LuxAB-Labeling of Methylparathion-Degrading Bacterium Pseudomonas sp.DLL-1 and Its Fate in the Soil

The plasmid pTR102 containing LuxAB gene was translated into methylparathion degrading bacterium Pseudomonas sp.DLL-1 by the tri parent conjugation method.The plasmid pTR102 in conjugator DLL-1-B was considerably stable and had no serious effect on the growth and methylparathion degrading capacity of the host.The population of DLL-1-B declined following its introduction into soil,rather slowly in the first two days and rapidly afterwards.When the population fell down to 10 ³～10 ⁴ g ^-1 dry soil,it leveled off.The population of DLL-1-B dropped more rapidly and its life span was much shorter in water than in soil.The mobility of DLL-1-B cells on upland soil was poor, so they usually existed in the upper 10 cm, whereas it was much better in paddy field and 2×10 ² g ^-1 dry soil of DLL-1-B could be detected in soil 20～30 cm in depth.