title: Plant-based FRET biosensor discriminates environmental zinc levels.
abstract: Heavy metal accumulation in the environment poses great risks to flora and fauna. However, monitoring sites prone to accumulation poses scale and economic challenges. In this study, we present and test a method for monitoring these sites using fluorescent resonance energy transfer (FRET) change in response to zinc (Zn) accumulation in plants as a proxy for environmental health. We modified a plant Zn transport protein by adding flanking fluorescent proteins (FPs) and deploying the construct into two different species. In Arabidopsis thaliana, FRET was monitored by a confocal microscope and had a 1.4-fold increase in intensity as the metal concentration increased. This led to a 16.7% overall error-rate when discriminating between a control (1μm Zn) and high (10mm Zn) treatment after 96h. The second host plant (Populus tremula×Populu salba) also had greater FRET values (1.3-fold increase) when exposed to the higher concentration of Zn, while overall error-rates were greater at 22.4%. These results indicate that as plants accumulate Zn, protein conformational changes occur in response to Zn causing differing interaction between FPs. This results in greater FRET values when exposed to greater amounts of Zn and monitored with appropriate light sources and filters. We also demonstrate how this construct can be moved into different host plants effectively including one tree species. This chimeric protein potentially offers a method for monitoring large areas of land for Zn accumulation, is transferable among species, and could be modified to monitor other specific heavy metals that pose environmental risks.
authors.affiliation: School of Forest Resources, University of Arkansas at Monticello, Monticello, AR, USA. adamsj@uamont.edu
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Adams
authors.forename: Ardeshir
authors.initials: A
authors.lastname: Adeli
authors.forename: Chuan-Yu
authors.initials: CY
authors.lastname: Hsu
authors.forename: Richard L
authors.initials: RL
authors.lastname: Harkess
authors.forename: Grier P
authors.initials: GP
authors.lastname: Page
authors.forename: Claude W
authors.initials: CW
authors.lastname: Depamphilis
authors.forename: Emily B
authors.initials: EB
authors.lastname: Schultz
authors.forename: Cetin
authors.initials: C
authors.lastname: Yuceer
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods*; D027682:Cation Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004784:Environmental Monitoring / Q000379:methods; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D008164:Luminescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D032107:Populus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis* / Q000493:pharmacokinetics; D015032:Zinc / Q000032:analysis* / Q000493:pharmacokinetics
chemical_list: D027682:Cation Transport Proteins; D008164:Luminescent Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D012989:Soil Pollutants; C408070:ZNT1 zinc transporter, Thlaspi caerulescens; D015032:Zinc