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Plasmids profiles,
antibiotic and heavy metal resistance incidence of
endophytic bacteria isolated from grapevine (Vitis
vinifera L.)
Abdulla D. Altalhi
Biological science department, Faculty of Science,
Taif University, Taif, Saudia Arabia.
E-mail:
aaltalhi2001@hotmail.com.
Accepted 2 October, 2009 |
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Little is
known about the bacterial communities associated with the
plant inhabiting desert ecosystem. In this study, the
bacterial population associated with grapevine (Vitis
vinifera L.) plant, growing desert soil was
analyzed using the culture dependent approach. A total of
111 bacterial isolates were isolated from stems and leaves
samples, collected from different locations and subjected to
further analyses. Based on the identification methods, the
bacterial isolates were grouped into 14 genera. The main
genera are Acetobacter, Acinetobacter,
Citrobacter, Enterobacter, Erwinia,
Escherichia, Methylococcus, Xanthomonas,
Vibrio, Bacillus, Micrococcus,
Planococcus, Staphylococcus and Streptomyces.
Significant differences in the endophytic communities
were observed between plants collected from different sites
and also between plant stems and leaves. All the isolates
were examined for plasmid DNA content and resistance to
antibiotics (Ampicillin, Kanamycin, Tetracyclin) and heavy
metals. Minimum inhibitory concentrations (MICs) of Cu, Cd,
Hg, Mn, Ni and Zn for isolates were also determined.
Resistance was most frequent to Ampicillin (57%), followed
by Kanamycin (53%) and Tetracycline (26%). The highest MICs
observed were 10 µg/ml for mercury, 50 µg/ml for Cu and Cd
and 200 µg/ml for other metals. On a percentage basis,
18.48% of total strains from leaves were found to harbour
plasmids, whereas, 11.83% of the roots isolates contained
plasmids.
Key
words:
Endophytic bacteria, antibiotic resistance, heavy metals,
plasmids. |
