Estudio genómico, transcriptómico y proteómico del proceso de infección del hongo fitopatógeno botrytis cinerea

Résumé

This Doctoral Thesis comprehensively addresses the study of Botrytis cinerea, a fungal pathogen with scientific and economic relevance due to its ability to infect various plant species including numerous commercial crops, focusing on the knowledge of its biology, the infection mechanisms it employs, and the proposal of new agents used for the control of the disease generated by the plant pathogen. Throughout 4 chapters, special emphasis is placed on the application of omics techniques, such as genomics and proteomics, to better understand the molecular mechanisms employed by B. cinerea during its infection cycle and the use of endophytic microorganisms for its biological control. In the first chapter, the genes BcPKS2, BcPKS7 and BcPKS20, responsible for encoding polyketide synthase (PKS) enzymes in B. cinerea, were examined, with an initial focus on the production of botrycinereic acid. However, the generation of knock-out mutants for these genes did not reveal significant changes in growth, sporulation, metabolic activity, pathogenicity compared to the wild-type strain, as well as, in its metabolite production. In the second chapter, the BcNRPS1 cluster of B. cinerea was investigated by targeted mutagenesis. Deletion of these genes showed no significant differences in growth, sporulation and pathogenicity in different hosts and environmental conditions. Response to fungicides was comparable to the wild-type strain, highlighting the complexity of B. cinerea adaptation to chemical interventions. Sensitivity to oxidative stress varied, challenging assumptions about the essentiality of these genes in the adaptive mechanisms of the fungus. In the third chapter, a detailed study of in vitro infection of B. cinerea in white grapes was carried out using proteomic techniques. Complex molecular interactions between pathogen and host were identified, with an increase in the number of proteins identified as the infection progressed. Protein expression patterns changed between early and late stages, revealing adaptive strategies of B. cinerea to overcome host defenses. In the last chapter, the potential of ginger endophytic microorganisms as biocontrol agents against B. cinerea was explored. The isolated bacterial strains showed significant inhibitory capacity, producing secondary metabolites and key enzymes for their antifungal action. Phylogenetic analysis revealed the presence of species known for their biocontrol capacity, highlighting the duality of functions in promoting plant growth. Overall, the thesis provides a deeper understanding of the biology and interaction of B. cinerea, challenging and extending previous knowledge, and suggesting promising prospects for biological control strategies in sustainable agriculture.