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Physiological and proteomics analyses reveal the mechanism of Eichhornia crassipes tolerance to high-concentration cadmium stress compared with Pistia stratiotes.

Li X, Zhou Y, Yang Y, Yang S, Sun X, Yang Y - PLoS ONE (2015)

Bottom Line: Cadmium (Cd) pollution is an environmental problem worldwide.As a result, E. crassipes could maintain more stable physiological parameters than P. stratiotes.In addition, antioxidant enzymes played important roles in ROS detoxification.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; China Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China; University of Chinese Academy of Sciences, Beijing 100049, China.

ABSTRACT
Cadmium (Cd) pollution is an environmental problem worldwide. Phytoremediation is a convenient method of removing Cd from both soil and water, but its efficiency is still low, especially in aquatic environments. Scientists have been trying to improve the ability of plants to absorb and accumulate Cd based on interactions between plants and Cd, especially the mechanism by which plants resist Cd. Eichhornia crassipes and Pistia stratiotes are aquatic plants commonly used in the phytoremediation of heavy metals. In the present study, we conducted physiological and biochemical analyses to compare the resistance of these two species to Cd stress at 100 mg/L. E. crassipes showed stronger resistance and was therefore used for subsequent comparative proteomics to explore the potential mechanism of E. crassipes tolerance to Cd stress at the protein level. The expression patterns of proteins in different functional categories revealed that the physiological activities and metabolic processes of E. crassipes were affected by exposure to Cd stress. However, when some proteins related to these processes were negatively inhibited, some analogous proteins were induced to compensate for the corresponding functions. As a result, E. crassipes could maintain more stable physiological parameters than P. stratiotes. Many stress-resistance substances and proteins, such as proline and heat shock proteins (HSPs) and post translational modifications, were found to be involved in the protection and repair of functional proteins. In addition, antioxidant enzymes played important roles in ROS detoxification. These findings will facilitate further understanding of the potential mechanism of plant response to Cd stress at the protein level.

No MeSH data available.


Related in: MedlinePlus

Comparative proteomics analyses of four E. crassipes samples treated with 100 mg/L Cd for different times.A: Representative 2-DE (the control sample of the first set of gel images) showing spot numbers of identified proteins. B: Hierarchical clustering of the identified protein expression profiles of different samples. Different colors correspond to the protein log-transformed fold-change ratios depicted in the bar on the left of the figure. C: Venn diagram analysis of differentially expressed proteins of each treated sample compared with the control sample (0d). “+” and “-” represent up-regulated and down-regulated proteins, respectively.
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pone.0124304.g005: Comparative proteomics analyses of four E. crassipes samples treated with 100 mg/L Cd for different times.A: Representative 2-DE (the control sample of the first set of gel images) showing spot numbers of identified proteins. B: Hierarchical clustering of the identified protein expression profiles of different samples. Different colors correspond to the protein log-transformed fold-change ratios depicted in the bar on the left of the figure. C: Venn diagram analysis of differentially expressed proteins of each treated sample compared with the control sample (0d). “+” and “-” represent up-regulated and down-regulated proteins, respectively.

Mentions: To further explore the underlying mechanism of E. crassipes tolerance toward Cd stress, the leaf proteomes of E. crassipes samples were evaluated by two-dimensional electrophoresis (2-DE). Each sample was replicated three times (S1, S2 and S3 Figs), and more than 500 protein spots were detected within each sample after staining. Of these, 87 showed increased expression (>1.50) or decreased expression (<0.67) in treated samples (2–5d) relative to the control (0d). Ultimately, 59 differentially expressed proteins (Fig 5A) were successfully identified by MALDI-TOF-MS/MS analysis and the National Center for Biotechnology Information (NCBI) nonredundant protein database (Table 1). Hierarchical cluster analysis was conducted to categorize the identified proteins that showed differential expression profiles in response to Cd stress (Fig 5B). Venn diagram analysis was used to reflect change patterns in proteins from treated samples (2–5d) relative to the control (0d) (Fig 5C). The results showed that up-regulation was much greater than down-regulation (Fig 5C), and that proteins were mainly affected during the later stage (3 or 5d) of Cd stress (Fig 5C).


Physiological and proteomics analyses reveal the mechanism of Eichhornia crassipes tolerance to high-concentration cadmium stress compared with Pistia stratiotes.

Li X, Zhou Y, Yang Y, Yang S, Sun X, Yang Y - PLoS ONE (2015)

Comparative proteomics analyses of four E. crassipes samples treated with 100 mg/L Cd for different times.A: Representative 2-DE (the control sample of the first set of gel images) showing spot numbers of identified proteins. B: Hierarchical clustering of the identified protein expression profiles of different samples. Different colors correspond to the protein log-transformed fold-change ratios depicted in the bar on the left of the figure. C: Venn diagram analysis of differentially expressed proteins of each treated sample compared with the control sample (0d). “+” and “-” represent up-regulated and down-regulated proteins, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401520&req=5

pone.0124304.g005: Comparative proteomics analyses of four E. crassipes samples treated with 100 mg/L Cd for different times.A: Representative 2-DE (the control sample of the first set of gel images) showing spot numbers of identified proteins. B: Hierarchical clustering of the identified protein expression profiles of different samples. Different colors correspond to the protein log-transformed fold-change ratios depicted in the bar on the left of the figure. C: Venn diagram analysis of differentially expressed proteins of each treated sample compared with the control sample (0d). “+” and “-” represent up-regulated and down-regulated proteins, respectively.
Mentions: To further explore the underlying mechanism of E. crassipes tolerance toward Cd stress, the leaf proteomes of E. crassipes samples were evaluated by two-dimensional electrophoresis (2-DE). Each sample was replicated three times (S1, S2 and S3 Figs), and more than 500 protein spots were detected within each sample after staining. Of these, 87 showed increased expression (>1.50) or decreased expression (<0.67) in treated samples (2–5d) relative to the control (0d). Ultimately, 59 differentially expressed proteins (Fig 5A) were successfully identified by MALDI-TOF-MS/MS analysis and the National Center for Biotechnology Information (NCBI) nonredundant protein database (Table 1). Hierarchical cluster analysis was conducted to categorize the identified proteins that showed differential expression profiles in response to Cd stress (Fig 5B). Venn diagram analysis was used to reflect change patterns in proteins from treated samples (2–5d) relative to the control (0d) (Fig 5C). The results showed that up-regulation was much greater than down-regulation (Fig 5C), and that proteins were mainly affected during the later stage (3 or 5d) of Cd stress (Fig 5C).

Bottom Line: Cadmium (Cd) pollution is an environmental problem worldwide.As a result, E. crassipes could maintain more stable physiological parameters than P. stratiotes.In addition, antioxidant enzymes played important roles in ROS detoxification.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; China Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China; University of Chinese Academy of Sciences, Beijing 100049, China.

ABSTRACT
Cadmium (Cd) pollution is an environmental problem worldwide. Phytoremediation is a convenient method of removing Cd from both soil and water, but its efficiency is still low, especially in aquatic environments. Scientists have been trying to improve the ability of plants to absorb and accumulate Cd based on interactions between plants and Cd, especially the mechanism by which plants resist Cd. Eichhornia crassipes and Pistia stratiotes are aquatic plants commonly used in the phytoremediation of heavy metals. In the present study, we conducted physiological and biochemical analyses to compare the resistance of these two species to Cd stress at 100 mg/L. E. crassipes showed stronger resistance and was therefore used for subsequent comparative proteomics to explore the potential mechanism of E. crassipes tolerance to Cd stress at the protein level. The expression patterns of proteins in different functional categories revealed that the physiological activities and metabolic processes of E. crassipes were affected by exposure to Cd stress. However, when some proteins related to these processes were negatively inhibited, some analogous proteins were induced to compensate for the corresponding functions. As a result, E. crassipes could maintain more stable physiological parameters than P. stratiotes. Many stress-resistance substances and proteins, such as proline and heat shock proteins (HSPs) and post translational modifications, were found to be involved in the protection and repair of functional proteins. In addition, antioxidant enzymes played important roles in ROS detoxification. These findings will facilitate further understanding of the potential mechanism of plant response to Cd stress at the protein level.

No MeSH data available.


Related in: MedlinePlus