Phytochelatin Synthesis Promotes Leaf Zn Accumulation of Arabidopsis thaliana Plants Grown in Soil with Adequate Zn Supply and is Essential for Survival on Zn-Contaminated Soil.
Phytochelatin (PC) synthesis is essential for the detoxification of non-essential metals such as cadmium (Cd). In vitro experiments with Arabidopsis thaliana seedlings had indicated a contribution to zinc (Zn) tolerance as well. We addressed the physiological role of PC synthesis in Zn homeostasis of plants under more natural conditions. Growth responses, PC accumulation and leaf ionomes of wild-type and AtPCS1 mutant plants cultivated in different soils representing adequate Zn supply, Zn deficiency and Zn excess were analyzed. Growth on Zn-contaminated soil triggers PC synthesis and is strongly impaired in PC-deficient mutants. In fact, the contribution of AtPCS1 to tolerating Zn excess is comparable with that of the major Zn tolerance factor MTP1. For plants supplied with a normal level of Zn, a significant reduction in leaf Zn accumulation of AtPCS1 mutants was detected. In contrast, AtPCS1 mutants grown under Zn-limited conditions showed wild-type levels of Zn accumulation, suggesting the operation of distinct Zn translocation pathways. Contrasting phenotypes of the tested AtPCS1 mutant alleles upon growth in Zn- or Cd-contaminated soil indicated differential activation of PC synthesis by these metals. Experiments with truncated versions identified a part of the AtPCS1 protein required for the activation by Zn but not by Cd.
Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany.
Tanja
T
Kühnlenz
Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany.
Christian
C
Hofmann
Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany.|Present address: Department of Public Health, School of Pharmacy, Kitasato University, Tokyo, Japan.
Shimpei
S
Uraguchi
Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany.
Holger
H
Schmidt
Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany.
Stefanie
S
Schempp
Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany.
Michael
M
Weber
Purdue University, Horticulture and Landscape Architecture, West Lafayette, IN, USA.
Brett
B
Lahner
Purdue University, Horticulture and Landscape Architecture, West Lafayette, IN, USA.|Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK.
David E
DE
Salt
Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany stephan.clemens@uni-bayreuth.
Stephan
S
Clemens
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism; D054811:Phytochelatins / Q000096:biosynthesis* / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000633:toxicity*; D015032:Zinc / Q000378:metabolism*
D029681:Arabidopsis Proteins; D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D054811:Phytochelatins; D015032:Zinc
Arabidopsis thaliana; Cadmium; Metal homeostasis; Metal tolerance; Micronutrients; Zinc