Abstract
The purpose of this study is to reveal the genetic mechanism of the variation of amylose content among different semi waxy or glutinous japonica rice in the background of Wxmp gene. Sixty-four semi waxy lines derived from the hybrid progenies of Wujing 13 and Milky Princess (Kantou 194) with polymorphism in soluble starch synthase gene SSIIa (SSII-3) and SSIIIa (SSIII-2) but no polymorphism in other starch synthase related genes were used as test materials. The genotypes of SSIIa and SSIIIa allele were identified by molecular markers, and the allelic effects of SSIIa and SSIIIa gene on amylose content (AC), gel consistency (GC), gelatinization temperature (GT) and rapid visco analyzer (RVA) profile characteristics were analyzed. The significant effects of SSIIa and SSIIIa alleles and the interactive effects between two genes on AC, GT, GC and RVA profile characteristics were found. The SSIIa and SSIIIa alleles from Wujing13 shown positive effects on AC with an average increase of 1.87 and 1.23% in 2 years respectively. There was no significant effect on GT for SSIIa or SSIIIa allele but remarkable influence on GT when the co-existence of the two genes. The genotype SSIIampSSIIIamp shown 1.34 °C higher GT than genotype SSIIawjSSIIIawj (mp and wj indicated that the gene was derived from Milky Princess and Wujing 13 respectively, the same as in the below). Different genes and alleles resulted in significant different GC. The genetic effect of SSIIawj and SSIIIamp on GC was 8.74 and 9.62 mm respectively. The GC of SSIIawjSSIIIamp was 10.64 and 16.95 mm higher than that of SSIIampSSIIIawj and SSIIawjSSIIIawj, respectively. The allele SSIIawj could increase the peak viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV) and breakdown viscosity (BDV), while decrease the consistency viscosity (CSV) and setback viscosity (SBV). However for the allele SSIIIawj the opposite was true. The genotype SSIIawjSSIIIamp had the largest PKV, HPV and CPV, the genotype SSIIawjSSIIIawj had the largest BDV and CSV, but the genotype SSIIawjSSIIIamp had the least SBV. According to the comprehensive effect of each trait, the genotype SSIIawjSSIIIamp was the best. The allelic variation and interaction effect of SSIIa and SSIIIa genes have important reference value for improving cooking and eating quality of semi waxy japonica rice.
Modification of Starch Composition Using RNAi Targeting Soluble Starch Synthase I in Japonica Rice
