IJMS, Vol. 18, Pages 2398: Identification, Expression, and Functional Analysis of the Fructokinase Gene Family in Cassava

IJMS, Vol. 18, Pages 2398: Identification, Expression, and Functional Analysis of the Fructokinase Gene Family in Cassava

International Journal of Molecular Sciences doi: 10.3390/ijms18112398

Authors: Yuan Yao Meng-Ting Geng Xiao-Hui Wu Chong Sun Yun-Lin Wang Xia Chen Lu Shang Xiao-Hua Lu Zhan Li Rui-Mei Li Shao-Ping Fu Rui-Jun Duan Jiao Liu Xin-Wen Hu Jian-Chun Guo

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 (MeFRK1–7) were identified, and MeFRK1–6 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.

from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2yv8fu8
via IFTTT