Blue-green fluorescence during hypersensitive cell death arises from phenylpropanoid deydrodimers.

Infection of Arabidopsis with avirulent and exposure to nitrogen dioxide (NO) both trigger hypersensitive cell death (HCD) that is characterized by the emission of bright blue-green (BG) autofluorescence under UV illumination. The aim of our current work was to identify the BG fluorescent molecules and scrutinize their biosynthesis, localization, and functions during the HCD. Compared with wild-type (WT) plants, the phenylpropanoid-deficient mutant developed normal HCD except for the absence of BG fluorescence.