The effect of carabrone on mitochondrial respiratory chain complexes in Gaeumannomyces graminis.

AIMS: To evaluate the effect of carabrone on mitochondrial respiratory chain complexes in Gaeumannomyces graminis to identify carabrone targets.

METHODS AND RESULTS: The influence of carabrone on mitochondria in G. graminis mycelia was determined, and the activity of complexes I-V, citrate synthase, and respiratory chain complexes I+III and II+III was evaluated following treatment with 30% effective concentration (EC30 ) as well as EC50 and EC70 of carabrone for 0, 6, 12 and 24 h. Quantitative real-time PCR analysis of the relative expression of genes encoding mitochondrial respiratory chain complexes was then conducted. Carabrone treatment influenced the activity of mitochondrial respiratory chain complexes III, I+III, and II+III in G. graminis in a dose- and time-dependent manner with a marked decrease (c. 50% compared to the control) in mitochondrial respiratory chain complex III activity following treatment with carabrone at the EC50 . The GgCyc1 was downregulated following carabrone treatment at the EC50 , and the other genes were upregulated with respect to the control.

CONCLUSIONS: This study showed that mitochondrial respiratory chain complex III in G. graminis is highly sensitive to carabrone and is a potential target of this botanical fungicidal agent.

SIGNIFICANCE AND IMPACT OF THE STUDY: Carabrone is a promising botanical fungicidal agent that is environmentally friendly and can control plant diseases and reduce chemical fungicides in agricultural production.