Physicochemical Characteristics and QTL Mapping Associated with the Lipid Content of High-Lipid Rice

Abstract

This study was conducted to examine the physicochemical characteristics and perform QTL mapping of genetic factors associated with the lipid content of rice. A rice strain with a high lipid content, "P31-2-2-2-B-B", was developed from mutants of "Dongjin" created by T-DNA insertion. The lipid content of "P31-2-2-2-B-B" brown rice was 4.42% whereas that of the donor cultivar "Dongjin" was 2.56%. The total fatty acid content of the high-lipid mutant brown rice was 7.82% and that of "Dongjin" was 3.43%. The unsaturated fatty acid composition of the mutant brown rice was 2.73% oleic acid, 2.74% linoleic acid, and 0.34% linolenic acid. In contrast, the fatty acid composition of the donor cultivar "Dongjin" was 1.30% oleic acid and 0.99% linoleic acid. The percentage of unsaturated fatty acid to total fatty acid in the high-lipid mutant was higher (74.3%) than that of "Dongjin" (66.8%). Continuous frequency distribution and transgressive segregation of the lipid content were observed in the F 3 family (seeds) derived from a cross between the high-lipid mutant "P31-2-2-2-B-B" and a tongil-type cultivar "Samgang". This result implied that the lipid content was a quantitative trait controlled by a polygene. Additionally, the broad sense heritability of lipid content was estimated to be 89.6% based on analysis of the F 3 seeds. A significant QTL, qRLC5, was identified on chromosome 5 with a LOD score of 2.37, and was flanked by 5007 and 5014. Results of the present study should be useful for improving rice nutritional quality through marker-assisted selection.

Analysis of Rice Grain Quality-Associated Quantitative Trait Loci by Using Genetic Mapping

“…Other studies have found QTLs associated with protein and lipid content on chromosomes 5 and 7, respectively. The three QTLs related to protein and lipid content was located at different positions from those reported in previous studies [13] [14]. These differences likely resulted from the difference in genetic stock.…”

Analysis of QTLs Associated with the Rice Quality Related Gene by Double Haploid Populations

“…The QTLs for protein content were detected commonly on chromosomes 3, 6, and 7 [6–8]. Also the QTLs for lipid content were commonly detected on chromosomes 5, 6, and 7 [6–9]. In spite of many results, several new QTLs related to amylose and proteins were detected on chromosomes 11 and 2, respectively.…”

“…Among these loci, qFC-5 on chromosome 5 was the QTL with the largest effect, explaining 12.9% of the phenotypic variance and showing an additive effect of 0.091% [8]. QTL related to rice lipid content (RLC) with 2.37 of LOD score was identified on chromosome 5 from the high lipid mutant line derived from “Dongjin” by T-DNA insertion [9]. …”