title: Differential expression of G protein alpha and beta subunit genes during development of Phytophthora infestans.
abstract: A G protein alpha subunit gene (pigpa1) and a G protein beta subunit gene (pigpb1) were isolated from the oomycete Phytophthora infestans, the causal agent of potato late blight. Heterotrimeric G proteins are evolutionary conserved GTP-binding proteins that are composed of alpha,beta, and gamma subunits and participate in diverse signal transduction pathways. The deduced amino acid sequence of both pigpa1 and pigpb1, showed the typical conserved motifs present in Galpha or Gbeta proteins from other eukaryotes. Southern blot analysis revealed no additional copies of Galpha or Gbeta subunit genes in P. infestans, suggesting that pigpa1 and pigpb1 are single copy genes. By cross-hybridization homologues of gpa1 and gpb1 were detected in other Phythophthora species. Expression analyses revealed that both genes are differentially expressed during asexual development, with the highest mRNA levels in sporangia. In mycelium, no pigpa1 mRNA was detected. Western blot analysis using a polyclonal GPA1 antibody confirmed the differential expression of pigpa1. These expression patterns suggest a role for G-protein-mediated signaling during formation and germination of asexual spores of P. infestans, developmental stages representing the initial steps of the infection process.
authors.affiliation: Laboratory of Phytopathology, Graduate School Experimental Plant Sciences, Wageningen University, Wageningen, The Netherlands.
authors.forename: Ana
authors.initials: A
authors.lastname: María Laxalt
authors.forename: Maita
authors.initials: M
authors.lastname: Latijnhouwers
authors.forename: Marieke
authors.initials: M
authors.lastname: van Hulten
authors.forename: Francine
authors.initials: F
authors.lastname: Govers
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D018507:Gene Expression Regulation, Developmental; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010838:Phytophthora / Q000235:genetics* / Q000254:growth & development; D016415:Sequence Alignment
chemical_list: D020962:Heterotrimeric GTP-Binding Proteins