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Increased antioxidant capacity in tomato by ectopic expression of the strawberry D ‐ galacturonate reductase gene
Author(s) -
Amaya Iraida,
Osorio Sonia,
MartinezFerri Elsa,
LimaSilva Viviana,
Doblas Veronica G.,
FernándezMuñoz Rafael,
Fernie Alisdair R.,
Botella Miguel A.,
Valpuesta Victoriano
Publication year - 2015
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201400279
Subject(s) - ascorbic acid , genetically modified tomato , transgene , vitamin c , antioxidant , fructose , reductase , biochemistry , genetically modified rice , ectopic expression , biology , genetically modified crops , gene , food science , enzyme
Abstract Increasing L ‐ascorbic acid (AsA, vitamin C) content in fruits is a common goal in current breeding programs due to its beneficial effect on human health. Attempts to increase AsA content by genetic engineering have resulted in variable success likely due to AsA's complex regulation. Here, we report the effect of ectopically expressing in tomato the D ‐galacturonate reductase (FaGalUR) gene from strawberry, involved in AsA biosynthesis, either under the control of the constitutive 35S or the tomato fruit‐specific polygalucturonase ( PG ) promoters. Although transgenic lines showed a moderate increase on AsA content, complex changes in metabolites were found in transgenic fruits. Metabolomic analyses of ripe fruits identified a decrease in citrate, glutamate, asparagine, glucose, and fructose, accompanied by an increase of sucrose, galactinol, and chlorogenic acid. Significant metabolic changes also occurred in leaves of 35S‐FaGalUR lines, which showed higher non‐photochemical fluorescence quenching (NPQ), indicative of a higher constitutive photo‐protective capacity. Overall, overexpression of FaGalUR increased total antioxidant capacity in fruits and the results suggest a tight control of AsA content, probably linked to a complex regulation of cellular redox state and metabolic adjustment.