Genetic labelling and application of the isoproturon-mineralizing Sphingomonas sp. strain SRS2 in soil and rhizosphere.
OBJECTIVE
To construct a luxAB-labelled Sphingomonas sp. strain SRS2 maintaining the ability to mineralize the herbicide isoproturon and usable for monitoring the survival and distribution of strain SRS2 on plant roots in laboratory systems.


RESULTS
We inserted the mini-Tn5-luxAB marker into strain SRS2 using conjugational mating. In the transconjugant mutants luciferase was produced in varying levels. The mutants showed significant differences in their ability to degrade isoproturon. One luxAB-labelled mutant maintained the ability to mineralize isoproturon and was therefore selected for monitoring colonization of barley roots.


CONCLUSIONS
We successfully constructed a genetically labelled isoproturon-mineralizing-strain SRS2 and demonstrated its ability to survive in soil and its colonization of rhizosphere.


CONCLUSIONS
The construction of a luxAB-labelled strain SRS2 maintaining the degradative ability, provides a powerful tool for ecological studies serving as the basis for evaluating SRS2 as a bioremediation agent.
Kristensen
K E
KE
Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Copenhagen K, Denmark.
Jacobsen
C S
CS
Hansen
L H
LH
Aamand
J
J
Morgan
J A W
JA
Sternberg
C
C
Sørensen
S R
SR
D001673:Biodegradation, Environmental; D005818:Genetic Engineering; D006540:Herbicides / Q000378:metabolism*; D001467:Hordeum / Q000382:microbiology; D049453:Luciferases, Bacterial / Q000032:analysis / Q000235:genetics; D008163:Luminescent Measurements; D010671:Phenylurea Compounds / Q000378:metabolism*; D018517:Plant Roots / Q000382:microbiology; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D020578:Sphingomonas / Q000235:genetics / Q000378:metabolism*
D006540:Herbicides; D010671:Phenylurea Compounds; D012987:Soil; D012989:Soil Pollutants; C028904:isoproturon; D049453:Luciferases, Bacterial