title: Regulations of essential amino acids and proteomics of bacterial endophytes Sphingomonas sp. Lk11 during cadmium uptake.
abstract: Endophytic bacteria have been recently known for their potential to bioaccumulate metal from contaminated mediums. However, little is known about the physiological responses of phytohormone producing (gibberellins and auxins) endophytes during metal stressed environment. Endophytic bacteria Sphingomonas sp. LK11 was assessed for metals bioaccumulation and its physiological responses towards metal stress. The endophyte was grown in cadmium (Cd), zinc (Zn), aluminum (Al), manganese (Mn), and copper (Cu) contaminated mediums. The results revealed significantly higher endophytic growth potentials in Cd, Cu and Zn contaminations; however, the bio-accumulation rate of Cd was more prolific as compared to Zn and Cu. Interestingly, the SDS-PAGE profile showed increased expressions of proteins in Zn and Cu than in Cd. A similar attenuate response of amino acids was also observed for Cd than in case of Zn and Cu. Only asparagine, glutamate and proline showed significant impact in Cd while Cu and Zn had significantly higher responses of almost all amino acids. Detailed protein profile showed the activation of chaperone, antioxidative and detoxification proteins. Increased regulations of oxidoreductases, superoxide dismutase, thioredoxin, malate dehydrogenase, 2-oxoisovalerate dehydrogenase, 2-oxoisovalerate dehydrogenase, and dihydrolipoyl dehydrogenase were observed. The cellular defense-related protein responses were potent against Cd stress. The results conclude that Sphingomonas sp. LK11 reprogram its amino acids and proteomic expressions and maintain a steady growth during Cd stress. Using such phytohromones producing endophytic bacterium can be ideal approach to increase the phytoextraction potential of metal remediating plants. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 887-896, 2016.
authors.affiliation: Department of Biological Sciences and Chemistry, University of Nizwa, 66, Oman.|UoN Chair of Oman's Medicinal Plants and Marine Natural Products, University of Nizwa, 616, Oman.
authors.forename: Abdul Latif
authors.initials: AL
authors.lastname: Khan
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Republic of Korea.
authors.forename: Ihsan
authors.initials: I
authors.lastname: Ullah
authors.affiliation: Department of Biological Sciences and Chemistry, University of Nizwa, 66, Oman.
authors.forename: Javid
authors.initials: J
authors.lastname: Hussain
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Republic of Korea.
authors.forename: Sang-Mo
authors.initials: SM
authors.lastname: Kang
authors.affiliation: Department of Biological Sciences and Chemistry, University of Nizwa, 66, Oman.|UoN Chair of Oman's Medicinal Plants and Marine Natural Products, University of Nizwa, 616, Oman.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Al-Harrasi
authors.affiliation: Department of Biological Sciences and Chemistry, University of Nizwa, 66, Oman.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Al-Rawahi
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Republic of Korea.
authors.forename: In-Jung
authors.initials: IJ
authors.lastname: Lee
mesh_terms: D000601:Amino Acids, Essential / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism*; D003470:Culture Media; D060026:Endophytes; D015870:Gene Expression / Q000187:drug effects; D008670:Metals / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D040901:Proteomics; D012269:Ribosomal Proteins / Q000378:metabolism; D020578:Sphingomonas / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000601:Amino Acids, Essential; D000975:Antioxidants; D003470:Culture Media; D008670:Metals; D018832:Molecular Chaperones; D012269:Ribosomal Proteins; D002104:Cadmium
keywords: Sphingomonas sp. LK11; bioaccumulation; cadmium stress; endophytism; protein profile