Next Article in Journal
In Situ Synthesis of Silver Nanoparticles in a Hydrogel of Carboxymethyl Cellulose with Phthalated-Cashew Gum as a Promising Antibacterial and Healing Agent
Previous Article in Journal
The Complete Mitogenome of the Wood-Feeding Cockroach Cryptocercus meridianus (Blattodea: Cryptocercidae) and Its Phylogenetic Relationship among Cockroach Families
Article Menu
Issue 11 (November) cover image

Export Article

Open AccessArticle
Int. J. Mol. Sci. 2017, 18(11), 2398;

Identification, Expression, and Functional Analysis of the Fructokinase Gene Family in Cassava

Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
College of Agriculture, Hainan University, Haikou 570228, China
Prisys Biotechnologies Company Limited, Shanghai 201203, China
College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing 163319, China
These authors contributed equally to this work.
Authors to whom correspondence should be addressed.
Received: 27 September 2017 / Revised: 6 November 2017 / Accepted: 7 November 2017 / Published: 12 November 2017
(This article belongs to the Section Biochemistry)
Full-Text   |   PDF [6576 KB, uploaded 12 November 2017]   |  


Fructokinase (FRK) proteins play important roles in catalyzing fructose phosphorylation and participate in the carbohydrate metabolism of storage organs in plants. To investigate the roles of FRKs in cassava tuber root development, seven FRK genes (MeFRK17) were identified, and MeFRK16 were isolated. Phylogenetic analysis revealed that the MeFRK family genes can be divided into α (MeFRK 1, 2, 6, 7) and β (MeFRK 3, 4, 5) groups. All the MeFRK proteins have typical conserved regions and substrate binding residues similar to those of the FRKs. The overall predicted three-dimensional structures of MeFRK1–6 were similar, folding into a catalytic domain and a β-sheet ‘‘lid” region, forming a substrate binding cleft, which contains many residues involved in the binding to fructose. The gene and the predicted three-dimensional structures of MeFRK3 and MeFRK4 were the most similar. MeFRK1–6 displayed different expression patterns across different tissues, including leaves, stems, tuber roots, flowers, and fruits. In tuber roots, the expressions of MeFRK3 and MeFRK4 were much higher compared to those of the other genes. Notably, the expression of MeFRK3 and MeFRK4 as well as the enzymatic activity of FRK were higher at the initial and early expanding tuber stages and were lower at the later expanding and mature tuber stages. The FRK activity of MeFRK3 and MeFRK4 was identified by the functional complementation of triple mutant yeast cells that were unable to phosphorylate either glucose or fructose. The gene expression and enzymatic activity of MeFRK3 and MeFRK4 suggest that they might be the main enzymes in fructose phosphorylation for regulating the formation of tuber roots and starch accumulation at the tuber root initial and expanding stages. View Full-Text
Keywords: cassava; fructokinase; gene expression; yeast complementation; enzyme activities cassava; fructokinase; gene expression; yeast complementation; enzyme activities

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Yao, Y.; Geng, M.-T.; Wu, X.-H.; Sun, C.; Wang, Y.-L.; Chen, X.; Shang, L.; Lu, X.-H.; Li, Z.; Li, R.-M.; Fu, S.-P.; Duan, R.-J.; Liu, J.; Hu, X.-W.; Guo, J.-C. Identification, Expression, and Functional Analysis of the Fructokinase Gene Family in Cassava. Int. J. Mol. Sci. 2017, 18, 2398.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Int. J. Mol. Sci. EISSN 1422-0067 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top