Flavanone-7-O-glucosyltransferase activity from Petunia hybrida

Area of Science:

• Biochemistry
• Plant Science
• Enzymology

Background:

• Citrus species accumulate high levels of flavanone glycosides, like naringin.
• Petunia redirects naringenin towards flavonol glycosides and anthocyanins.

Purpose of the Study:

• To investigate if petunia can perform naringenin glucosylation.
• To characterize the properties of petunia's flavanone glucosylating enzyme.

Main Methods:

• Partial purification of flavanone-7-O-glucosyltransferase (7GT) activity from petunia leaf tissue.
• Enzyme assays using various flavonoid substrates and inhibitors.
• Comparison of petunia 7GT properties with those from grapefruit.

Main Results:

• Petunia leaf tissue exhibits 7GT activity, albeit at lower levels than grapefruit.
• Partially purified petunia 7GT showed activity towards flavanone, flavonol, and flavone substrates.
• Petunia 7GT was significantly more sensitive to UDP inhibition compared to grapefruit 7GT.

Conclusions:

• Petunia possesses flavanone-7-O-glucosyltransferase (7GT) activity capable of naringenin glucosylation.
• Biochemical differences in 7GT enzymes may contribute to distinct flavonoid profiles in petunia and citrus.
• Enzyme properties, such as UDP inhibition sensitivity, play a role in regulating flavonoid accumulation.