1.- Perform a transcriptome characterization of the mussel Mytilus chilensis and Mesodesma donacium challenged by Alexandrium catenella using 454 pyrosequencing. 2.- Perform an in silico analysis to discover and identify candidate genes associated to immune response against HAB 3.- Determine the association of immune-related genes expression in several bivalve tissues exposed to A. catenella 4.- Establish expression patterns of candidate genes and cell responses on short-term hemocyte cultures challenged to both A. catenella and SXT 5.- Determine the variation of gene expression among individuals from different populations for M. chilensis and M. donacium