During their life cycle, plants can undergo simultaneous attack by different pathogens that produce various toxins. It is well known that in some plant-fungal interactions, mycotoxins play an important role in pathogenesis and induce a reactive oxygen species (ROS) increase. Plants counteract the over-accumulation of ROS by reinforcing the defence systems. T-2 toxin (T-2) and beauvericin (BEA) mycotoxins are produced by some Fusarium species and have different chemical structures, mechanisms of action and biological activities. In this study, the individual and combined effects of the two toxins on defence systems such as the ascorbate-glutathione cycle and peroxidases were evaluated in cherry tomato shoots. Hydrogen peroxide content as an index of oxidative stress was also measured. Inhibitory effects on ascorbate peroxidase, dehydroascorbate reductase and ascorbate, and stimulatory effects on glutathione reductase, monodehydroascorbate reductase and reduced glutathione were observed when tomato plants were simultaneously treated with BEA and T-2. The trends of these biochemical parameters highlight the presence of a range of defence mechanisms activated by plants in response to mycotoxins. The interaction between BEA and T-2 resulting in synergistic and/or antagonistic effects on the studied defence systems is also discussed. It is concluded that the effects of these mycotoxins alone are not predictive of their combined effects.
Combined effect of beauvericin and T-2 toxin on antioxidant defence systems in cherry tomato shoots
PACIOLLA, Costantino;
2014-01-01
Abstract
During their life cycle, plants can undergo simultaneous attack by different pathogens that produce various toxins. It is well known that in some plant-fungal interactions, mycotoxins play an important role in pathogenesis and induce a reactive oxygen species (ROS) increase. Plants counteract the over-accumulation of ROS by reinforcing the defence systems. T-2 toxin (T-2) and beauvericin (BEA) mycotoxins are produced by some Fusarium species and have different chemical structures, mechanisms of action and biological activities. In this study, the individual and combined effects of the two toxins on defence systems such as the ascorbate-glutathione cycle and peroxidases were evaluated in cherry tomato shoots. Hydrogen peroxide content as an index of oxidative stress was also measured. Inhibitory effects on ascorbate peroxidase, dehydroascorbate reductase and ascorbate, and stimulatory effects on glutathione reductase, monodehydroascorbate reductase and reduced glutathione were observed when tomato plants were simultaneously treated with BEA and T-2. The trends of these biochemical parameters highlight the presence of a range of defence mechanisms activated by plants in response to mycotoxins. The interaction between BEA and T-2 resulting in synergistic and/or antagonistic effects on the studied defence systems is also discussed. It is concluded that the effects of these mycotoxins alone are not predictive of their combined effects.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
