothesis, derivatives of pGSS15 that either lac
k the beta-lactamase gene (pYH12-2) or in which a beta-glucosidase gen
e was substituted for the beta-lactamase gene (pYH124) were constructe
d and examined to see whether their presence also impaired the functio
ning of P. putida GR12-2. On the basis of growth rates, siderophore pr
oduction, and the ability to stimulate canola root elongation in steri
le growth pouches, neither of the newly constructed plasmids debilitat
ed P. putida GR12-2. In addition, P. putida GR12-2 transformed with pY
H124 facilitated the proliferation of the bacterium in minimal medium
containing cellobiose at low temperature. This latter trait may enable
P. puticia GR12-2 to persist in the soil in competition with other mi
croorganisms.