Differential expression of genes between storage roots of sweetpotato cultivars jewel and white jewel

Document Type

Article

Publication Date

1-1-2006

Abstract

'White Jewel' is a yellow-and-orange fleshed spontaneous mutant of the orange-flesh sweetpotato [Ipomoea batatas (L.) Lam.] cultivar Jewel. Mutations in storage root flesh color, and other traits are common in sweetpotato. The orange flesh color of sweetpotato is due to β-carotene stored in chromoplasts of root cells. β-carotene is important because of its role in human health. In an effort to elucidate biosynthesis and storage of β-carotene in sweetpotato roots, microarray analysis was used to investigate genes differentially expressed between 'White Jewel' and 'Jewel' storage roots. β-carotene content calculated from a* color values of 'Jewel' and 'White Jewel' were 20.66 mg/100 g fresh weight (FW) and 1.68 mg/100 g FW, respectively. Isopentenyl diphosphate isomerase (IPI) was down-regulated in 'White Jewel', but farnesyl-diphosphate synthase (FPPS), geranylgeranyl diphosphate synthase (GGPS), and lycopene β-cyclase (LCY-b) were not differentially expressed. Several genes associated with chloroplasts were differentially expressed, indicating probable differences in chromoplast development of 'White Jewel' and 'Jewel'. Sucrose Synthase was down-regulated in 'White Jewel' and fructose and glucose levels in 'White Jewel' were lower than in 'Jewel' while sucrose levels were higher in 'White Jewel'. No differences were observed between dry weight or alcohol insoluble solids of the two cultivars. This study represents the first effort to elucidate β-carotene synthesis and storage in sweetpotato through large-scale gene expression analysis.

Publication Source (Journal or Book title)

Journal of the American Society for Horticultural Science

First Page

798

Last Page

805

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