|CARVALHO, LUIZ - Embrapa Genetic Resources|
|DE ALMEIDA, JULIANA - Embrapa Genetic Resources|
|VIERIA, EDUARDO - Embrapa|
|CHEN, SONGBI - Chinese Academy Of Agricultural Sciences|
|DE SOUZA, CLAUDIA - Universidade Federal Do Parana|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 9/1/2012
Publication Date: 7/1/2013
Citation: Carvalho, L.J., De Almeida, J.D., Anderson, J.V., Vieria, E.A., Chen, S., De Souza, C.R., Fuhrmann, E., Padilha da Silva, J. 2013. Protein content variation in cassava (Manihot esculenta Crantz) storage root associated with carotenoid content. Plant Mutation Reports, Vol. 3, No 1, July 2013. Vienna, Austria. International Atomic Energy Agency, Vienna International Centre, publisher. pp. 25-36. Available: http://www-pub.iaea.org/books/IAEABooks/10598/Plant-Mutation-Reports-Vol-3-No-1-July-2013.
Interpretive Summary: Previous reports on variation of protein content in cassava storage root suggested an association with root pigmentation and secondary growth proceeds. In this report, we confirm that protein content in storage root of cassava was correlated with total carotenoid content. Among the carotenoid-protein complexes identified in storage root of cassava in this study, carotenoid type appears to be associated with specific proteins and protein polymorphisms. Our results further indicate that protein sink capacity parallels accumulation of total carotenoid and ß-carotene content in storage root of different cassava landraces. These results opened up a new avenue of research to improve cassava nutrition quality by improving our understanding of the molecular machinery of accumulating proVit_A carotenoid and protein.
Technical Abstract: Protein content in storage roots of cassava is low but variable and characterization of this variability is lacking. Total buffer extractable proteins (TBEP) content in pigmented cassava landraces varied from 0.9-7.5 (mg/gDWt.) and correlated with total carotenoid content (R2=0.4757). More than 3x TBEP was detected in high compared to low carotenoid roots, corresponding to 55% more proteins in the bulk root tissue. Variable distribution of protein content in root tissue layers was also observed due to tissue age as secondary growth proceeds. Protein polymorphisms showed high protein profile complexity in pigmented compared to non-pigmented roots. SDS_PAGE analysis including an 18 kDa protein in low carotenoid root, 38 and 43 kDa proteins in high carotenoid root, and 23 and 58 kDa proteins in high lycopene root. Protein visualization accessed by 2DE gel analysis of purified chromoplasts varied from 50-143 spots and correlated to total carotenoid (R2=0.8958). ß-carotene and lycopene were the major carotenoid type present in the carotenoid-protein complex, depending on the landrace. Together these results opened up a new avenue of research to improve cassava nutrition quality by improving our understanding of the molecular machinery of accumulating proVit_A carotenoid and protein.