Physiological and molecular characterization of plants silenced for possible regulatory genes for caffeine biosynthesis

• Grant number: 13/16429-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: October 01, 2013
• End date: March 31, 2015
• Field of knowledge: Agronomical Sciences - Agronomy
• Principal Investigator: Paulo Mazzafera
• Grantee: Ilse Fernanda Ferrari
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Caffeine is one of the products of secondary metabolism economically important to be present naturally in coffee, tea and other plant products consumed by humans. However, according to several studies showing that caffeine could be related to the onset of various diseases, there was the emergence of a promising market for decaffeinated coffee. Currently,removal of caffeine is made by industrial chemical processes, besides being costly, commits compromise the final quality of the drink. Aiming alternatives to this type of decaffeinated coffee, studies were performed inducing chemical mutagenesis in Catuai commercial cultivar of Coffea arabica plants to produce naturally decaffeinated (Mazzafera, unpublished data). Seven plants with low caffeine content were obtained from the screening were performed and calls Decaffito. It was found in these plants expressing low caffeine synthase, the enzyme that converts theobromine to caffeine, however,sequencing the gene indicated no mutation. Besides the low caffeine content, the plants had Decaffito early anthesis, with the flowers still very new, provided by the absence of mucilage released by coleters and that lines and protects the floral meristem. The premature opening facilitates the early flowers cross-pollination leading to the recovery of normal levels of caffeine in the seeds of the next generation, as well as the return to normal flowers. Given the fact that different events so closely linked arises the hypothesis that would be regulated by transcription factors (TF). We proceeded to the sequencing and characterization of cis elements of the promoter region of caffeine synthase, and using bioinformatics, we identified five possible TFs that could control its expression. Analysis of the expression of these genes showed that two of them were scarcely expressed in Decaffito. This project aims to characterize functionally these two FTs in coffee and in model plants (Arabidopsis and Nicotiana). To this purpose, the transformation is made from the two aforementioned model plant, as well as Coffea canephora by RNAi, and subsequent phenotypic characterization.