The metal tolerance profile of Thlaspi goesingense is mimicked in Arabidopsis thaliana heterologously expressing serine acetyl-transferase.
BACKGROUND
The Ni hyperaccumulator Thlaspi goesingense is tolerant to Ni congruent with Zn, congruent with Co and slightly resistant to > Cd. We previously observed that elevated glutathione, driven by constitutive activation of serine acetyltransferase (SAT), plays a role in the Ni tolerance of T. goesingense.


RESULTS
Here we show that the elevated shoot concentration of glutathione, previously shown to cause elevated Ni tolerance in Arabidopsis thaliana heterologously expressing T. goesingense mitochondrial serine acetyltransferase (SATm), also causes tolerance to Co and Zn while slightly enhancing resistance to Cd. The level of tolerance afforded to each metal is ranked Ni congruent with Co, > Zn > Cd. The Ni congruent with Co, > Zn tolerances are positively correlated with both the accumulation of glutathione (GSH) and the ability to resist the oxidative damage induced by these different metals. Based on the relative concentrations of each metal used a relatively low level of resistance to Cd was observed in both T. goesingense and TgSATm expressing lines and Cd resistance was least correlated to GSH accumulation.


CONCLUSIONS
Such data supports the conclusion that elevated glutathione levels, driven by constitutively enhanced SAT activity in the hyperaccumulator T. goesingense, plays an important role in the Ni, Co and Zn tolerance of this and other Thlaspi species. The hyper-activation of S assimilation through SAT is an excellent strategy for engineering enhanced metal tolerance in transgenic plants potentially used for phytoremediation.
Center for Plant Environmental Stress Physiology, Purdue University, Horticulture and Landscape Architecture Department, West Lafayette, Indiana 47907, USA. John.Freeman@ColoState.edu
John L
JL
Freeman
David E
DE
Salt
D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D002104:Cadmium / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D005978:Glutathione / Q000378:metabolism / Q000494:pharmacology; D019216:Metals, Heavy / Q000494:pharmacology*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000502:physiology; D009532:Nickel / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D051050:Serine O-Acetyltransferase / Q000235:genetics / Q000378:metabolism*; D031227:Thlaspi / Q000235:genetics* / Q000378:metabolism; D015032:Zinc / Q000494:pharmacology
D019216:Metals, Heavy; D024101:Mitochondrial Proteins; D010940:Plant Proteins; D002104:Cadmium; D003035:Cobalt; D009532:Nickel; D051050:Serine O-Acetyltransferase; D005978:Glutathione; D015032:Zinc