StTrxF, a potato plastidic thioredoxin F-type protein gene, is involved in starch accumulation in transgenic Arabidopsis thaliana

Abstract

The plastidic thioredoxin F-type (TrxF) protein plays a key role in plant carbohydrate metabolism. In this work, a gene encoding the TrxF protein, named StTrxF, was successfully isolated from potato and transformed into Arabidopsis thaliana to obtain transgenic plants. Constitutive expression of StTrxF significantly increased the starch accumulation in the transgenic plants. Real-time quantitative polymerase chain reaction analysis showed that constitutive expression of StTrxF up-regulated the expression of the adenosine diphosphate (ADP)-glucose pyrophosphorylase (AGPase) small subunit (AtAGPase-S1 and AtAGPase-S2), AGPase large subunit (AtAGPase-L1 and AtAGPase-L2) and soluble starch synthases (AtSSS I, AtSSS II, AtSSS III and AtSSS IV) genes involved in starch biosynthesis in the transgenic A. thaliana plants. Meanwhile, enzymatic analyses indicated that the major enzymes (AGPase and SSS) involved in the starch biosynthesis exhibited higher activities in the transgenic plants compared to the wild-type. These results suggest that StTrxF may improve the starch content of A. thaliana by up-regulating the expression of the related genes and increasing the activities of the major enzymes involved in starch biosynthesis. The StTrxF gene may be applied for increasing starch accumulation of plants in the future.

Keywords

• Arabidopsis thaliana
• constitutive expression
• potato
• starch content
• StTrxF