TY - JOUR

T1 - Highly phosphorylated functionalized rice starch produced by transgenic rice expressing the potato GWD1 gene

AU - Chen, Yaling

AU - Sun, Xiao-Feng

AU - Zhou, Xin

AU - Hebelstrup, Kim Henrik

AU - Blennow, Andreas

AU - Bao, Jinsong

PY - 2017

Y1 - 2017

N2 - Starch phosphorylation occurs naturally during starch metabolism in the plant and is catalysed by glucan water dikinases (GWD1) and phosphoglucan water dikinase/glucan water dikinase 3 (PWD/GWD3). We generated six stable individual transgenic lines by over-expressing the potato GWD1 in rice. Transgenic rice grain starch had 9-fold higher 6-phospho (6-P) monoesters and double amounts of 3-phospho (3-P) monoesters, respectively, compared to control grain. The shape and topography of the transgenic starch granules were moderately altered including surface pores and less well defined edges. The gelatinization temperatures of both rice flour and extracted starch were significantly lower than those of the control and hence negatively correlated with the starch phosphate content. The 6-P content was positively correlated with amylose content and relatively long amylopectin chains with DP25-36, and the 3-P content was positively correlated with short chains of DP6-12. The starch pasting temperature, peak viscosity and the breakdown were lower but the setback was higher for transgenic rice flour. The 6-P content was negatively correlated with texture adhesiveness but positively correlated with the cohesiveness of rice flour gels. Our data demonstrate a way forward to employ a starch bioengineering approach for clean modification of starch, opening up completely new applications for rice starch.

AB - Starch phosphorylation occurs naturally during starch metabolism in the plant and is catalysed by glucan water dikinases (GWD1) and phosphoglucan water dikinase/glucan water dikinase 3 (PWD/GWD3). We generated six stable individual transgenic lines by over-expressing the potato GWD1 in rice. Transgenic rice grain starch had 9-fold higher 6-phospho (6-P) monoesters and double amounts of 3-phospho (3-P) monoesters, respectively, compared to control grain. The shape and topography of the transgenic starch granules were moderately altered including surface pores and less well defined edges. The gelatinization temperatures of both rice flour and extracted starch were significantly lower than those of the control and hence negatively correlated with the starch phosphate content. The 6-P content was positively correlated with amylose content and relatively long amylopectin chains with DP25-36, and the 3-P content was positively correlated with short chains of DP6-12. The starch pasting temperature, peak viscosity and the breakdown were lower but the setback was higher for transgenic rice flour. The 6-P content was negatively correlated with texture adhesiveness but positively correlated with the cohesiveness of rice flour gels. Our data demonstrate a way forward to employ a starch bioengineering approach for clean modification of starch, opening up completely new applications for rice starch.

KW - Journal Article

U2 - 10.1038/s41598-017-03637-5

DO - 10.1038/s41598-017-03637-5

M3 - Journal article

C2 - 28611462

VL - 7

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

IS - 1

M1 - 3339

ER -