TY - JOUR
T1 - Assessment of plant growth promoting bacterial populations in the rhizosphere of metallophytes from the Kettara mine, Marrakech
AU - Benidire, L.
AU - Pereira, S. I. A.
AU - Castro, P. M. L.
AU - Boularbah, A.
N1 - Funding Information:
The authors acknowledge the financial support of the “Convention de coopération CNRST-Morocco/FCT-Portugal.” This work was also supported by Portuguese Funds through Fundação para a Ciência e a Tecnologia (FCT) under the project UID/Multi/50016/2013. S.I.A. Pereira thanks the grant SFRH/BPD/65134/2009 from FCT (Portugal), Fundo Social Europeu and Fundos Nacionais do MEC through the program QREN-POPH-Tipologia 4.1-Formação Avançada. We also thank Dr. A. Pandey for hosting Dr. A. Boularbah during his stay at the GB Paint Institute of the Himalayan Environment and Development, India, under the CV Raman International Fellowship program for African Researchers 2012, giving him the opportunity to work on PGPRs. The authors are grateful to Dr. A. El Gharmali for his constant help in the analysis of the heavy metals in different samples and Dr. R.C. Pullar for proofreading and correcting the English of this article.
Publisher Copyright:
© 2016, Springer-Verlag Berlin Heidelberg.
PY - 2016/11/1
Y1 - 2016/11/1
N2 - Soil heavy metal contamination resulting from mining activities constitutes a major environmental problem worldwide. The spread of heavy metals is often facilitated by scarce vegetation cover, so there is an urgent need to improve plant survival and establishment in these metalliferous areas. This study is aimed at the isolation and analysis of the phylogenetic relationship of culturable bacteria from the rhizosphere of metallophyte plants growing in the Kettara mine, in Marrakech, in order to select plant growth-promoting rhizobacteria (PGPR), which could be used in assisted-phytoremediation. Bacterial isolates were grouped by random amplified polymorphic DNA analysis and identified by 16S rRNA gene sequencing. Strains were further characterized for the production of plant growth-promoting (PGP) substances, such as NH3, siderophores, indol-3-acetic acid (IAA), hydrogen cyanide, and extracellular enzymes, for ACC-deaminase activity, their capacity to solubilize phosphate, and for their tolerance to heavy metals and acidic pH. Rhizosphere soils were highly contaminated with Cu and Zn and presented low fertility. Phylogenetic analysis showed that the rhizobacteria were affiliated to three major groups: γ-Proteobacteria (48 %), β-Proteobacteria (17 %), and Bacilli (17 %). The most represented genera were Pseudomonas (38 %), Bacillus (10 %), Streptomyces (10 %), and Tetrathiobacter (10 %). Overall, rhizobacterial strains showed an ability to produce multiple, important PGP traits, which may be helpful when applied as plant growth promoter agents in contaminated soils. PGPR were also able to withstand high levels of metals (up to 2615.2 mg Zn l−1, 953.29 mg Cu l−1, and 1124.6 mg Cd l−1) and the order of metal toxicity was Cd > Cu > Zn. The rhizobacterial strains isolated in the present study have the potential to be used as efficient bioinoculants in phytoremediation strategies for the recovery of Kettara mine soils.
AB - Soil heavy metal contamination resulting from mining activities constitutes a major environmental problem worldwide. The spread of heavy metals is often facilitated by scarce vegetation cover, so there is an urgent need to improve plant survival and establishment in these metalliferous areas. This study is aimed at the isolation and analysis of the phylogenetic relationship of culturable bacteria from the rhizosphere of metallophyte plants growing in the Kettara mine, in Marrakech, in order to select plant growth-promoting rhizobacteria (PGPR), which could be used in assisted-phytoremediation. Bacterial isolates were grouped by random amplified polymorphic DNA analysis and identified by 16S rRNA gene sequencing. Strains were further characterized for the production of plant growth-promoting (PGP) substances, such as NH3, siderophores, indol-3-acetic acid (IAA), hydrogen cyanide, and extracellular enzymes, for ACC-deaminase activity, their capacity to solubilize phosphate, and for their tolerance to heavy metals and acidic pH. Rhizosphere soils were highly contaminated with Cu and Zn and presented low fertility. Phylogenetic analysis showed that the rhizobacteria were affiliated to three major groups: γ-Proteobacteria (48 %), β-Proteobacteria (17 %), and Bacilli (17 %). The most represented genera were Pseudomonas (38 %), Bacillus (10 %), Streptomyces (10 %), and Tetrathiobacter (10 %). Overall, rhizobacterial strains showed an ability to produce multiple, important PGP traits, which may be helpful when applied as plant growth promoter agents in contaminated soils. PGPR were also able to withstand high levels of metals (up to 2615.2 mg Zn l−1, 953.29 mg Cu l−1, and 1124.6 mg Cd l−1) and the order of metal toxicity was Cd > Cu > Zn. The rhizobacterial strains isolated in the present study have the potential to be used as efficient bioinoculants in phytoremediation strategies for the recovery of Kettara mine soils.
KW - Bacterial diversity
KW - Heavy metals
KW - Kettara mine
KW - Metal resistance
KW - Plant growth-promoting rhizobacteria
KW - Rhizosphere soils
UR - http://www.scopus.com/inward/record.url?scp=84982128191&partnerID=8YFLogxK
U2 - 10.1007/s11356-016-7378-6
DO - 10.1007/s11356-016-7378-6
M3 - Article
C2 - 27522210
AN - SCOPUS:84982128191
SN - 0944-1344
VL - 23
SP - 21751
EP - 21765
JO - Environmental Science and Pollution Research
JF - Environmental Science and Pollution Research
IS - 21
ER -
