Temperature induced changes in the starch components and biosynthetic enzymes of two rice varieties

Abstract

The effects of temperature on starch and amylose accumulation, fine structure of amylopectin and activities of some enzymes related to starch synthesis in developing rice endosperms was examined. Two early indica rice varieties were used, differing in amylose concentration (AC, %), namely Jia 935 (low AC) and Jia 353 (high AC). The results showed that the effects of high temperature on AC and amylopectin fine structure were variety-dependent. High temperature caused a reduction in amylose concentration and an increase in the short chain (CL<22) proportion of amylopectin for Jia 935; while opposite was true for Jia 353. High temperature also reduced and increased the activity of granulebound starch synthase (GBSS) in Jia 935 and in Jia 353, respectively. This suggests that a change in the ratio of amylose/starch due to temperature was attributable to a change in GBSS activity. Moreover, obvious differences between the two rice varieties were detected in the activities of sucrose synthase (SuSy), ADP-glucose pyrophosphorylase (ADPG-Ppase), soluble starch synthase (SSS), starch branching enzyme (SBE), starch de-branching enzyme (SDBE) and starch phosphorylase (SPase) to high temperature. Accumulation rate of amylose was significantly and positively correlated with GBSS for Jia 935, but not for Jia 353. Amylose accumulation was also significantly and positively correlated with the activities of SDBE, SBE, ADPG-Ppase and SuSy for both varieties. The results suggest that the ratio of amylose to starch in rice endosperm is not only related to GBSS, but also affected by the activities of SDBE, SBE, ADPG-Ppase and SuSy.

Activities of Enzymes for Sucrose-Starch Conversion in Developing Endosperm of Rice and Their Association with Grain Filling in Extra-Heavy Panicle Types

“…This result suggests that the difference in temperature conditions would not completely explain the differences in AGPase activity and other grain filling parameters between Nanjing 11 and Akenohoshi. Cheng et al (2005) examined the activities of several enzymes in developing rice endosperm of two cultivars with different amylose contents under different temperature conditions. They revealed in both cultivars that under a high temperature SuSy activity was higher in early developmental stages, whereas the activity became lower in middle to later stages.…”

Impact of Elevated Nighttime Air Temperatures During Kernel Development on Starch Properties of Field‐Grown Rice

“…Lisle et al (2000) did not find any differences in the amylopectin chainlength distribution of three cultivars grown at different daily mean temperatures. Cheng et al (2005) reported opposite effects on the proportion of amylopectin short chains (DP < 22): these chains increased in the low-amylose cultivar but decreased in the high-amylose cultivar. Cheng et al (2005) reported opposite effects on the proportion of amylopectin short chains (DP < 22): these chains increased in the low-amylose cultivar but decreased in the high-amylose cultivar.…”

Expression of granule‐bound starch synthase in developing rice grain

“…10 However, the recent study of Cheng et al 5 indicates that the amylose content in rice grain is not only related to GBSS but also affected by the activities of SBE and SDBE. In the present study, the activities of SBE for Tainung 67 were maintained at relatively high levels prior to 7 DAA, then started to decline thereafter (Fig.…”

“…3 GBSS functions specifically to elongate amylose, whereas a concerted action of SSS, SBE and SDBE produces amylopectin. 5 Rice is consumed principally as a whole grain; therefore, the texture of the whole grain is of primary importance. The content of amylose, which is defined as a ratio to the total amount of starch, is widely considered as one of the major determinants of cooking and eating qualities of rice grain.…”