Lead Tolerance and Accumulation in Hirschfeldia incana, a Mediterranean Brassicaceae from Metalliferous Mine Spoils

Abstract

Lead is a heavy metal of particular concern with respect to environmental quality and health. The lack of plant species that accumulate and tolerate Pb is a limiting factor to understand the molecular mechanisms involved in Pb tolerance. In this study we identified Hirschfeldia incana, a Brassicaceae collected from metalliferous mine spoils in Morocco, as a Pb accumulator plant. H. incana exhibited high Pb accumulation in mine soils and in hydroponic cultures. Major Pb accumulation occurred in the roots and a part of Pb translocated from the roots to the shoots, even to the siliques. These findings demonstrated that H. incana is a Pb accumulator species. The expression of several candidate genes after Pb-exposure was measured by quantitative PCR and two of them, HiHMA4 and HiMT2a, coding respectively for a P1B-type ATPase and a metallothionein, were particularly induced by Pb-exposure in both roots and leaves. The functional characterization of HiHMA4 and HiMT2a was achieved using Arabidopsis T-DNA insertional mutants. Pb content and primary root growth analysis confirmed the role of these two genes in Pb tolerance and accumulation. H. incana could be considered as a good experimental model to identify genes involved in lead tolerance and accumulation in plants.

Zinc, lead, and cadmium tolerance and accumulation in Cistus libanotis, Cistus albidus, and Cistus salviifolius: Perspectives on phytoremediation

“…salviifolius (Figure 2b), showing that the roots of all three species accumulated much more Pb than their aboveground parts. A similar trend has been observed in C. ladanifer (Kidd et al, 2004) and H. incana roots (Auguy et al, 2013; Fahr et al, 2015). This is a general pattern of Pb distribution in plants (Pourrut et al, 2011), possibly due to binding of Pb in cell wall polysaccharides of root cells (Fahr et al, 2013; Seregin & Ivanov, 1998).…”

Jacks of metal/metalloid chelation trade in plants—an overview

“…It plays a role in metal homeostasis during seed development and seed germination rather than in metal decontamination (Roosens et al, 2004 ; Maestri et al, 2010 ). The analysis of the expression of MT2a in A. thaliana , a non-Pb tolerant species, showed that were specifically over-expressed in roots by Pb-treatment (Auguy et al, 2013 ). MTs are extremely diverse in plants and T. caerulescens seems to be an excellent model to understand the adaptive significance of this phenomenon.…”

Lead Accumulation and Distribution at Cellular level in Native Plants Growing on Battery Wastes Contaminated Sites in Ibadan, Nigeria

“…Of about 450 plant species reported worldwide for phytoextraction, few of them are Pb hyperaccumulators while majority are for nickel and zinc. Knowledge on the application of phytoextraction strategy for the remediation of Pb-contaminated soils is therefore lacking [28,31]. This has been identified as a limiting factor in studying and understanding the molecular and genetic mechanisms involved in Pb tolerance [28].…”