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Analise In silico e in vivo da via de isoprenoides em café

Tiski I., Perreira L.F.P., Pot D., Marraccini P., Vieira L.G.E.. 2007. In : EMBRAPA. 5° Simposio de Pesquisa dos Cafés do Brasil, Aguas de lindoia, Brasil, May 7-11, 2007. s.l. : s.n., 4 p.. Simposio de Pesquisa dos Cafés do Brasil. 5, 2007-05-07/2007-05-11, Aguas de Lindoia (Brésil).

The diterpenes khaweol and cafestol, which are present in the coffee lipid fraction, are originated from the isoprenoid pathway. Despite their diversity in functions and structures, all isoprenoids derive from the common-five carbon building unit isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). In higher plants, there are two independent pathways located in the cytosol (mevalonic acid or MVA pathway) and in the plastids (methylerythritol phosphate - MEP pathway). Through the data mining of the Brazilian Coffee Genome Project we studied the genes that code for the enzymes 3-hydroxy-3-methyglutaryl-CoA reductase (HMGR) and mevalonate diphosphate decarboxylase (MPDC) for the MVA pathway, and 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) and isopentenyl diphosphate synthase (IDS) for the MEP pathway. The search for HMGR resulted in 13 ESTs that originated three incomplete contigs, forming two isoforms. For MPDC 7 ESTs formed only one isoform, differently in A. thaliana that has two isoforms. The search for the genes in the MEP pathway resulted in 22 ESTs for DXR and 47 ESTs for IDS. In each case only one contig was formed, similar to found in A. thaliana as well. Southern blots of genes HMGR and DXR demonstrated the presence two isoforms for HMGR and one for DXR. Northern blot analysis detected transcripts of DXR at the beginning of the perisperm development and at the late stages of endosperm and pulp development. Transcripts of the isoform HMGR2 were detected in pulp, perisperm and endosperm, in all the stages of development of the fruit. On the other hand, HMGRI transcripts were observed only in pulp and initial stage of the development of the perisperm and endosperm.

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