Determination of epigenetic marks of grapevine genes in the early response to Plasmopara viticola: immunity related subtilisin-like proteases as a case study

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Insights into the epigenetic and transcriptional response of grapevine to P. viticola infection

Publication . Azevedo, Vanessa; Figueiredo, Andreia; Alagna, Fiammetta; Malhó, Rui

Downy mildew, caused by the biotrophic oomycete Plasmopara viticola, is one of the most economically significant grapevine diseases worldwide. Current strategies to cope with this threat rely on the massive use of chemical compounds during each cultivation season. The economic costs and negative environmental impact associated with these applications increased the urge to search for alternative strategies for sustainable disease control. Improved knowledge of plant mechanisms able to counteract pathogen infection may allow the development of alternative strategies for plant protection. To confirm the different response to Plasmopara viticola infection evaluated in preliminary studies, a leaf disc assay and an artificial inoculation test on potted plants (in planta assay) were performed on Vitis vinifera crossing hybrids selected from breeding activities for their contrasting level of susceptibility to the pathogen. Results of both experiments reveal a different susceptibility between bunches and leaves to P. viticola infection for most of the genotypes analysed. The genotypes N20/020 and N23/018 were the most contrasting genotypes regarding disease incidence (more susceptible (S) and tolerant (T), respectively) and therefore selected for molecular studies. Epigenetic regulation, in particular DNA methylation, is emerging as a key factor in the context of plant-pathogen interactions, associated with the expression modulation of defense genes. To improve our understanding of the genetic and epigenetic mechanisms underpinning grapevine response to P. viticola, we studied the modulation of both 5-mC methylation and gene expression at 6- and 24-hours post-infection (hpi). Following pathogen infection, we found variations in the 5-mC methylation level and in the gene expression profile. The results indicate a genotype-specific response to pathogen infection. The tolerant genotype (N23/018) at 6 hpi exhibits a lower methylation level compared to the susceptible one (N20/020), and it shows an early modulation (at 6 hpi) of defense and epigenetic-related genes during P. viticola infection. These data suggest that the timing of response is an important mechanism to efficiently counteract the pathogen attack.

2025-01-21Tese de doutoramento

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Fundação para a Ciência e a Tecnologia

Número da atribuição

PD/BD/142909/2018