In vivo assay to monitor flavonoid uptake across plant cell membranes

• A new methodological protocol to follow in vivo flavonoid transport.
• Easy-to-use and reliable fluorescence assay utilizing DPBA as a probe.
• Quercetin quantification in grapevine cell extracts.

Flavonoids represent one of the most important molecules of plant secondary metabolism, playing many different biochemical and physiological roles. Although their essential role in plant life and human health has been elucidated by many studies, their subcellular transport and accumulation in plant tissues remains unclear. This is due to the absence of a convenient and simple method to monitor their transport. In the present work, we suggest an assay able to follow in vivo transport of quercetin, the most abundant flavonoid in plant tissues. This uptake was monitored using 2-aminoethoxydiphenyl borate (DPBA), a fluorescent probe, in non-pigmented Vitis vinifera cell cultures.