title: Enhanced cadmium accumulation and tolerance in transgenic tobacco overexpressing rice metal tolerance protein gene OsMTP1 is promising for phytoremediation.
abstract: One of the most grievous heavy metal pollutants in the environment is cadmium (Cd), which is not only responsible for the crop yield loss owing to its phytotoxicity, but also for the human health hazards as the toxic elements usually accumulate in the consumable parts of crop plants. In the present study, we aimed to isolate and functionally characterize the OsMTP1 gene from indica rice (Oryza sativa L. cv. IR64) to study its potential application for efficient phytoremediation of Cd. The 1257 bp coding DNA sequence (CDS) of OsMTP1 encodes a ∼46 kDa protein belonging to the cation diffusion facilitator (CDF) or metal tolerance/transport protein (MTP) family. The OsMTP1 transcript in rice plant was found to respond during external Cd stress. Heterologous expression of OsMTP1 in tobacco resulted in the reduction of Cd stress-induced phytotoxic effects, including growth inhibition, lipid peroxidation, and cell death. Compared to untransformed control, the transgenic tobacco plants showed enhanced vacuolar thiol content, indicating vacuolar localization of the sequestered Cd. The transgenic tobacco plants exhibited significantly higher biomass growth (2.2-2.8-folds) and hyperaccumulation of Cd (1.96-2.22-folds) compared to untransformed control under Cd exposure. The transgenic plants also showed moderate tolerance and accumulation of arsenic (As) upon exogenous As stress, signifying broad substrate specificity of OsMTP1. Together, findings of our research suggest that the transgenic tobacco plants overexpressing OsMTP1 with its hyperaccumulating activity and increased growth rate could be useful for future phytoremediation applications to clean up the Cd-contaminated soil.
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
authors.forename: Natasha
authors.initials: N
authors.lastname: Das
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
authors.forename: Surajit
authors.initials: S
authors.lastname: Bhattacharya
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India. Electronic address: maitimk@hijli.iitkgp.ernet.in.
authors.forename: Mrinal K
authors.initials: MK
authors.lastname: Maiti
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D060054:Agrobacterium / Q000187:drug effects / Q000378:metabolism; D001151:Arsenic / Q000378:metabolism; D001673:Biodegradation, Environmental / Q000187:drug effects; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D003198:Computer Simulation; D017343:Genes, Plant; D012275:Oryza / Q000187:drug effects / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects; D030821:Plants, Genetically Modified; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological / Q000187:drug effects; D013347:Subcellular Fractions / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D014170:Transformation, Genetic / Q000187:drug effects
chemical_list: D010940:Plant Proteins; D013438:Sulfhydryl Compounds; D002104:Cadmium; D001151:Arsenic
keywords: Cadmium tolerance and accumulation; Genetic engineering; Metal tolerance protein; OsMTP1; Phytoremediation; Transgenic tobacco plant