Research note: Activity of granule-bound starch synthase is an important determinant of amylose content in rice endosperm
Umemoto, T.; Terashima, K.
Functional Plant Biology Fpb 29(9): 1121-1124
2002
ISSN/ISBN: 1445-4416 PMID: 32689564 Accession: 070553763
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.