Hydrocarbon degradation potential and plant growth-promoting activity of culturable endophytic bacteria of Lotus corniculatus and Oenothera biennis from a long-term polluted site

Abstract

Many endophytic bacteria exert beneficial effects on their host, but still little is known about the bacteria associated with plants growing in areas heavily polluted by hydrocarbons. The aim of the study was characterization of culturable hydrocarbon-degrading endophytic bacteria associated with Lotus corniculatus L. and Oenothera biennis L. collected in long-term petroleum hydrocarbon-polluted site using culture-dependent and molecular approaches. A total of 26 hydrocarbon-degrading endophytes from these plants were isolated. Phylogenetic analyses classified the isolates into the phyla Proteobacteria and Actinobacteria. The majority of strains belonged to the genera Rhizobium, Pseudomonas, Stenotrophomonas, and Rhodococcus. More than 90% of the isolates could grow on medium with diesel oil, approximately 20% could use n-hexadecane as a sole carbon and energy source. PCR analysis revealed that 40% of the isolates possessed the P450 gene encoding for cytochrome P450-type alkane hydroxylase (CYP153). In in vitro tests, all endophytic strains demonstrated a wide range of plant growth-promoting traits such as production of indole-3-acetic acid, hydrogen cyanide, siderophores, and phosphate solubilization. More than 40% of the bacteria carried the gene encoding for the 1-aminocyclopropane-1-carboxylic acid deaminase (acdS). Our study shows that the diversity of endophytic bacterial communities in tested plants was different. The results revealed also that the investigated plants were colonized by endophytic bacteria possessing plant growth-promoting features and a clear potential to degrade hydrocarbons. The properties of isolated endophytes indicate that they have the high potential to improve phytoremediation of petroleum hydrocarbon-polluted soils.

Cyperus laevigatus L. Enhances Diesel Oil Remediation in Synergism with Bacterial Inoculation in Floating Treatment Wetlands

“…Due to absorption of easily degradable hydrocarbons in the plant roots, the superior hydrocarbons removal was observed during the initial 30 days of the experiment in T2 treatment. These results are in agreement with the finding of previous research [39,40]. The literature study revealed that in spite of microorganisms, the degradation of hydrocarbons is also assisted by plants that play a fundamental role by taking up the hydrocarbons in their roots and shoots and change them into less harmful substances [41,42].…”

Biosurfactant production and hydrocarbon degradation activity of endophytic bacteria isolated from Chelidonium majus L.

“…Pawlik et al examined the potential for hydrocarbons degradation (diesel oil, n -hexane and p -xylene degradation) of endophytic bacteria isolated from Lotus corniculatus and Oenothera biennis growing in contaminated soil [ 47 ]. Isolated endophytes belonged mainly to the genera of Pseudomonas, Stenotrophomonas, Rhizobium, and Rhodococcus .…”

“…Isolated endophytes belonged mainly to the genera of Pseudomonas, Stenotrophomonas, Rhizobium, and Rhodococcus . Over 90% of them were able to utilize diesel oil as a carbon source [ 47 ]. Also, Philips et al studied the degradation abilities of endophytes isolated from the prairie plants.…”

Rhizoremediation of petroleum hydrocarbons: a model system for plant microbiome manipulation

“…Similarly, the presence of ryegrass was shown to stimulate the expression of bacterial PAH-ring hydroxylating dioxygenase genes, such as nidA3, pdoA, nahAc and phnAc (Guo et al, 2017a,b). Several Lotus corniculatus (common bird's-foot trefoil) and Oenothera biennis (common evening primrose) root endophytes belonging to the genera Rhizobium, Pseudomonas, Stenotrophomonas and Rhodococcus harbored genes encoding for CYP153 alkane hydroxylases and showed the capacity to grow with n-hexadecane as sole source of carbon (Pawlik et al, 2017). Other plants, such as Achillea millefolium (yarrow), Soligado canadensis (Canadian goldenrod), Trifolium aureum (hop clover) and Dactylis glomerata (orchard grass), growing in a heavily contaminated site, harbored hydrocarbon-degrading bacterial endophytes mostly belonging to the Actinobacteria (Lumactud et al, 2016).…”