Phytoparasitic nematodes are responsible for major losses in various crops totalling up to 118 billion dollars a year. In terms of economic impact, root lesion nematodes (RLN), Pratylenchus spp. are in 3rd place, which is directly related to the number of host plants, more than 400 plant species (important agricultural crops, ornamentals, and fruit trees, including nuts). Surveys carried out in Portugal have revealed the presence of some Pratylenchus species associated with important crops. Recently, four NLR species were isolated and identified from potato root samples collected in the main potato producing regions in Portugal. The most abundant species was Pratylenchus penetrans, followed by P. neglectus, P. crenatus and P. thornei, the latter being found for the first time associated with this crop in Portugal. In addition to these NLR species, a new species of Pratylenchus, associated with severe damage to flower bulb production (e.g. Amaryllis), has been detected in several greenhouses in Portugal, which reinforces the scale of the threat these species pose to agriculture and floriculture. Resistance to Pratylenchus spp. is very limited, as only a few loci have been linked to resistance/tolerance to some NLR species.Control strategies using chemical compounds are limited by current legislation.Most nematodicides are non-specific, highly toxic, and pose a strong threat to the soil ecosystem, drinking water, as well as human health.Currently, one of the most relevant areas of research is the identification of pathogen genes related to metabolism and parasitism, in which their silencing through RNA interference (RNAi) promotes lethal effects or inhibits their development.Some of the promising results in the control of phytoparasitic pathogens through gene silencing via RNAi include bacteria, fungi, oomycetes, insects and nematodes, mainly the root-knot nematode (Meloidogyne spp.) and the cyst nematode (Globodera and Heterodera spp.).Although gene silencing using RNAi technology has already been demonstrated in some Pratylenchus species, only a few genes (e.g. pat-10, unc-87, Pv010 and eng-1) have been tested, which reflects the need for more extensive studies in relation to this very important group of phytoparasites. The main aim of this project is to identify genes encoding proteins in P. penetrans that can be used as new targets for the development of more specific and efficient control strategies.Global transcriptomes involving the parasite-host are an excellent tool for providing an integrated view of the molecular dialogue established between the pathogen and the host and, ultimately, for identifying the main molecular pathways and individual genes involved in this interaction.Our starting material consists of different large-scale transcriptomics datasets generated “in house” (“paired-end sequencing mRNA-seq”, Illumina) for P. penetrans: 1) from the nematode, and 2) from soya plants infected with this species, which will be used as a basis for selecting new target genes.In addition, new transcriptome datasets will be obtained from the infection of potato plants by P. penetrans.In this context, the project involves the implementation of biotechnological approaches to plant breeding, using Illumina mRNA-seq data to identify new target genes and RNAi silencing technology to study their action as potential nematodicides. The strategy to be used throughout this project includes the study of the expression levels and localisation of the genes to be silenced in the nematode, and the production of siRNA and dsRNA fragments for silencing these genes via in vitro assays, and later via the plant, assessing their efficiency in interrupting the nematode’s development or even lethality.Another important aspect of the PratyTech proposal is knowing the nematode’s gene expression profile or even lethality.Another important aspect of the PratyTech proposal is to understand the host’s gene expression profile and the cellular changes that occur after infection of the potato plant with P. penetrans, which could provide important information on the molecular mechanisms involved in this economically important crop.In the long term, our goal is to develop alternative and innovative methodologies that will allow us to obtain NLR-resistant crops to be applied to agricultural crops (horticulture, floriculture and orchards) that are important not only in Portugal, but also in other parts of Europe and the world where P. penetrans has a relevant economic impact.