Succinate dehydrogenase [ubiquinone] iron-sulfur subunit (SDHB) (SDHB)

Bcin15g03240, also known as the Succinate dehydrogenase [ubiquinone] iron-sulfur subunit (SDHB), is a vital enzyme component of the mitochondrial respiratory chain (Complex II) in the plant pathogenic fungus Botrytis cinerea [1]. It functions at the intersection of the tricarboxylic acid (TCA) cycle and the electron transport chain, catalyzing the oxidation of succinate to fumarate while transferring electrons to ubiquinone [1, 3]. This protein is the primary molecular target for the Succinate Dehydrogenase Inhibitor (SDHI) class of fungicides, which includes compounds like boscalid, fluopyram, and fluxapyroxad [2, 4]. These drugs bind to the ubiquinone-binding pocket (Q-site) formed by the SDHB, SDHC, and SDHD subunits, effectively halting ATP production and leading to fungal cell death [3]. Due to its essential role in energy metabolism, SDHB is a critical focus for agricultural disease management in crops affected by gray mold [2]. However, its efficacy is frequently challenged by the emergence of specific point mutations, such as H272R or H272Y, which confer high levels of fungicide resistance in field populations [2, 4]. Monitoring these genetic variations is essential for implementing effective anti-resistance strategies in the field [3].

Other names

Bcin15g03240Succinate dehydrogenase subunit BSDH2Iron-sulfur protein of complex IIBcSDHB

Inhibition of the succinate dehydrogenase enzyme by binding to the ubiquinone-binding site (Q-site), disrupting the mitochondrial electron transport chain and ATP production.