title: Characterization and expression analysis of SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) genes in sexual and apomictic Paspalum notatum.
abstract: The SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) gene plays a fundamental role in somatic embryogenesis of angiosperms, and is associated with apomixis in Poa pratensis. The objective of this work was to isolate, characterize and analyze the expression patterns of SERK genes in apomictic and sexual genotypes of Paspalum notatum. A conserved 200-bp gene fragment was amplified from genomic DNA with heterologous primers, and used to initiate a chromosomal walking strategy for cloning the complete sequence. This procedure allowed the isolation of two members of the P. notatum SERK family; PnSERK1, which is similar to PpSERK1, and PnSERK2, which is similar to ZmSERK2 and AtSERK1. Phylogenetic analyses indicated that PnSERK1 and PnSERK2 represent paralogous sequences. Southern-blot hybridization indicated the presence of at least three copies of SERK genes in the species. qRT-PCR analyses revealed that PnSERK2 was expressed at significantly higher levels than PnSERK1 in roots, leaves, reproductive tissues and embryogenic calli. Moreover, in situ hybridization experiments revealed that PnSERK2 displayed a spatially and chronologically altered expression pattern in reproductive organs of the apomictic genotype with respect to the sexual one. PnSERK2 is expressed in nucellar cells of the apomictic genotype at meiosis, but only in the megaspore mother cell in the sexual genotype. Therefore, apomixis onset in P. notatum seems to be correlated with the expression of PnSERK2 in nucellar tissue.
authors.affiliation: Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario (UNR), Campo Experimental Villarino, CC 14 (S2125ZAA), Zavalla, Santa Fe, Argentina.
authors.forename: Maricel
authors.initials: M
authors.lastname: Podio
authors.forename: Silvina Andrea
authors.initials: SA
authors.lastname: Felitti
authors.forename: Lorena Adelina
authors.initials: LA
authors.lastname: Siena
authors.forename: Luciana
authors.initials: L
authors.lastname: Delgado
authors.forename: Micaela
authors.initials: M
authors.lastname: Mancini
authors.forename: José Guillermo
authors.initials: JG
authors.lastname: Seijo
authors.forename: Ana María
authors.initials: AM
authors.lastname: González
authors.forename: Silvina Claudia
authors.initials: SC
authors.lastname: Pessino
authors.forename: Juan Pablo A
authors.initials: JP
authors.lastname: Ortiz
mesh_terms: D000595:Amino Acid Sequence; D060832:Apomixis / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000235:genetics; D008969:Molecular Sequence Data; D031781:Paspalum / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D011494:Protein Kinases / Q000145:classification / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000196:embryology / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D007527:Isoenzymes; D010940:Plant Proteins; D011494:Protein Kinases