Present address: Institut de Recherche sur la Biologie de l’Insecte, UMR CNRS 6035, Faculté des Sciences, Bâtiment I, 31 Avenue Monge, 37200 Tours, France
Merging methods in molecular and ecological genetics to study the adaptation of plants to anthropogenic metal-polluted sites: implications for phytoremediation
Article first published online: 4 SEP 2007
© 2007 The Authors. Journal compilation © 2007 Blackwell Publishing Ltd
Volume 17, Issue 1, pages 108–119, January 2008
How to Cite
PAUWELS, M., WILLEMS, G., ROOSENS, N., FRÉROT, H. and SAUMITOU-LAPRADE, P. (2008), Merging methods in molecular and ecological genetics to study the adaptation of plants to anthropogenic metal-polluted sites: implications for phytoremediation. Molecular Ecology, 17: 108–119. doi: 10.1111/j.1365-294X.2007.03486.x
Box 1 Definition of heavy-metal tolerance: a complex plant–environment interaction
Heavy-metal tolerance is the capacity of a plant to survive and reproduce in a highly metal-polluted soil, toxic for most other plants (Antonovics et al. 1971; Macnair 1987).
How do metal-tolerant plants respond to high metal concentrations?
Accumulation and exclusion are the two main ways in which plants respond to increasing soil-metal levels, reflected by the metal concentrations in aerial plant parts. Excluders loose the control of metal translocation to aerial parts beyond a threshold of soil metal level. Hyperaccumulators are particular accumulators that show elevated metal concentrations in aerial parts mainly as a result of an enhanced root-to-shoot translocation (Lasat et al. 1996; Clemens 2001).
Research focus: What are the physiological pathways responsible for heavy-metal tolerance? Are they different between excluders, indicators and (hyper) accumulators?
Is metal tolerance specific of plants from polluted soils?
‘Non-tolerant,’ or ‘metal-tolerant’ refers to the plant genotype while ‘non-metalliferous’ or ‘metalliferous’ refers to the soil type. Non-metallicolous populations (NM) develop on non-metalliferous soils and metallicolous populations (M) develop on metalliferous soils. Non metallophytes (A category) never occur on metalliferous soils (no M populations). Pseudometallophyte (B and C categories) have metallicolous and non-metallicolous populations in various relative proportions (NM > M or NM < M). Eumetallophytes (D category) always occur on metalliferous soils (metalloendemics, no NM population).
Research focus: What is the origin of the genetic variability of heavy-metal tolerance? How do metal tolerant genotypes maintain in non-metalliferous soils?
- Issue published online: 4 SEP 2007
- Article first published online: 4 SEP 2007
- Received 8 February 2007; revision accepted 4 July 2007
- Arabidopsis halleri;
- QTL mapping;
Metallophyte species that occur naturally on metal-enriched soils represent major biological resources for the improvement of phytoremediation, a benign and cost-effective technology that uses plants to clean up anthropogenic metal-polluted soils. Within the last decade, molecular genetic studies carried out on several model organisms (including Arabidopsis halleri) have considerably enhanced our understanding of metal tolerance and hyperaccumulation in plants, but the identification of the genes of interest for phytoremediation purposes remains a challenge. To meet this challenge, we propose to combine ‘-omics’ with molecular ecology methods. Using A. halleri, we confronted molecular genetic results with: (i) within-species polymorphism and large-scale population differentiation for zinc tolerance; (ii) the demographical context (e.g. migration pattern) of the species for zinc tolerance evolution; (iii) the Quantitative Trait Loci (QTL) analysis of the genetic architecture for zinc tolerance; and (iv) the fine-scale dissection of identified QTL regions, to discuss more precisely the nature of the genes potentially involved in the adaptation to zinc-polluted soils.