Characterization of Carotenoid-protein Complexes and Gene Expression Analysis Associated with Carotenoid Sequestration in Pigmented Cassava (Manihot Esculenta Crantz) Storage Root
Luiz Joaquim Castelo Branco Carvalho*, 1, John Lippolis2, Songbi Chen3, Claudia Regina Batista de Souza4, Eduardo A Vieira5, James V Anderson6
1 EMBRAPA Genetic Resources and Biotechnology, Brazil
2 USDA-ARS, National Animal Disease Center, Ames-AI, USA
3 CATAS Tropical Crops Genetic Resources Institute, Dangsou, China
4 Department of Genetics – UFPA, Brazil
5 EMBRAPA Cerrados, Brazil
6 USDA-ARS, Sunflower and Plant Biology Research Unit, Fargo, ND, USA
Carotenoid-protein complex (CPC) was isolated from chromoplast-enriched suspensions of cassava storage root (CSR) using size exclusion chromatography and characterized. Peptide sequences (LC_MS/MS spectrum) obtained from CPC and their corresponding proteins were obtained using publically available databases. Small Heat Shock Proteins (sHSPs) were the most abundant proteins identified in the CPC. Western blot analysis showed that Fribrillin and Or-protein were present in chromoplast-enriched suspensions of yellow root but not in the complex or white root. Results from qRT-PCR helped identify an isoform of HSP21 possessing four single point mutations in the intense yellow CSR that may be responsible for increased sequestration of b-carotene.
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