Resumen de Over-expression of (1,3;1,4)-β-D-glucanase isoenzyme EII gene results in decreased (1,3;1,4)-β-D-glucan content and increased starch level in barley grains
Ning Han, Chenglong Na, Yuqiong Chai, Jianchu Chen, Zhongbo Zhang, Bin Bai, Hongwu Bian, Yulong Zhang, Muyuan Zhu
High content of (1,3;1,4)-?-d-glucan in barley grains is regarded as an undesirable factor affecting malting potential, brewing yield and feed utilization. Production of thermostable bacterial (1,3;1,4)-?-glucanase in transgenic barley grain or supplementation of exogenous bacterial (1,3;1,4)-?-glucanase has been used to improve malt and feed quality. The aim of the present study was to investigate the effect of over-expression of an endogenous (1,3;1,4)-?-glucanase on ?-glucan content and grain composition in barley. RESULTS A construct containing full-length HvGlb2 cDNA encoding barley (1,3;1,4)-?-glucanase isoenzyme EII under the control of a promoter of barley D-Hordein gene Hor3-1 was introduced into barley cultivar Golden Promise via Agrobacterium-mediated transformation, and transgenic plants were regenerated after hygromycin selection. The T2 generation of proHor3:HvGlb2 transgenic lines showed increased activity of (1,3;1,4)-?-glucanase in grains. Total ?-glucan content was reduced by more than 95.73% in transgenic grains compared with the wild-type control. Meanwhile, over-expression of (1,3;1,4)-?-glucanase led to an increase in 1000-grain weight, which might be due to elevated amounts of starch in the grain. CONCLUSION Manipulating the expression of (1,3;1,4)-?-glucanase EII can control the ?-glucan content in grain with no apparent harmful effects on grain quality of transgenic plants. ? 2016 Society of Chemical Industry
