title: Phosphomannose isomerase affects the key enzymes of glycolysis and sucrose metabolism in transgenic sugarcane overexpressing themanAgene.
abstract: Sugarcane is one of the most important crops cultivated for the production of sugar and ethanol. In our previous studies, an innovative positive selection system for obtaining transgenic sugarcane, which utilized theE. coli-derivedmanAgene as the selectable marker and mannose as the selective agent, was developed and patented in China. In this paper, the influence of phosphomannose isomerase (PMI) overexpression on the key enzymes of both glycolysis and sucrose metabolism was investigated in transgenic sugarcane through themanAgene. Overexpressed PMI increased hexokinase activity by approximately 24 % compared with non-transgenic control plants, but pyruvate kinase (PK) activity was reduced by approximately 14 %. In comparison with the non-transgenic control plants, the activities of sucrose synthase, sucrose-phosphate synthase, and acid invertase were also modestly affected in the PMI-overexpressing transgenic plants, but no significant differences were observed at the stalk elongation and maturity stages. However, agronomic and technical traits were not affected bymanAgene overexpression in the transgenic sugarcane. In conclusion, PMI overexpression significantly affected the hexokinase and PK activities by catalyzing the reversible interconversion between mannose-6-phosphate and fructose-6-phosphate, which is an intermediate of glycolysis. However, it had no significant effects on sucrose accumulation in sugarcane.
authors: State Key Laboratory of Conservation and Utilization of Subtropical Agri-Biological Resources, Guangxi University, Nanning, 530005 China ; Fujian Agricultural and Forestry University, Fuzhou, 350002 China.
authors: Muqing
authors: M
authors: Zhang
authors: Fujian Agricultural and Forestry University, Fuzhou, 350002 China.
authors: Xiaolei
authors: X
authors: Zhuo
authors: State Key Laboratory of Conservation and Utilization of Subtropical Agri-Biological Resources, Guangxi University, Nanning, 530005 China.
authors: Jihua
authors: J
authors: Wang
authors: Fujian Agricultural and Forestry University, Fuzhou, 350002 China.
authors: Chuanyu
authors: C
authors: Yang
authors: IRREC-IFAS, University of Florida, Fort Pierce, FL 34945 USA.
authors: Charles A
authors: CA
authors: Powell
authors: Fujian Agricultural and Forestry University, Fuzhou, 350002 China.
authors: Rukai
authors: R
authors: Chen
keywords: Glycolysis; Phosphomannose isomerase (PMI); Sucrose accumulation/degradation; Sugarcane (Saccharum officinarum L.); Transgenic plant