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 upregulated 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.

Constitutive Expression of <i>VvAATP</i> Increases Starch Content in Transgenic <i>Arabidopsis</i>

“…These results suggested that constitutive expression of VvAATP enhanced the starch biosynthesis due to the increased ATP supply into amyloplasts, which further increased the production of precursors (ADPG and G-1-P) and the expression of starch biosynthesis related genes ( Figure 6). The higher level of starch content is related to the increased expression of starch biosynthesis genes [5,[31][32][33][34]. Starch synthase can be grouped into five types, granule-bound starch synthase (GBSS) and four types of soluble starch synthases (SSS): SSS I, SSS II, SSS III and SSS IV [5,6,35].…”

Overexpression of GmSnRK1, a soybean sucrose non-fermenting-1 related protein kinase 1 gene, results in directional alteration of carbohydrate metabolism in transgenic Arabidopsis

“…Overexpression of NtTrxF led to a striking increase of starch accumulation in the leaves of tobacco [1]. The StTrxF/SlTrxF-expressing Arabidopsis plants had higher starch content [8,9]. Wang et al [10][11][12] cloned the SlAATP/StAATP/GmAATP gene from tomato/potato/soybean and found that the transgenic Arabidopsis plants exhibited higher starch content.…”