Overexpression of selenocysteine methyltransferase in Arabidopsis and Indian mustard increases selenium tolerance and accumulation.
A major goal of phytoremediation is to transform fast-growing plants with genes from plant species that hyperaccumulate toxic trace elements. We overexpressed the gene encoding selenocysteine methyltransferase (SMT) from the selenium (Se) hyperaccumulator Astragalus bisulcatus in Arabidopsis and Indian mustard (Brassica juncea). SMT detoxifies selenocysteine by methylating it to methylselenocysteine, a nonprotein amino acid, thereby diminishing the toxic misincorporation of Se into protein. Our Indian mustard transgenic plants accumulated more Se in the form of methylselenocysteine than the wild type. SMT transgenic seedlings tolerated Se, particularly selenite, significantly better than the wild type, producing 3- to 7-fold greater biomass and 3-fold longer root lengths. Moreover, SMT plants had significantly increased Se accumulation and volatilization. This is the first study, to our knowledge, in which a fast-growing plant was genetically engineered to overexpress a gene from a hyperaccumulator in order to increase phytoremediation potential.
LeDuc
Danika L
DL
Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA.
Tarun
Alice S
AS
Montes-Bayon
Maria
M
Meija
Juris
J
Malit
Michele F
MF
Wu
Carol P
CP
AbdelSamie
Manal
M
Chiang
Chih-Yuan
CY
Tagmount
Abderrhamane
A
deSouza
Mark
M
Neuhierl
Bernhard
B
Böck
August
A
Caruso
Joseph
J
Terry
Norman
N
D000222:Adaptation, Physiological / Q000235:genetics* / Q000502:physiology; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009149:Mustard Plant / Q000201:enzymology* / Q000235:genetics; D016566:Organoselenium Compounds / Q000378:metabolism; D030821:Plants, Genetically Modified; D012643:Selenium / Q000378:metabolism*; D017279:Selenocysteine / Q000031:analogs & derivatives; D014835:Volatilization
D016566:Organoselenium Compounds; D017279:Selenocysteine; D008780:Methyltransferases; C100751:selenocysteine methyltransferase; D012643:Selenium; D003545:Cysteine; C002979:selenomethylselenocysteine