Genes Associated with Heavy Metal Tolerance and Accumulation in Zn/Cd Hyperaccumulator Arabidopsis halleri:  A Genomic Survey with cDNA Microarray

Abstract

To survive in variable soil conditions, plants possess homeostatic mechanisms to maintain a suitable concentration of essential heavy metal ions. Certain plants, inhabiting heavy metal-enriched or -contaminated soil, thus are named hyperaccumulators. Studying hyperaccumulators has great potential to provide information for phytoremediation. To better understand the hyperaccumulating mechanism, we used an Arabidopsis cDNA microarray to compare the gene expression of the Zn/Cd hyperaccumulator Arabidopsis halleri and a nonhyperaccumulator, Arabidopsis thaliana. By analyzing the expression of metal-chelators, antioxidation-related genes, and transporters, we revealed a few novel molecular features. We found that metallothionein 2b and 3, APX and MDAR4 in the ascorbate-glutathione pathway, and certain metal transporters in P(1B)-type ATPase, ZIP, Nramp, and CDF families, are expressed at higher levels in A. halleri than in A. thaliana. We further validated that the enzymatic activity of ascorbate peroxidase and class III peroxidases are highly elevated in A. halleri. This observation positively correlates with the higher ability of A. halleri to detoxify H2O2 produced by cadmium and paraquat treatments. We thus suggest that higher peroxidase activities contribute to the heavy metal tolerance in A. halleri by alleviating the ROS damage. We have revealed genes that could be candidates for the future engineering of plants with large biomass for use in phytoremediation.

A Member of the Heavy Metal P-Type ATPase OsHMA5 Is Involved in Xylem Loading of Copper in Rice

“…HvHMA2 from barley and TaHMA2 from wheat showed similar functions as OsHMA2 in rice Tan et al, 2013). AhHMA3 in A. halleri, a Zn hyperaccumulator, is probably involved in high Zn accumulation (Becher et al, 2004;Chiang et al, 2006). Furthermore, AhHMA4 for Zn translocation showed a higher expression level (Chiang et al, 2006;Hanikenne et al, 2008).…”

“…AhHMA3 in A. halleri, a Zn hyperaccumulator, is probably involved in high Zn accumulation (Becher et al, 2004;Chiang et al, 2006). Furthermore, AhHMA4 for Zn translocation showed a higher expression level (Chiang et al, 2006;Hanikenne et al, 2008). On the other hand, TcHMA3 from ecotype Ganges of T. caerulescens, a Cd hyperaccumulator, plays an important role in the detoxification of Cd by sequestering Cd into the vacuole of the leaves (Ueno et al, 2011).…”

Heavy Metal Toxicity in Plants: Proteomics Approach

“…Her iki proteinin sentezindeki artış ağır metal stresine maruz bırakılmış bitki türlerinde belirlenmiştir (Alvarez et al 2009;Visioli et al 2012). Bununla birlikte, ağır metal konsantrasyonu ve MT içerikleri arasında korelasyon kurulamamasına karşın, bu proteinin içeriği Thlaspi caerulescens, Arabidopsis halleri, Silene paradoxa ve Silene vulgaris gibi hiperakümülatör türlerde belirlenmiştir (van Hoof et al 2001;Mengoni et al 2003;Chiang et al 2006;van de Mortel et al 2006;Visioli et al 2012). …”

Voltammetric Analysis of Phytochelatin Complexation in Ternary Metal Mixtures Supported by Multivariate Analysis and ESI‐MS

“…It is especially attractive because of its low cost and energy requirements. Research has focused upon gene expression involved within the process [5], efficiency improvement by the use of genetic engineered plants [6] or application of chelating agents [7].…”