Title of article :
Fluorescent pseudomonads occuring in Macrotermes subhyalinus
mound structures decrease Cd toxicity and improve
its accumulation in sorghum plants
Author/Authors :
R. Duponnois، نويسنده , , ?، نويسنده , , M. Kisa a، نويسنده , , K. Assigbetse b، نويسنده , , Y. Prin، نويسنده , , J. Thioulouse، نويسنده , ,
M. Issartel a، نويسنده , , P. Moulin d، نويسنده , , M. Lepage e، نويسنده , , f، نويسنده ,
Issue Information :
هفته نامه با شماره پیاپی سال 2006
Abstract :
Cd-tolerant bacterial strains of fluorescent pseudomonads, mostly belonging to Pseudomonas monteillii, were isolated from termite
mound soil (Macrotermes subhyalinus, a litter-forager and fungus-growing termite), in a Sudanese shrubby savanna, Burkina Faso. Such
large mounds appeared as sites of great bacterial diversity and could be considered as hot spots of metal-tolerant fluorescent
pseudomonads. Microbial isolates were inoculated to Sorghum plants (S. bicolor) in glasshouse experiments with soil amended with
CdCl2 (560 mg Cd kg−1 soil).Microbial functional diversity was assessed at the end of the experiment by measurement of in situ patterns
of catabolic potentials. All the bacteria isolates significantly improved the shoot and total biomass of sorghum plants compared to the
control. Results concerning root biomass were not significant with some strains. Arbuscular mycorrhiza (AM) was greatly reduced by
CdCl2 amendment, and fluorescent pseudomonad inoculation significantly increased AM colonisation in the contaminated soil. The
bacterial inoculation significantly improved Cd uptake by sorghum plants.Measurement of catabolic potentials on 16 substrates showed
that the microbial communities were different according to the soil amendment. Soils samples inoculated with pseudomonad strains
presented a higher use of ketoglutaric and hydroxybutiric acids, as opposed to fumaric acid in soil samples not inoculated. It is suggested
that fluorescent pseudomonads could act indirectly in such metabolic processes by involving a lower rate of degradation of citric acid, in
line with the effect of small organic acid on phytoextraction of heavy metals from soil. This is a first contribution to bioremediation of
metal-contaminated sites with soil-to-plant transfer, using termite built structures. Further data are required on the efficiency of the
bacterial strains isolated and on the processes involved
Keywords :
arbuscular mycorrhizal fungi , fluorescent pseudomonads , Heavy metals , Termite , Phyremediation
Journal title :
Science of the Total Environment
Journal title :
Science of the Total Environment