title: Isolation and engineering of plant growth promoting rhizobacteria Pseudomonas aeruginosa for enhanced cadmium bioremediation.
abstract: Although many bacteria are tolerant to heavy metals and play important roles in the immobilization of heavy metals, they cannot always be dependably reproduced under field conditions. In this work, a cadmium (Cd)-resistant bacterium was isolated from a Cd-contaminated oil field and identified as Pseudomonas aeruginosa (Pse-w). We then determined various plant growth promoting features such as the solubilization of phosphate, and the production of indole-3-acetic acid and siderophores. Lastly, we engineered the strain Pse-w-MT by targeting metallothioneins to the cell surface of Pse-w to immobilize Cd2+and promote plant growth. Our data revealed that Pse-w exhibited high levels of resistance to Cd2+(4 mM) and showed various plant growth promoting features. The engineered strain Pse-w-MT was found to adsorb Cd2+mainly via extracellular deposition, and had an enhanced ability for immobilizing Cd2+ions from the external media. Furthermore, the inoculation of Cd-polluted soil with Pse-w-MT significantly elevated the shoot and root biomass and leaf chlorophyll content. Similarly, plants inoculated with Pse-w-MT demonstrated markedly lower Cd2+accumulation in the root and shoot system. It was concluded that plant growth promoting rhizobacteria with a high Cd2+tolerance was an ideal candidate to be engineered for bioremediation and plant growth promotion against Cd-induced stress.
authors.affiliation: Institute of Genomic Medicine, College of Pharmacy, Jinan University.
authors.forename: Junli
authors.initials: J
authors.lastname: Huang
authors.forename: Zhaobing
authors.initials: Z
authors.lastname: Liu
authors.forename: Shiyu
authors.initials: S
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Xu
authors.forename: Yahui
authors.initials: Y
authors.lastname: Gong
authors.forename: Yan
authors.initials: Y
authors.lastname: Yang
authors.forename: Hanxiao
authors.initials: H
authors.lastname: Sun
mesh_terms: D059827:Agricultural Inoculants / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D001673:Biodegradation, Environmental; D018533:Biomass; D002104:Cadmium / Q000378:metabolism* / Q000494:pharmacology; D005818:Genetic Engineering; D007210:Indoleacetic Acids / Q000378:metabolism; D008668:Metallothionein / Q000235:genetics; D063245:Plant Development; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000382:microbiology; D010944:Plants / Q000378:metabolism / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D012231:Rhizobium / Q000302:isolation & purification / Q000378:metabolism; D017262:Siderophores / Q000096:biosynthesis; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D007210:Indoleacetic Acids; D017262:Siderophores; D012989:Soil Pollutants; D002104:Cadmium; C030737:indoleacetic acid; D008668:Metallothionein