Open AccessOverexpression of plastidial thioredoxin f leads to enhanced starch accumulation in tobacco leaves
Author(s) -
SanzBarrio Ruth,
CorralMartinez Patricia,
Ancin Maria,
SeguiSimarro Jose M.,
Farran Inmaculada
Publication year - 2013
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.12052
Subject(s) - starch , biology , photosynthesis , carbohydrate metabolism , biofuel , plastid , thioredoxin , botany , metabolism , carbohydrate , biomass (ecology) , enzyme , biochemistry , chloroplast , food science , gene , microbiology and biotechnology , agronomy
Summary Starch, the most abundant storage carbohydrate in plants, has been a major feedstock for first‐generation biofuels. Growing fuel demands require, however, that the starch yields of energy crops be improved. Leaf starch is synthesised during the day and degraded at night to power nonphotosynthetic metabolism. Redox regulation has been associated with the coordination of the enzymes involved in starch metabolism, but neither the signals nor mechanisms that regulate this metabolism are entirely clear. In this work, the thioredoxin ( T rx) f and m genes , which code for key enzymes in plastid redox regulation, were overexpressed from the plastid genome. Tobacco plants overexpressing T rx f, but not T rx m , showed an increase of up to 700% in leaf starch accumulation, accompanied by an increase in leaf sugars, specific leaf weight ( SLW ), and leaf biomass yield. To test the potential of these plants as a nonfood energy crop, tobacco leaves overexpressing T rx f were subjected to enzymatic hydrolysis, and around a 500% increase in the release of fermentable sugars was recorded. The results show that T rx f is a more effective regulator of photosynthetic carbon metabolism in planta than T rx m. The overexpression of T rx f might therefore provide a means of increasing the carbohydrate content of plants destined for use in biofuel production. It might also provide a means of improving the nutritional properties of staple food crops.