Morphological Responses and Gene Expression of Grain Amaranth (Amaranthus spp.) Growing under Cd.

Veronika Lancíková,Ján Gažo,Andrea Hricová,Marián Tomka,Jana Žiarovská

doi:10.3390/plants9050572

Abstract

Phytoremediation efficiency depends on the ability of plants to accumulate, translocate and resist high levels of metals without symptoms of toxicity. This study was conducted to evaluate the potential of grain amaranth for remediation of soils contaminated with Cd. Three grain amaranth varieties, “Pribina” (A. cruentus), “Zobor” (A. hypochondriacus x A. hybridus) and Plainsman (A. hypochondriacus x A. hybridus) were tested under different level of Cd (0, 5, 10 and 15 mg/L) in a hydroponic experimental treatment. All could be classified as Cd excluders or Cd-hypertolerant varieties able to grow and accumulate significant amounts of Cd from the hydroponic solution, preferentially in the roots. Under the highest level of Cd exposure, qRT-PCR expression analysis of five stress-related genes was examined in above- and below-ground biomass. The results show that the Cd concentration significantly increased the mRNA level of chitinase 5 (Chit 5) in amaranth roots as the primary site of metal stress. The involvement of phytochelatin synthase (PCS1) in Cd detoxification is suggested. Based on our findings, we can conclude that variety “Pribina” is the most Cd-tolerant among three tested and can be expected to be used in the phytomanagement of Cd loaded soils as an effective phytostabiliser.

Highlights

Soil contamination by heavy metals (HMs) has become a serious threat to the human population, agriculture and food security
We examined Cd absorption capability as another potential of new grain varieties “Pribina” (A. cruentus L.) and “Zobor” (A. hypochondriacus x A. hybridus) that are preferentially used for consumption and could be potentially applied in phytoremediation
Slovak varieties “Pribina” (A. cruentus) and “Zobor” (A. hypochondriacus x A. hybridus) were both previously bred at the home institute by mutation breeding [71,72], and the commercially most preferred variety was Plainsman (A. hypochondriacus x A. hybridus)

Summary

Introduction

Soil contamination by heavy metals (HMs) has become a serious threat to the human population, agriculture and food security. The most dangerous are nonessential metals such as cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As). These elements have no biochemical or physiological function and cause significant damage to living systems, unlike essential metals (Mn, Zn, Fe and Cu) which are beneficial in low concentrations [3]. Within the European Union, Tóth et al [8] investigated the presence of HMs in topsoil samples collected from more than 20,000 locations. This unique soil heavy metal assessment showed that agricultural land of about 137,000 km (6.24%) would need additional measures and possible remediation

Methods

Results

Discussion

Conclusion