CYP2B6 and infection: In particular, the stimulation of β-sisterol to stigmasterol conversion that is observed in Arabidopsis after infection by Pseudomonas syringae has been shown to increase the susceptibility of the plant to infection and inhibition of stigmasterol synthesis (in P450 CYP710A1 mutants) enhances plant resistance to avirulent and virulent P. syringae strains (Griebel and Zeier, 2010).