title: Plant-parasitic nematodes: towards understanding molecular players in stress responses.
abstract: BACKGROUND
  Plant-parasitic nematode interactions occur within a vast molecular plant immunity network. Following initial contact with the host plant roots, plant-parasitic nematodes (PPNs) activate basal immune responses. Defence priming involves the release in the apoplast of toxic molecules derived from reactive species or secondary metabolism. In turn, PPNs must overcome the poisonous and stressful environment at the plant-nematode interface. The ability of PPNs to escape this first line of plant immunity is crucial and will determine its virulence.
  
  
  METHODS
  Nematodes trigger crucial regulatory cytoprotective mechanisms, including antioxidant and detoxification pathways. Knowledge of the upstream regulatory components that contribute to both of these pathways in PPNs remains elusive. In this review, we discuss how PPNs probably orchestrate cytoprotection to resist plant immune responses, postulating that it may be derived from ancient molecular mechanisms. The review focuses on two transcription factors, DAF-16 and SKN-1 , which are conserved in the animal kingdom and are central regulators of cell homeostasis and immune function. Both regulate the unfolding protein response and the antioxidant and detoxification pathways. DAF-16 and SKN-1 target a broad spectrum of Caenorhabditis elegans genes coding for numerous protein families present in the secretome of PPNs. Moreover, some regulatory elements of DAF-16 and SKN-1 from C. elegans have already been identified as important genes for PPN infection.
  
  
  CONCLUSIONS
  DAF-16 and SKN-1 genes may play a pivotal role in PPNs during parasitism. In the context of their hub status and mode of regulation, we suggest alternative strategies for control of PPNs through RNAi approaches.
authors.affiliation: Embrapa Genetic Resources and Biotechnology, PqEB Final Av. W/5 Norte, CEP 70·770-900, Brasília, DF, Brazil.
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Gillet
authors.affiliation: Embrapa Genetic Resources and Biotechnology, PqEB Final Av. W/5 Norte, CEP 70·770-900, Brasília, DF, Brazil.
authors.forename: Caroline
authors.initials: C
authors.lastname: Bournaud
authors.affiliation: Embrapa Genetic Resources and Biotechnology, PqEB Final Av. W/5 Norte, CEP 70·770-900, Brasília, DF, Brazil.
authors.forename: Jose Dijair
authors.initials: JD
authors.lastname: Antonino de Souza Júnior
authors.affiliation: Embrapa Genetic Resources and Biotechnology, PqEB Final Av. W/5 Norte, CEP 70·770-900, Brasília, DF, Brazil.|Catholic University of Brasilia, Brasília-DF, Brazil.
authors.forename: Maria Fatima
authors.initials: MF
authors.lastname: Grossi-de-Sa
mesh_terms: D000818:Animals; D015801:Helminth Proteins / Q000235:genetics* / Q000378:metabolism; D006790:Host-Parasite Interactions; D009348:Nematoda / Q000235:genetics / Q000502:physiology*; D010935:Plant Diseases / Q000469:parasitology*; D057865:Plant Immunity; D010944:Plants / Q000469:parasitology; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D015801:Helminth Proteins; D014157:Transcription Factors
keywords: DAF pathway; DAF-16/FoxO; MAMP- and PAMP-triggered immunity; SKN-1/Nrf2; cytoprotective mechanisms; dauer; insulin/IGF-1; oxidative burst; phytoalexins; plant parasitic nematodes; reactive species