Characterization and expression analysis of SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) genes in sexual and apomictic Paspalum notatum

PODIO, MARICEL; FELITTI, SILVINA ANDREA; SIENA, LORENA ADELINA; DELGADO LUCIANA; MANCINI, MICAELA ; SEIJO, JOSE GUILLERMO; GONZALES, ANA MARÍA; PESSINO, SILIVINA CLAUDIA; ORTIZ, JUAN PABLO AMELIO

PLANT MOLECULAR BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2014 vol. 84 p. 479 - 495

0167-4412

The SOMATIC EMBRYOGENESIS RECEPTORLIKEKINASE (SERK) gene plays a fundamental role insomatic embryogenesis of angiosperms, and is associatedwith apomixis in Poa pratensis. The objective of this workwas to isolate, characterize and analyze the expression patternsof SERK genes in apomictic and sexual genotypes ofPaspalum notatum. A conserved 200-bp gene fragment wasamplified from genomic DNA with heterologous primers,and used to initiate a chromosomal walking strategy forcloning the complete sequence. This procedure allowed theisolation of two members of the P. notatum SERK family;PnSERK1, which is similar to PpSERK1, and PnSERK2,which is similar to ZmSERK2 and AtSERK1. Phylogeneticanalyses indicated that PnSERK1 and PnSERK2 representparalogous sequences. Southern-blot hybridization indicatedthe presence of at least three copies of SERK genesin the species. qRT-PCR analyses revealed that PnSERK2was expressed at significantly higher levels than PnSERK1in roots, leaves, reproductive tissues and embryogenic calli.Moreover, in situ hybridization experiments revealed thatPnSERK2 displayed a spatially and chronologically alteredexpression pattern in reproductive organs of the apomicticgenotype with respect to the sexual one. PnSERK2is expressed in nucellar cells of the apomictic genotypeat meiosis, but only in the megaspore mother cell in thesexual genotype. Therefore, apomixis onset in P. notatumseems to be correlated with the expression of PnSERK2 innucellar tissue.