The basidiomycete Moniliophthora perniciosa is the causal agent of the cacao witches broom disease, one of the main diseases that limit cacao production. With the sequencing of the pathogen and host (Theobroma cacao) genomes, with the consequent identification of putative signaling and defense genes, requires the establishment of a functional analysis platform to demonstrate gene function. Understanding the molecular mechanisms active in the Theobroma cacao x M. perniciosa interaction could enable the development of new approaches for disease control. In this scenario, methods of genetic transformation of cacao are essential, but inherent characteristics of the species limit its in vitro cultivation and the efficiency of genetic transformation. Therefore, the miniature tomato (Solanum lycopersicum)cultivar 'Micro-tom' (MT), considered a genetic model, and the availability of pathogenic S-biotype isolates of M. perniciosa that infects Solaneceae, demonstrated to be a suitable study model for this pathossystem. Thus, expression of cacao genes from the signalling pathway(NPRs/synthesis of salicilate and LRR-RLK receptors) and associated with defense (PR proteins, glucanases and chitinases) identified by RNAseq analysis of the interaction transcriptome T. cacao x M. perniciosa will be overexpressed or silenced by MT genetic transformation. Functional studies will be conducted to confirm function of the selected cacao genes. Further, expression of tomato orthologous genes will be validates in the interaction MT x M. perniciosa pathogenic to cacao (C-biotype; incompatible) and Solanaceae (S-biotype; compatible)by quantitative amplification of reversed transcripts.
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