L-Ascorbic Acid: A Multifunctional Molecule Supporting Plant Growth and Development

Table 1

Approaches to increase ascorbic acid content through increasing ascorbate biosynthesis.

Species	Enzyme	Tissue	Gene source	Fold increase in Asc	Comments	Reference
Tobacco	L-Galactose dehydrogenase	Leaves	Arabidopsis	No change	Antisense suppression resulted in lower Asc	[37]
Tobacco	GDP-L-galactose phosphorylase	Leaves	Kiwifruit	3	Transient overexpression by agroinfection	[29]
Arabidopsis	GDP-L-galactose phosphorylase	Leaves	Kiwifruit	4	Stable transformant	[29]
Tobacco	GDP- L-galactose phosphorylase and GDP-mannose-3′,5′-epimerase	Leaves	Kiwifruit	7	Transient overexpression by agroinfection	[29]
Arabidopsis	D-Galacturonic acid reductase	Leaves	Strawberry	2 to 3	Enzyme is from the D-galacturonate pathway	[35]
Tobacco	L-Gulono-1,4-lactone oxidase	Leaves	Rat	7	No clear evidence that the animal Asc biosynthetic pathway exists in plants	[38]
Lettuce	L-gulono-1,4-lactone oxidase	Leaves	Rat	4 to 7	No clear evidence that the animal Asc biosynthetic pathway exists in plants	[38]
Arabidopsis	myo-inositol oxygenase	Leaves	Arabidopsis	2 to 3	myo-inositol/D-glucuronate pathway	[39]