PECTOWARS will pioneer a radically new perspective on plant diseases caused by fungi, a fundamental aspect of plant biology and food safety. The plant cell wall (CW) is the foremost interface where interactions between plants and fungi take place. Fungal pathogens use CW degrading enzymes to digest plant CWs, gaining access to host tissues and causing extensive devastation. The plant pectin methylesterases (PMEs) emerge as critical factors for the outcome of plant-fungus interaction. However, the current knowledge about the molecular mechanisms regulating the activity of these enzymes is limited and the exact role of PME activity and of genes underlying its regulation is poorly understood. With PECTOWARS we wish to generate a complete picture of the contribution of plant PMEs in plant immunity. We aim to understand the dynamic orchestration of genes regulating PME activity in Arabidopsis-Botrytis pathosystem using reverse genetics, fluorescent protein tagging, and biochemical approaches. I will make use of my extensive experience on the topic to develop a workflow focused on deciphering the contribution of these proteins to CW reinforcement, Methanol and Oligogalacturonide release during infection by glycomic and chromatography/mass spectrometry platforms. Through a careful combination of multidisciplinary approaches, we will provide ground-breaking evidences on plant molecular mechanisms contrasting fungal penetration and diffusion. The genetic and biochemical traits identified in the project will provide valuable information useful to develop crop varieties with a durable resistance to necrotrophs.
The project aims to use new analytical tools to reach unexplored targets. The study of both gene expression and cell wall modifications is usually conducted by plant physiologist and pathologist at precise time points during pathogen infection. Monitoring changes in both wall polysaccharides as they occur and at the point of fungal penetration thanks to the probes available by confocal microscopy gives the project an innovative character. The possibility of combining the biochemistry of proteins with the plant physiology associated with plant protection is a strength of the project. The possibility of expressing and crystallizing the different forms of PME17 will certainly lead to a strong gain in terms of knowledge on the role of the pro-region in the regulation of PME activity. The multidisciplinary work plan in will lead to a better knowledge of the complex plant-fungal pathogen interactions in the model plant Arabidopsis thaliana. Our efforts will provide new experimental tools and platforms to analyse, at molecular level, the plant-pathogen interactions.
Recent researches revealed that post-harvest losses of fruit and vegetable are estimated to be 40-50% (1). Due to post-harvest losses more than 30% of harvested fruits will not reach the consumers plate. Fungal pathogens play a key role in those losses, as they cause most of the vegetable and fruit rots and the customers complaints. Development of resistant cultivars represents a major environmentally friendly solution for both breeders and plant pathologists. The molecular dynamics and underlying genes identified in the project in the Arabidopsis thaliana model plant will represent excellent tools to produce crop varieties with a durable resistance to B. cinerea, either by traditional breeding or by genetic engineering. The results foreseen in this proposal will have an impact well beyond the species and pathogen here studied: most likely, analogous molecular mechanisms control PME activity during infection with other necrotrophic pathogens and in other crop species. The availability of new resistant genotypes can reduce the need of fungicides and minimize their impact on the environment, ensuring a high standard of plant yield and food quality resulting in a long-term benefit for citizens, economy and society. Taken together all the research activities of the project address in a most considerable way to food security, sustainable agriculture and bio-economy goals of the tackling social challenge targets.
1. Alkan N, Fortes AM. Insights into molecular and metabolic events associated with fruit response to post-harvest fungal pathogens. Front Plant Sci [Internet]. 20 ottobre 2015 [citato 19 giugno 2019];6. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4612155/