ECOLOGICAL MONITORING OF LACZ MARKED STRAIN OF AZOTOBACTER CHROOCOCCUM IN THE RHIZOPLANE OF TRITICUM AESTIVUM

Abstract

The potential of A. chroococcum as a biofertilizer to improve the crop productivity is well recognized which has accelerated its use as bioinoculants. Unfortunately a huge amount of microbial inoculants are being dumped into the environment without understanding the ecological factors that control their fate and importance. The introduction of marker genes that can be easily identified using a chromogenic substrate offers an opportunity for the survival studies of the inoculants. The establishment of lacZ marked strain of Azotobacter chroococcum Mac 27 in the rhizosphere of Triticum aestivum under pothouse conditions was studied. The lacZ marked strain formed blue colonies on selective media and could be identified from soil on the basis of this character. The transconjugant was able to survive in the rhizosphere of Triticum aestivum under pothouse conditions and maintained a population of about 10⁶ cfu/plant root after 90 days of sowing in plants treated with A.chroococcum Mac 27 L and the strain has been found to be reliable for ecological studies.