The production of phenolic metabolites has been optimized in parallel to sugarcane micropropagation in temporary immersion bioreactors (TIBs). Culturing micropropagated plants in 0.4% CO 2 -rich air induced their photosynthetic activity by enhancing the change from a heterotrophic to a photomixotrophic metabolic stage. Under 0.4% CO 2 enrichment, the transcript levels of both phenylalanine ammonia-lyase (PAL EF189195) and ribulose-1,5-biphosphate carboxylase/oxygenase (Rubisco CF576750) increased and were correlated to a 4.6-and 6.3-fold increase in the phenolic levels when plants were multiplied in 20 or 30 g/l sucrose, respectively. A novel application of plant phenolic metabolites as elicitors of resistance to tomato bacterial wilt in the Solanum lycopersicum-Ralstonia solanacearum pathosystem has been identified. The culture media was collected, and the phenolics were sprayed onto tomato plants infected with R. solanacearum, eliciting and/or maintaining an early defense signaling mechanism that resulted in the protection of the plant against the tomato bacterial wilt disease. RT-PCR analyses confirmed that selected genes from defense-related pathways were differentially expressed between plants treated with sugarcane metabolites, non-treated pathogenfree plants, and non-treated plants inoculated with R. solanacearum.

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