In situ characterization of mercury-resistant growth-promoting fluorescent pseudomonads.
Pseudomonas fluorescens strains PRS9 and GRS1 (wild type) were made mercury resistant PRS9Hg(r) (147 microM HgCl2) and GRS1Hg(r) (55 microM HgCl2), respectively, in King's medium by enrichment selection and their in situ root colonization studies were carried out. Mercury resistant mutant of PRS9 was stable and resulted in significant increase in root and shoot fresh weight (P < 0.05). Both the mutants are positive for indoleacetic acid (IAA), 'P' solubilization and siderophore production. PRS9, potent 'P' solubilizer, exhibited higher 'P' solubilization as compared to GRS1. After 2 weeks of inoculation, the population level of wild type PRS9 and its mercury resistant mutants has increased (50 fold). Mercury resistance has no adverse effect on the growth promoting properties of mutants besides being comparable in its morphological and physiological properties with their wild type counterpart. Furthermore, mercury resistant character facilitates rhizospheric competition and thus helpful for establishment of growth promoting strains where metal ions are either limiting and/or present at toxic level.
Gupta
Abhishek
A
Department of Microbiology, College of Basic Sciences and Humanities, G.B. Pant University of Agriculture and Technology, Pantnagar-263 145, India.
Rai
Vivek
V
Bagdwal
Nidhi
N
Goel
Reeta
R
D018533:Biomass; D024881:Drug Resistance, Bacterial; D007210:Indoleacetic Acids / Q000378:metabolism; D008628:Mercury / Q000494:pharmacology*; D010758:Phosphorus / Q000378:metabolism; D063245:Plant Development; D018517:Plant Roots; D018520:Plant Shoots; D010944:Plants / Q000382:microbiology*; D011549:Pseudomonas / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D017262:Siderophores / Q000096:biosynthesis; D012988:Soil Microbiology
D007210:Indoleacetic Acids; D017262:Siderophores; D010758:Phosphorus; D008628:Mercury