Environmental Engineering Reference
In-Depth Information
14
Plant Selenium Metabolism: Genetic
Manipulation, Phytotechnological
Application
s, and Ecological Implications
ElizabethA.H.Pilon-Smits
CONTENTS
Introduction.......................................................................................................... 295
Se.Metabolism.in.Plants...................................................................................... 297
Manipulation.of.Plant.Se.Metabolism.Using.Genetic.Engineering.............. 299
New.Insight.into.Se.Tolerance.and.Accumulation.Mechanisms.from.
Integrated.Genomic,.Genetic,.and.Biochemical.Approaches........................ 302
Ecological.Aspects.of.Se.Phytoremediation..................................................... 303
Contribution.of.Microbes.to.Plant.Se.Uptake.and.Volatilization............. 303
Effects.of.Plant.Se.on.Ecological.Partners................................................... 304
Future.Prospects.................................................................................................. 307
Acknowledgment................................................................................................ 307
References............................................................................................................. 308
Introduction
The. element. selenium. (Se). is. chemically. similar. to. sulfur. (S).. For. this. rea-
son. plants. and. other. organisms. mistakenly. take. up. and. metabolize. Se. via.
S. transporters. and. biochemical. pathways.. This. can. cause. toxicity. due. to. a.
combination.of.(1).oxidative.stress.caused.directly.by.selenocompounds.and.
(2).replacement.of.S.by.Se.in.proteins.and.other.S.compounds,.which.disrupts.
their.function..On.the.other.hand,.Se.is.an.essential.trace.element.for.many.
organisms,. including. mammals,. many. bacteria,. and. certain. green. algae.
(Stadtman.1990,.1996,.Fu.et.al..2002)..For.higher.plants,.Se.has.been.reported.
to.be.a.beneicial.nutrient,.but.it.has.not.been.shown.to.be.essential.(Cartes.
et. al.. 2005,. Djanaguiraman. et. al.. 2005,. Hartikainen. 2005,. Lyons. et. al.. 2009,.
Pilon-Smits.et.al..2009)..Organisms.that.require.Se.produce.essential.proteins.
that.contain.selenocysteine.(SeCys).in.their.active.site..To.date,.no.selenopro-
teins. have.been.conirmed. to.exist. in.higher. plants. (Novoselov. et. al.. 2002)..
295
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