title: Harnessing apomictic reproduction in grasses: what we have learned from Paspalum.
abstract: BACKGROUND
  Apomixis is an alternative route of plant reproduction that produces individuals genetically identical to the mother plant through seeds. Apomixis is desirable in agriculture, because it guarantees the perpetuation of superior genotypes (i.e. heterotic hybrid seeds) by self-seeding without loss of hybrid vigour. The Paspalum genus, an archetypal model system for mining apomixis gene(s), is composed of about 370 species that have extremely diverse reproductive systems, including self-incompatibility, self-fertility, full sexual reproduction, and facultative or obligate apomixis. Barriers to interspecific hybridization are relaxed in this genus, allowing the production of new hybrids from many different parental combinations. Paspalum is also tolerant to various parental genome contributions to the endosperm, allowing analyses of how sexually reproducing crop species might escape from dosage effects in the endosperm.
  
  
  METHODS
  In this article, the available literature characterizing apomixis in Paspalum spp. and its use in breeding is critically reviewed. In particular, a comparison is made across species of the structure and function of the genomic region controlling apomixis in order to identify a common core region shared by all apomictic Paspalum species and where apomixis genes are likely to be localized. Candidate genes are discussed, either as possible genetic determinants (including homologs to signal transduction and RNA methylation genes) or as downstream factors (such as cell-to-cell signalling and auxin response genes) depending, respectively, on their co-segregation with apomixis or less. Strategies to validate the role of candidate genes in apomictic process are also discussed, with special emphasis on plant transformation in natural apomictic species.
authors.affiliation: Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina.
authors.forename: Juan Pablo A
authors.initials: JP
authors.lastname: Ortiz
authors.forename: Camilo L
authors.initials: CL
authors.lastname: Quarin
authors.forename: Silvina C
authors.initials: SC
authors.lastname: Pessino
authors.forename: Carlos
authors.initials: C
authors.lastname: Acuña
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Martínez
authors.forename: Francisco
authors.initials: F
authors.lastname: Espinoza
authors.forename: Diego H
authors.initials: DH
authors.lastname: Hojsgaard
authors.forename: Maria E
authors.initials: ME
authors.lastname: Sartor
authors.forename: Maria E
authors.initials: ME
authors.lastname: Cáceres
authors.forename: Fulvio
authors.initials: F
authors.lastname: Pupilli
mesh_terms: D060832:Apomixis / Q000235:genetics / Q000502:physiology*; D001947:Breeding; D002874:Chromosome Mapping; D017343:Genes, Plant / Q000235:genetics; D031781:Paspalum / Q000235:genetics / Q000502:physiology*; D006109:Poaceae / Q000235:genetics / Q000502:physiology*; D012098:Reproduction; D015398:Signal Transduction; D014170:Transformation, Genetic
keywords: Apomixis; Paspalum; comparative mapping; molecular markers; transcriptomic analysis