Quinclorac-habituation of bean (Phaseolus vulgaris) cultured cells is related to an increase in their antioxidant capacity

• Bean callus-cultured cells treated with10 µM quinclorac reduced the relative growth rate and increased in lipid peroxidation.
• Quinclorac-habituation is associated with the control of quinclorac-induced oxidative damage.
• Quinclorac-habituated cells are featured by an enhanced antioxidant status.
• The antioxidant status of quinclorac-habituated cells was maintained after removing the herbicide.
• Class-III peroxidase and superoxide dismutase activities seem to play a major role in quinclorac-habituation.

The habituation of bean cells to quinclorac did not rely on cell wall modifications, contrary to what it was previously observed for the well-known cellulose biosynthesis inhibitors dichlobenil or isoxaben. The aim of the present study was to investigate whether or not the bean cells habituation to quinclorac is related to an enhancement of antioxidant activities involved in the scavenging capacity of reactive oxygen species. Treating non-habituated bean calluses with 10 μM quinclorac reduced the relative growth rate and induced a two-fold increase in lipid peroxidation. However, the exposition of quinclorac-habituated cells to a concentration of quinclorac up to 30 μM neither affected their growth rate nor increased their lipid peroxidation levels. Quinclorac-habituated calluses had significantly higher constitutive levels of three antioxidant activities (class-III peroxidase, glutathione reductase, and superoxide dismutase) than those observed in non-habituated calluses, and the treatment of habituated calluses with 30 μM quinclorac significantly increased the level of class III-peroxidase and superoxide dismutase. The results reported here indicate that the process of habituation to quinclorac in bean callus-cultured cells is related, at least partially, to the development of a stable antioxidant capacity that enables them to cope with the oxidative stress caused by quinclorac. Class-III peroxidase and superoxide dismutase activities could play a major role in the quinclorac-habituation. Changes in the antioxidant status of bean cells were stable, since the increase in the antioxidant activities were maintained in quinclorac-dehabituated cells.

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