Metagenomic analysis of rhizosphere microflora of oil-contaminated soil planted with barley and alfalfa

• Published in: PloS one Vol. 13; no. 8; p. e0202127
• Main Authors: Kumar, Vinod, AlMomin, Sabah, Al-Aqeel, Hamed, Al-Salameen, Fadila, Nair, Sindhu, Shajan, Anisha
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 09.08.2018; Public Library of Science (PLoS)
• Subjects: Alfalfa; Bacteria; Barley; Biodegradation; Biodegradation, Environmental; Bioinformatics; Biology and Life Sciences; Bioremediation; Biotechnology; Cluster Analysis; Clustering; Contaminated land; Degradation; Diversity indices; Ecology and Environmental Sciences; Enrichment; Environmental aspects; Flora; Flowers & plants; Genes; Genetic aspects; High-Throughput Nucleotide Sequencing; Hordeum - physiology; Hydrocarbon-degrading bacteria; Hydrocarbons; Hydrocarbons - analysis; Hydrogen-Ion Concentration; Influence; Life sciences; Medicago sativa - physiology; Metagenome; Microbial activity; Microflora; Microorganisms; Next-generation sequencing; Oil; Oil pollution; Petroleum Pollution; Phylogeny; Physical Sciences; Physiological aspects; Phytoremediation; Plant diversity; Plant growth; Prokaryotes; Research and Analysis Methods; Rhizosphere; RNA, Ribosomal, 16S - genetics; rRNA 16S; Sandy soils; Sediment pollution; Seeds; Soil - chemistry; Soil analysis; Soil contamination; Soil Microbiology; Soil microorganisms; Soil Pollutants - analysis; Soil pollution; Studies; Wetlands; Kuwait
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0202127

The role of rhizosphere microbial communities in the degradation of hydrocarbons remains poorly understood and is a field of active study. We used high throughput sequencing to explore the rhizosphere microbial diversity in the alfalfa and barley planted oil contaminated soil samples. The analysis of 16s rRNA sequences showed Proteobacteria to be the most enriched (45.9%) followed by Bacteriodetes (21.4%) and Actinobacteria (10.4%) phyla. The results also indicated differences in the microbial diversity among the oil contaminated planted soil samples. The oil contaminated planted soil samples showed a higher richness in the microbial flora when compared to that of untreated samples, as indicated by the Chao1 indices. However, the trend was different for the diversity measure, where oil contaminated barley planted soil samples showed slightly lower diversity indices. While the clustering of soil samples grouped the oil contaminated samples within and across the plant types, the clean sandy soil samples formed a separate group. The oil contaminated rhizosphere soil showed an enrichment of known oil-degrading genera, such as Alcanivorax and Aequorivita, later being specifically enriched in the contaminated soil samples planted with barley. Overall, we found a few well known oil-degrading bacterial groups to be enriched in the oil contaminated planted soil samples compared to the untreated samples. Further, phyla such as Thermi and Gemmatimonadetes showed an enrichment in the oil contaminated soil samples, indicating their potential role in hydrocarbon degradation. The findings of the current study will be useful in understanding the rhizosphere microflora responsible for oil degradation and thus can help in designing appropriate phytoremediation strategies for oil contaminated lands.