Integrative physiological and transcriptome analyses provide insights into the Cadmium (Cd) tolerance of a Cd accumulator: Erigeron canadensis

Abstract

Cadmium (Cd) is a highly toxic pollutant in soil and water that severely hampers the growth and reproduction of plants. Phytoremediation has been presented as a cost-effective and eco-friendly method for addressing heavy metal pollution. However, phytoremediation is restricted by the limited number of accumulators and the unknown mechanisms underlying heavy metal tolerance. In this study, we demonstrated that Erigeron canadensis (Asteraceae), with its strong adaptability, is tolerant to intense Cd stress (2 mmol/L CdCl2 solution). Moreover, E. canadensis exhibited a strong ability to accumulate Cd2+ when treated with CdCl2 solution. The activity of some antioxidant enzymes, as well as the malondialdehyde (MDA) level, was significantly increased when E. canadensis was treated with different CdCl2 solutions (0.5, 1, 2 mmol/L CdCl2). We found high levels of superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities under 1 mmol/L CdCl2 treatment. Comparative transcriptomic analysis identified 5,284 differentially expressed genes (DEGs) in the roots and 3,815 DEGs in the shoots after E. canadensis plants were exposed to 0.5 mM Cd. Functional annotation of key DEGs indicated that signal transduction, hormone response, and reactive oxygen species (ROS) metabolism responded significantly to Cd. In particular, the DEGs involved in auxin (IAA) and ethylene (ETH) signal transduction were overrepresented in shoots, indicating that these genes are mainly involved in regulating plant growth and thus likely responsible for the Cd tolerance. Overall, these results not only determined that E. canadensis can be used as a potential accumulator of Cd but also provided some clues regarding the mechanisms underlying heavy metal tolerance.

Transcriptome Profiling, Physiological and Biochemical Analyses Reveal Comprehensive Insights in Cadmium Stress in Brassica carinata L.

“…This suggests that the excessive addition of Cd hindered the effective transport of Cd in a short period of time. A similar result was also observed in Abelmoschus manihot and Erigeron canadensis [8,22,26]. Although the results of this study were only based on hydroponic conditions, B. carinata showed a potentially strong ability in terms of Cd accumulation.…”

“…The Pro content was processed with a commercially available testing kit following the guidelines of the manufacturer and assessed via a microplate reader at a UV wavelength of 520 nm. The method used to measure the chlorophyll content in the leaves was achieved through the extraction of acetone, as based on the work of Gan et al [8]. The leaves were ground with liquid nitrogen (0.1 g) in the absence of light.…”

“…These enzymes, such as superoxide dismutase (SOD), glutathione reductase (GR), peroxidase (POD), and ascorbate peroxidase (APX), are capable of efficiently reducing the presence of reactive oxygen species (ROS) in plants [7]. In addition, proline (Pro) has been demonstrated to decrease lipid peroxidation and free radical levels, thereby preserving the integrity of the cell membrane in plants exposed to Cd stress [8]. The adsorption, translocation, and accumulation of heavy metals into plant cells generally depend on the following processes: binding and trapping to the root cell wall, transport into the cytoplasm, and sequestration into leaf vacuoles [2].…”

Transcriptome Analysis Reveals the Stress Tolerance Mechanisms of Cadmium in Zoysia japonica

“…For example, 110.07 Gb of clean data and 63,957 unigenes were acquired from the hyperaccumulator Phytolacca americana after the Cd stress treatment [25]. In the Cd accumulator Erigeron canadensis, 12 cDNA libraries were constructed, and a total of 89.51 Gb of clean reads were obtained after 0.5 mmol/L of Cd treatment [26]. In the hyperaccumulator plant Noccaea caerulescens, transcriptomes were assembled using the Trinity de novo assembler and annotated along with the predicted protein sequences [27].…”

Identification, Evolutionary Dynamics, and Gene Expression Patterns of the ACP Gene Family in Responding to Salt Stress in Brassica Genus

“…Specific quantitative analysis primers were designed using NCBI, with Actin (used by [64]) serving as a control (Table S6). The FQD-48 X real-time fluorescence quantitative PCR system was employed to assess gene expression levels in this study, following the method of [65]. Three biological replicates and three technical repeats per gene were prepared.…”