Functional analysis of genes potentially associated with resistance to the basidiomycete Moniliophthora perniciosa in tomato (Solanum lycopersicum) cv. 'Micro-Tom'

Abstract

"Witches' Broom" is a major disease of cacao, limiting cacao production in South America. The basidiomycete Moniliophthora perniciosa, the causal agent, presents a hemibiotrophic lifestyle with a peculiar, extensive biotrophic phase, promoting typical symptoms of hypertrophic growth and proliferation of infected shoots. The tomato (Solanum lycopersicum) cv. 'Micro-Tom' (MT) is a suitable genetic model to study the pathogenic interaction with M. perniciosa S-biotype, exhibiting typical symptoms of the infection, besides the tomato intrinsic characteristics, such as availability of an optimized genetic transformation protocol, transposing difficulties in cacao analysis. The RNA-seq analysis of interaction of the S-biotype x MT interaction enabled the identification of defense response mechanisms to constrain the colonization by M. perniciosa. Nevertheless, the lack of information related to infection by M. perniciosa makes fundamental the implementation of a platform for gene functional analysis, confirming the activated mechanisms to search for pathogen resistance. Furthermore, the comparison of both compatible (S-biotype) or incompatible (C-biotype) interactions with MT may indicate which are the key-factors associated with fungal colonization. Thus, this work proposes a functional analysis of genes associated with defense mechanisms, resistance, containment of fungal penetration and phosphate starvation during S-biotype or C-biotype infection using MT as a model system. The first step consists in the comparison of gene expression during infection by both C-biotype contrasting isolates and one S-biotype isolate via RNA-seq. At the second step, genes identified in RNA-seq analysis from the S-biotype M. perniciosa x MT interaction and the genes identified in the first step of this work will be overexpressed and/or silenced in MT. The knowledge of the molecular mechanisms of defense in MT will be essential to the understanding of the pathosystem and the establishment of control strategies for the "Witches' Broom Disease". (AU)