Table 4.

List of bacterial endophytes involved in the phytoremediation of organic pollutants from contaminated soil (the degradation potential of endophytes is also briefly summarized)

Site	Endophytes	Isolated plant parts	Soil contaminants	Degradation capacity	References
Field experiment; car manufacturing factory, Genk, Belgium	Pseudomonas sp., Arthrobacter sp., Enterobacter sp., and Bacillus sp.	Root, stem, and leaf	BTEX	Endophytic bacteria were isolated from the root, stem, and leaf of two cultivars of a poplar tree that grows on a BTEX-contaminated site and has the ability to degrade BTEX compounds	[159]
Campus of Institute of Technology, Carlow, Ireland	Pseudomonas putida VM1450	Stem sap of poplar trees	*2,4-D degradation	Inoculated plants showed a higher capacity for the removal of 2,4-dichlorophenoxyacetic acid from the soil and did not show accumulation of 2,4-dichlorophenoxyacetic acid in their aerial tissues	[75]
Diesel-contaminated site; Seibersdorf; Austria	Pseudomonas sp. strain ITRI53	Roots of Italian ryegrass (Lolium multiflorum var. taurus, Poaceae)	Hydrocarbon degradation	alkB gene could be expressed in the rhizosphere and planta. Inoculation of Pseudomonas sp. ITR153 was superior to the rhizosphere in colonization alkB expression	[17]
Greenhouse experiment; Lower Austria, Austria	Pantoea sp. ITSI10, Pantoea sp. BTRH79, and Pseudomonas sp. MixRI75	Italian ryegrass (Lolium multiflorum var. taurus)	Hydrocarbon (diesel) degradation	Maximum hydrocarbon reduction was reported from vegetated soil; 79% hydrocarbon reduction was achieved with inoculated plants compared to non-inoculated plants. Higher degradation potential was due to the higher microbial densities and metabolic activities of the inoculant strains	[8]
Agricultural farm of Lower Austria, Austria; greenhouse experiment	E. ludwigii strains ISI10-3 and BRI10-9	Italian ryegrass (Lolium multiflorum var. taurus), birdsfoot trefoil (Lotus corniculatus var. leo, Fabaceae), and alfalfa (Medicago sativa var. harpe, Fabaceae)	Hydrocarbon (diesel) degradation and ACC deaminase activities	Plants inoculated with E. ludwigii strains ISI10-3 and BRI10-9, highly degrade 68% of diesel-contaminated soil (spiked with 1% diesel); presence of CYP153 gene in E. ludwigii strains plays an important role in the degradation of pollutants	[262]
In vitro experiment; Daniaopi manmade constructed wetland, Taipei, Taiwan	Achromobacter xylosoxidans F3B	Roots of Phragmites australis (Cav.) Trin. ex Steud. (Poaceae) and Ipomoea aquatica Forssk. (Convolvulaceae)	Catechol and phenol (petroleum) degradation	The hydroponic test revealed 100% catechol removal by F3B inoculated A. thaliana compared to unplanted soil. Soil test indicated 72.7% removal of total petroleum hydrocarbons by F3B endophyte inoculated A. thaliana compared to unplanted soil	[90]
Microcosm experiment; Institute of Technology, Carlow, Ireland	P. putida VM144	Stem tissue of poplar	Naphthalene degradation	Compared to control soil, 40% more naphthalene was removed from the soil (amended with 250 mg/kg naphthalene) in the pea plant inoculated with P. putida VM1441(pNAH7)	[74]
Greenhouse and field trial; agricultural farm of Shanghai Normal University, China	Burkholderia cepacia strain FX2	Zea mays L. and Triticum sp. (Poaceae)	Toluene degradation	The toluene volatilization experiment revealed that FX2 inoculated plants release much less toluene compared to the control	[244]
Field trial experiment; Cd-contaminated site, Belgium	Burkholderia sp. HU001, Pseudomonas sp. HU002	Willow	Production of siderophores, organic acids, and indole-3-acetic acid showed increased resistance to Cd and toluene	Inoculation of both isolates in willow cutting resulted in a 80% decrease in toluene evapotranspiration without affecting the Cd uptake and translocation	[249]
In vitro experiment; Microbiological Engineering of Agricultural Environment, China; Pot Experiment	Enterobacter sp. 12J1	Root and stem of Allium macrostemon Bunge (Amaryllidaceae)	Pyrene degradation, IAA, and siderophore production	In the live bacterial inoculation experiment, an increase in pyrene removal was observed ranging from 60 to 107% in the planted soils treated with 100 mg/kg of pyrene compared to the unplanted soils. The pyrene removal rate increased by 43 to 65% in planted soils inoculated with live bacteria compared to planted soils inoculated with the dead bacteria	[209, 210]
Greenhouse experiment; Hasselt University campus; Belgium	B. cepacia VM1468	Yellow lupine	TCE degradation and Ni resistance	Inoculation with Ni-resistant B. cepacia VM1468 degrading TCE decreased the TCE release and increased the Ni uptake by the roots of the lupine plant exposed to 40 mg/L and 10 mg/L TCE	[248]
Greenhouse experiment; Hasselt University campus; Belgium	P. putida W619-TCE	Populus sp. (Salicaceae)	TCE degradation	Inoculation of P. putida improved TCE degradation in poplar plants exposed to 200 mg/L and 400 mg/L	[251]
In vitro experiment; University of Washington, Seattle, Washington, USA	Enterobacter sp. strain PDN3	Populus sp. (hybrid) (Salicaceae)	TCE degradation	Neither chloride released nor TCE removal was observed in samples without PDN3. However, inoculation with PDN3 reduced TCE levels from 72.4 to 30.1 µM in 24 h with a simultaneous release of 127 µM chloride ion and nearly 80% of TCE (55.3 µM) was dechlorinated by PDN3 in 5 days with the production of 166 µM chloride ion, indicating degradation capacity	[104]