CBN-V Video Archives - S5-08
Opaque-2-like Transcriptional Regulatory Gene Mechanism is Present in Cassava Storage Roots

de Souza C.R.B., E.R.P. de Almeida, L.J.C.B. Carvalho and E.S. Gander

EMBRAPA-Genetic Resources and Biotechnology, CP 02372, CEP 70770-900 Sain Parque Rural, Brazilia, Brazil carvalho@cenargen.embrapa.br

        The central cylinder of the storage root (SR) of cassava comprises parenchyma cells packed with starch granule and vessels. Storage proteins are usually not accumulated in this organ, mainly because it is not a propagation organ like most tubers in other plants where starch and proteins are accumulated concomitantly during the organ development. The Opaque-2 is a bZIP transcriptional regulatory protein that interacts with the ACGT core element in gene promoters to regulate the level of transcription of genes in endosperm. To test the hypothesis that this transcriptional regulatory mechanism would be present in regulating genes in the storage process of parenchyma cells in the SR of cassava, we used the compartmentalization tissue model described in an accompanying paper, together with Opaque-2 gene sequence identification, Opaque-2 like protein detection in SR protein extract with Opaque-2 specific Ab and specific DNA fragment recognition by protein extracted from SR. Results indicated that the Opaque-2 specific Ab recognized two proteins of 30 kDa and 45kDa molecular weight in SR protein crude extract, and that the 45 kDa protein recognizes the promoter of the gene be2S1 from Brazil nut. Isolation and cloning of the gene corresponding to this potential regulatory protein is under way.

This research supported by National Biotechnology Program (EMBRAPA), and Brazilian Conselho Nacional de Desenvolvimento Científco e Tecnológico (CNPq)

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