Putative P1B-type ATPase from the bacterium Achromobacter xylosoxidans A8 alters Pb2+/Zn2+/Cd2+-resistance and accumulation in Saccharomyces cerevisiae

AbstractPbtA, a putative P1B-type ATPase from the Gram-negative soil bacterium Achromobacter xylosoxidans A8 responsible for Pb2+/Zn2+/Cd2+-resistance in Escherichia coli, was heterologously expressed in Saccharomyces cerevisiae. When present in Zn2+- and Pb2+/Cd2+-hypersensitive S. cerevisiae strains CM137 and DTY168, respectively, PbtA was able to restore Zn2+- and Pb2+-resistant phenotype. At the same time, the increase of Pb, Zn, and Cd accumulation in yeast was observed. However, Cd2+-tolerance of the pbtA-bearing yeasts dramatically decreased. The PbtA-eGFP fusion protein was localized primarily in the tonoplast and also in the plasma membrane and the perinuclear region corresponding to the endoplasmic reticulum at later growth stages. This indicates that PbtA protein is successfully incorporated into membranes in yeasts. Since PbtA caused a substantial increase of Pb2+/Zn2+-resistance and accumulation in baker's yeast, we propose its further use for the genetic modification of suitable plant species in order to obtain an effective tool for the phytoremediation of sites polluted by toxic transition metals

Phytoextraction of Heavy Metals: A Promising Tool for Clean-Up of Polluted Environment?

Pollution by heavy metals (HM) represents a serious threat for both the environment and human health. Due to their elemental character, HM cannot be chemically degraded, and their detoxification in the environment mostly resides either in stabilization in situ or in their removal from the matrix, e.g., soil. For this purpose, phytoremediation, i.e., the application of plants for the restoration of a polluted environment, has been proposed as a promising green alternative to traditional physical and chemical methods. Among the phytoremediation techniques, phytoextraction refers to the removal of HM from the matrix through their uptake by a plant. It possesses considerable advantages over traditional techniques, especially due to its cost effectiveness, potential treatment of multiple HM simultaneously, no need for the excavation of contaminated soil, good acceptance by the public, the possibility of follow-up processing of the biomass produced, etc. In this review, we focused on three basic HM phytoextraction strategies that differ in the type of plant species being employed: natural hyperaccumulators, fast-growing plant species with high-biomass production and, potentially, plants genetically engineered toward a phenotype that favors efficient HM uptake and boosted HM tolerance. Considerable knowledge on the applicability of plants for HM phytoextraction has been gathered to date from both lab-scale studies performed under controlled model conditions and field trials using real environmental conditions. Based on this knowledge, many specific applications of plants for the remediation of HM-polluted soils have been proposed. Such studies often also include suggestions for the further processing of HM-contaminated biomass, therefore providing an added economical value. Based on the examples presented here, we recommend that intensive research be performed on the selection of appropriate plant taxa for various sets of conditions, environmental risk assessment, the fate of HM-enriched biomass, economical aspects of the process, etc

Analysis of the biodegradative and adaptive potential of the novel polychlorinated biphenyl degrader Rhodococcus sp. WAY2 revealed by its complete genome sequence

The complete genome sequence of Rhodococcus sp. WAY2 (WAY2) consists of a circular chromosome, three linear replicons and a small circular plasmid. The linear replicons contain typical actinobacterial invertron-type telomeres with the central CGTXCGC motif. Comparative phylogenetic analysis of the 16S rRNA gene along with phylogenomic analysis based on the genome-togenome blast distance phylogeny (GBDP) algorithm and digital DNA–DNA hybridization (dDDH) with other Rhodococcus type strains resulted in a clear differentiation of WAY2, which is likely a new species. The genome of WAY2 contains five distinct clusters of bph, etb and nah genes, putatively involved in the degradation of several aromatic compounds. These clusters are distributed throughout the linear plasmids. The high sequence homology of the ring-hydroxylating subunits of these systems with other known enzymes has allowed us to model the range of aromatic substrates they could degrade. Further functional characterization revealed that WAY2 was able to grow with biphenyl, naphthalene and xylene as sole carbon and energy sources, and could oxidize multiple aromatic compounds, including ethylbenzene, phenanthrene, dibenzofuran and toluene. In addition, WAY2 was able to co-metabolize 23 polychlorinated biphenyl congeners, consistent with the five different ring-hydroxylating systems encoded by its genome. WAY2 could also use n-alkanes of various chain-lengths as a sole carbon source, probably due to the presence of alkB and ladA gene copies, which are only found in its chromosome. These results show that WAY2 has a potential to be used for the biodegradation of multiple organic compoundsThis research was funded by GREENER-H2020 (EU), grant number 826312, and MICINN/FEDER EU, grant number RTI2018-0933991- B-I00. D.G.-S. was supported by a MECD FPU fellowship program, grant number FPU14/03965. P.S.-L. was supported by the MICINN FPU fellowship program, grant number FPU18/02169. E.B.-R. was supported by the MECD FPU fellowship program, grant number FPU16/05513. J.S., T.C. and O.U. acknowledge Czech Science Foundation grant number 17–00227S, which enabled PCB co-metabolism experiments to be undertake

Transgenic plants and hairy roots: exploiting the potential of plant species to remediate contaminants

Phytoremediation has emerged as an attractive methodology to deal with environmental pollution, which is a serious worldwide problem. Although important advances have been made in this research field, there are still some drawbacks to become a widely used practice, such as the limited plant's metabolic rate and their difficulty to break down several organic compounds or to tolerate/accumulate heavy metals. However, biotechnology has opened new gateways in phytoremediation research by offering the opportunity for direct gene transfer to enhance plant capabilities for environmental cleanup. In this context, hairy roots (HRs) have emerged as an interesting model system to explore the potential of plants to remove inorganic and organic pollutants. Besides, their use in rhizoremediation studies has also been explored. In this minireview we will discuss the most recent advances using genetic engineering for enhancing phytoremediation capabilities of plants and HRs.Fil: Ibañez, Sabrina Guadalupe. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; ArgentinaFil: Talano, Melina Andrea. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; ArgentinaFil: Ontañon, Ornella Mailén. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; ArgentinaFil: Suman, Jachym. University of Chemistry and Technology; República ChecaFil: Medina, Maria Ines. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; ArgentinaFil: Macek, Tomas. University of Chemistry and Technology; República ChecaFil: Agostini, Elizabeth. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentin

Additional file 1: Table S1. of Complete genome sequence of Pseudomonas alcaliphila JAB1 (=DSM 26533), a versatile degrader of organic pollutants

Description of five regions harboring genes for aromatic compound degradation pathways were identified in the JAB1 genome. (DOCX 34 kb