Molecular tagging of a novel genetic locus linked to accumulation of Lutein – a therapeutic carotenoid in rice grains

Abstract

Lutein is one of the major carotenoids in eye macula and its deficiency is attributed to age-related macular degeneration (AMD) and cataracts. Developing Lutein rich staple food crop will help in supplementing its requirement among rural people through regular diet. The present study was undertaken with a view to tag genetic loci controlling lutein accumulation in rice through Bulked Segregant Analysis (BSA). Estimation of lutein content in the dehusked grains of selected 65 RILs revealed the normal distribution (1.14-285.62 µg/100gm) of lutein accumulation with a significance of p<0.041. Parental polymorphism survey using > 350 genome wide SSR markers detected 30.8% (108 SSR markers) polymorphism between Kavuni and CO 50 rice genotypes. BSA of extreme bulks containing contrasting levels of lutein along with the parents using the genome wide polymorphic SSR markers resulted in the identification of four SSR markers namely RM197 (3.0 Mb), RM204 (3.1 Mb), RM225 (3.4 Mb) and RM19442 (3.7Mb) on chromosome 6 showing clear association with the lutein content. Single-marker linear regression approach using the allelic pattern of all four markers in the region 3.0-3.7Mb showed significant association with lutein content. The regression analysis showed that the SSR markers in the region 3.0-3.7Mb linked QTL accounted for 35.9% of the genetic variation for lutein content.