Research note: Activity of granule-bound starch synthase is an important determinant of amylose content in rice endosperm
Takayuki Umemoto and Kazuo Terashima
Functional Plant Biology
29(9) 1121 - 1124
Published: 22 August 2002
Effects of temperature on amylose synthesis in rice endosperm were investigated using 13 cultivars known to differ in amylose contents in endosperm. Both amylose content and granule-bound starch synthase (GBSS) activity was increased when endosperms were developed under lower temperature in low- and medium-amylose cultivars, while this was not the case for high-amylose cultivars. Amylose content in high-amylose cultivars was stable under different temperature, with varying GBSS activity. A nearly linear correlation between GBSS activity and amylose content was observed as far as activity levels about 250 nmol min-1 g-1 DW. These results suggest that GBSS activity is an important determinant of amylose content in endosperm of low- and medium-amylose cultivars, while factors other than the enzyme activity limit amylose synthesis in the high-amylose cultivars.
Full text doi:10.1071/PP01145
© CSIRO 2002