Author(s): T. Al-Ostad, N. Al-Mansour & E. Al-Saleh
The exposure of the environment in Kuwait to crude oil pollution has detrimental
effects on the ecological systems.
The selective pressure created by the addition
of crude oil is expected to impact the bacterial community structures of affected
ecosystems such as the nodule bacteroids by enhancing the growth of crude oildegrading
and/or tolerant microbiota.
In the present study, the effect of crude oil
on the structure of the crude oil-degrading nodule bacteroids community of
Arachis hypogaea is investigated.
Sequence analysis of 16S rDNA amplified
from nodule-bacteroids isolated from Arachis hypogaea grown in crude oil
untreated and treated soils demonstrated the tendency of Gram negative
bacteroids (β-proteobacteria and γ-proteobacteria) to prevail in treated soils.
Crude oil mineralization studies showed that predominant bacteroids have higher
rates of crude oil mineralization (5.5 µg/min) compared to Gram positive
bacteroids (2.1 µg/min).
Furthermore, the effect of crude oil addition on nodules
size, number and distribution was recorded.
Bigger nodules (diameter of
3.13±0.058mm) were detected in untreated soil compared to that of treated soil
(diameter of 1.97±0.122mm).
In addition, the distribution of nodules on
different parts of roots of untreated and treated plants was significantly different
Higher numbers of nodules were detected in the upper parts of the
roots of Arachis hypogaea grown in untreated and treated soils (124±0.455 and
79±1.10 nodules/plant respectively) compared to that observed in the lower parts
of the roots (76±1.13 and 7±0.31 nodules/plant respectively).
number of nodules (200±0.361 nodules/plant) was recorded for plants grown in
untreated soils followed by that of treated soils (86±1.4 nodules/plant).
results are discussed in the context of using Arachis hypogaea to restore
degraded soils and to bioremediate crude oil contamination in Kuwait.
arachis hypogaea, nodule, crude oil, bacteroids, 16S rDNA,
Size: 540 kb
Paper DOI: 10.2495/GEO080141
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