Constitutive Expression of &amp;lt;i&amp;gt;VvAATP&amp;lt;/i&amp;gt; Increases Starch Content in Transgenic &amp;lt;i&amp;gt;Arabidopsis&amp;lt;/i&amp;gt;

Feibing Wang

doi:10.11648/j.bmb.20170206.15

Abstract

A plastidic ATP/ADP transporter (AATP) plays a crucial role in importing ATP from the cytosol into plastids, leading to the increase the ATP supply to facilitate anabolic synthesis in heterotrophic plastids of dicotyledonous plants. The regulatory role of the grapevine VvAATP gene in increasing starch accumulation has not been investigated. In this study, the VvAATP gene was successfully isolated from grapevine and transformed into Arabidopsis. Constitutive expression of VvAATP significantly increased starch accumulation in transgenic Arabidopsis plants. Real-time quantitative PCR analysis showed that constitutive expression of VvAATP up-regulated the expression of the genes related to starch biosynthesis pathway, including phosphoglucomutase, ADP-glucose pyrophosphorylase (AGPase), granule-bound starch synthase (GBSS), soluble starch synthase (SSS) and starch branching enzyme (SBE) genes, in transgenic Arabidopsis plants. Meanwhile, enzymatic analyses indicated that the major enzymes (AGPase, GBSS, SSS and SBE) involved in the starch biosynthesis exhibited higher activities in the transgenic plants compared to the wild-type (WT). These results indicate that VvAATP may improve starch content of Arabidopsis by up-regulating the expression of the related genes and increasing the activities of the major enzymes invovled in starch biosynthesis. All these findings suggest that the VvAATP gene may be applied for increasing starch accumulation of plants in the future.

Highlights

Biofuel, which can decrease environmental damage by reducing the extraction and use of fossil fuels, is more and more important with the society’s development
The VvAATP gene was cloned by reverse transcription PCR (RT-PCR)
The consumption of glucose-1-phosphate (G-1-P) in the ADP-glucose pyrophosphorylase (AGPase) reaction required the accelerated conversion of glucose-6-phosphate (G-6-P) to G-1-P, which was catalyzed by phosphoglucomutase (PGM) [30], and the transcription level of AtPGM was increased in the transgenic plants (Figure 4)

Summary

Introduction

Biofuel, which can decrease environmental damage by reducing the extraction and use of fossil fuels, is more and more important with the society’s development. It is vital to know how carbohydrates are metabolized in plants, which could be of great help in the development of crops by means of enhancing starch synthesis, and in the improvement of biofuel production efficiency [1]. ATP is an indispensable participant in the AGPase reaction, which catalyzes the formation of ADP-glucose (ADPG) and is considered as a rate-limiting enzyme in starch biosynthesis [7]. The mitochondrial AAC is a dimer, and each monomer contains 6 transmembrane helices [9] Another type of adenylate carrier protein is the plastidic ATP/ADP transporter protein (AATP), which was discovered in spinach chloroplasts. The main function of AATP is involved in providing the plastid stroma with cytosolic ATP, to further participate in anabolic processes such as starch and fatty acid synthesis [13]

Methods

Results

Conclusion