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Analyzing Arabidopsis thaliana root proteome provides insights into the molecular bases of enantioselective imazethapyr toxicity.

Qian H, Lu H, Ding H, Lavoie M, Li Y, Liu W, Fu Z - Sci Rep (2015)

Bottom Line: Here, we exposed the model plant Arabidospsis thaliana to trace S- and R-IM enantiomer concentrations and examined IM toxicity effects on the root proteome using iTRAQ.Bioinformatics and physiological analyses suggested that IM reduced the BCAA tissue content not only by strongly suppressing BCAA synthesis but also by increasing BCAA catabolism.The present study shed new light on the multiple toxicity mechanisms of a selective herbicide on a model plant.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. of China [2] College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, P. R. of China.

ABSTRACT
Imazethapyr (IM) is a widely used chiral herbicide that inhibits the synthesis of branched-chain amino acids (BCAAs). IM is thought to exert its toxic effects on amino acid synthesis mainly through inhibition of acetolactate synthase activity, but little is known about the potential effects of IM on other key biochemical pathways. Here, we exposed the model plant Arabidospsis thaliana to trace S- and R-IM enantiomer concentrations and examined IM toxicity effects on the root proteome using iTRAQ. Conventional analyses of root carbohydrates, organic acids, and enzyme activities were also performed. We discovered several previously unknown key biochemical pathways targeted by IM in Arabidospsis. 1,322 and 987 proteins were differentially expressed in response to R- and S-IM treatments, respectively. Bioinformatics and physiological analyses suggested that IM reduced the BCAA tissue content not only by strongly suppressing BCAA synthesis but also by increasing BCAA catabolism. IM also affected sugar and starch metabolism, changed the composition of root cell walls, increased citrate production and exudation, and affected the microbial community structure of the rhizosphere. The present study shed new light on the multiple toxicity mechanisms of a selective herbicide on a model plant.

No MeSH data available.


Related in: MedlinePlus

The organic acid levels and enzyme activities in the TCA cycle after IM enantiomer exposure.Pyruvate content (A) malate content (B) citrate content (C) amount of citrate exuded in the external medium (D) Activity of PEPC (E) and MDH (F). * and ** indicate that the values are significantly different from those of the control plants at p < 0.05 and p < 0.01, respectively. # and ## indicate that the numbers are significantly different from those of the S-IM-exposed plants at p < 0.05 and p < 0.01, respectively. Error bars are standard errors of four biological replicates.
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f4: The organic acid levels and enzyme activities in the TCA cycle after IM enantiomer exposure.Pyruvate content (A) malate content (B) citrate content (C) amount of citrate exuded in the external medium (D) Activity of PEPC (E) and MDH (F). * and ** indicate that the values are significantly different from those of the control plants at p < 0.05 and p < 0.01, respectively. # and ## indicate that the numbers are significantly different from those of the S-IM-exposed plants at p < 0.05 and p < 0.01, respectively. Error bars are standard errors of four biological replicates.

Mentions: The mean pyruvate concentration increased to 1.7-fold that of the control after treatment with R-IM (Fig. 4A). iTRAQ analyses revealed that R-IM treatment greatly increased the expression of several TCA-cycle enzymes, e.g., isocitrate dehydrogenase (ICDH, AT1G54340.1), 2-oxoglutarate dehydrogenase (AT5G65750.1), succinyl-CoA ligase [ADP-forming] subunit alpha-1(AT5G08300.1), and malate dehydrogenase (MDH, AT5G56720.1) (Table S1). Moreover, R-IM repressed the abundance of ATP-citrate lyase A-1 (ACLA-1, AT1G10670.4), which is a key enzyme producing acetyl-CoA from citrate during fatty acid synthesis in the chloroplast. In contrast, S-IM increased the expression of ATP-citrate lyase A-3 (ACLA-3, AT1G09430.1).


Analyzing Arabidopsis thaliana root proteome provides insights into the molecular bases of enantioselective imazethapyr toxicity.

Qian H, Lu H, Ding H, Lavoie M, Li Y, Liu W, Fu Z - Sci Rep (2015)

The organic acid levels and enzyme activities in the TCA cycle after IM enantiomer exposure.Pyruvate content (A) malate content (B) citrate content (C) amount of citrate exuded in the external medium (D) Activity of PEPC (E) and MDH (F). * and ** indicate that the values are significantly different from those of the control plants at p < 0.05 and p < 0.01, respectively. # and ## indicate that the numbers are significantly different from those of the S-IM-exposed plants at p < 0.05 and p < 0.01, respectively. Error bars are standard errors of four biological replicates.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4495388&req=5

f4: The organic acid levels and enzyme activities in the TCA cycle after IM enantiomer exposure.Pyruvate content (A) malate content (B) citrate content (C) amount of citrate exuded in the external medium (D) Activity of PEPC (E) and MDH (F). * and ** indicate that the values are significantly different from those of the control plants at p < 0.05 and p < 0.01, respectively. # and ## indicate that the numbers are significantly different from those of the S-IM-exposed plants at p < 0.05 and p < 0.01, respectively. Error bars are standard errors of four biological replicates.
Mentions: The mean pyruvate concentration increased to 1.7-fold that of the control after treatment with R-IM (Fig. 4A). iTRAQ analyses revealed that R-IM treatment greatly increased the expression of several TCA-cycle enzymes, e.g., isocitrate dehydrogenase (ICDH, AT1G54340.1), 2-oxoglutarate dehydrogenase (AT5G65750.1), succinyl-CoA ligase [ADP-forming] subunit alpha-1(AT5G08300.1), and malate dehydrogenase (MDH, AT5G56720.1) (Table S1). Moreover, R-IM repressed the abundance of ATP-citrate lyase A-1 (ACLA-1, AT1G10670.4), which is a key enzyme producing acetyl-CoA from citrate during fatty acid synthesis in the chloroplast. In contrast, S-IM increased the expression of ATP-citrate lyase A-3 (ACLA-3, AT1G09430.1).

Bottom Line: Here, we exposed the model plant Arabidospsis thaliana to trace S- and R-IM enantiomer concentrations and examined IM toxicity effects on the root proteome using iTRAQ.Bioinformatics and physiological analyses suggested that IM reduced the BCAA tissue content not only by strongly suppressing BCAA synthesis but also by increasing BCAA catabolism.The present study shed new light on the multiple toxicity mechanisms of a selective herbicide on a model plant.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Food Science and Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. of China [2] College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, P. R. of China.

ABSTRACT
Imazethapyr (IM) is a widely used chiral herbicide that inhibits the synthesis of branched-chain amino acids (BCAAs). IM is thought to exert its toxic effects on amino acid synthesis mainly through inhibition of acetolactate synthase activity, but little is known about the potential effects of IM on other key biochemical pathways. Here, we exposed the model plant Arabidospsis thaliana to trace S- and R-IM enantiomer concentrations and examined IM toxicity effects on the root proteome using iTRAQ. Conventional analyses of root carbohydrates, organic acids, and enzyme activities were also performed. We discovered several previously unknown key biochemical pathways targeted by IM in Arabidospsis. 1,322 and 987 proteins were differentially expressed in response to R- and S-IM treatments, respectively. Bioinformatics and physiological analyses suggested that IM reduced the BCAA tissue content not only by strongly suppressing BCAA synthesis but also by increasing BCAA catabolism. IM also affected sugar and starch metabolism, changed the composition of root cell walls, increased citrate production and exudation, and affected the microbial community structure of the rhizosphere. The present study shed new light on the multiple toxicity mechanisms of a selective herbicide on a model plant.

No MeSH data available.


Related in: MedlinePlus