Differences in Amylopectin Structure Between Two Rice Varieties in Relation to the Effects of Temperature During Grain-Filling

Abstract

The structure of endosperm amylopectin was compared between two rice varieties, Kinmaze (subspecies japonica) and IR36 (subspecies indica), as well as their waxy mutants, all grown under controlled temperature. The distinct varietal difference in chain length distribution of amylopectin was confirmed by high performance anion‐exchange chromatography equipped with pulsed amperometric detection. Amylopectin from Kinmaze contains more very short chains with degree of polymerization (DP) between 6 and 10 and less chains with DP from 13 to 22 than amylopectin from IR36, while there is little difference in the distribution of longer chains with DP > 24 between the two varieties. Waxy mutation had little effect on chain length distribution of endosperm amylopectin. The temperature during grain‐filling affected the chain length distribution of amylopectin in both varieties in a similar way; grain‐filling at lower temperatures lead to an increased proportion of chains of DP 6—13 and decreased the percentage of chains with DP 20—27 and DP 44—54. However, the temperature‐dependent changes in chain length distribution of amylopectin were within the range of varietal difference between Kinmaze and IR36. These results strongly suggest that factors regulating the varietal difference in patterns of chain length of amylopectin are dissimilar to those causing the temperature effects on amylopectin fine structure in rice endosperm.

Physicochemical Characterization of Selected Rice (Oryza Sativa L.) Genotypes Based on Gel Consistency and Alkali Digestion

“…Moreover, 25≤ DP ≤ 36 is attributed to the long B2 chains while DP ≥ 37 forms the B3 long chains. Rice starch granules with amylopectin enriched with the shorter chains easily disintegrates in alkali solution than starch granules that have longer chains of amylopectin [15].…”

“…Similar classifications have been reported in Thai rice cultivars [21]. Genotypes that were least affected by the alkali solution had a low ADV, which could be attributed to the presence of more long amylopectin chains (B2 and B3) than the short (A and B1) amylopectin chains [15]. The activity of the SSIIa is highest in the low alkali digestion cluster than in other classification.…”

Effects of Variations in Starch Synthase on Starch Properties and Eating Quality of Rice

“…The temperature during grain fi lling clearly affects amylose content of rice with the Wx b allele, but not that of rice with the Wx a allele (Asaoka et al, 1984;Hirano and Sano, 1998;Umemoto and Terashima, 2002). Rice grains that mature at a lower temperature have amylopectin rich in short chains (Umemoto et al, 1999;Inouchi et al, 2000), presumably through changes in branching enzyme activities (Jiang et al, 2003). In addition to the higher amylose content due to the Wx a allele, the higher proportion of amylopectin short chains together with the higher protein content of NIL(Wx Overall preference and gloss were scored from -5 to +5 (11 classes), and stickiness and softness from -3 to +3 (7 classes).…”

Starch Properties and Structure of A Wheat Mutant High in Resistant Starch

“…Milled wheat flour was debranched as described by Umemoto et al [35] and the amylopectin chain-length (ACL) distribution profile determined by high performance anion exchange chromatography with pulsed amperometric detection (HPAE-PAD) [36].…”