Evaluating the effect and effectiveness of different constructs with a conserved sequence for silencing of Coffea canephora N-methyltransferases.

Caffeine biosynthesis involves sequential methylation
of the purine ring by the transfer of methyl group from the
methyl donor S-adenosyl methionine. Genes that code for the
individual methyl transferase have a high degree of sequence
homology. To achieve decaffeination by genetic engineering of
coffee, the effect and efficiency of different post-transcriptional
gene silencing (PTGS) constructs were evaluated. Sense, antisense
and invert repeat constructs were developed using a
339 bp fragment from the conserved region of the coffee Nmethyltransferase
genes involved in caffeine biosynthesis.