Temporal and spatial expression of the auxin induced protein IAA30 and its possible association with apomixis in Paspalum notatum.

AZZARO CELESTE ANTONELA; PESSINO SILVINA CLAUIDIA; PODIO, MARICEL; SIENA LORENA ADELINA; ORTIZ JAUN PABLO AMELIO

Mendoza

Congreso; XVII Congreso Latinoamericano de Genética.; 2019

Sociedad Argentina de Genética

Apomixis is an asexual mode of reproduction by seeds described in more than 400 angiosperm species. This trait seems to derive from a deregulation of the sexual developmental program occurring in ovules. In Paspalum notatum, apomixis is controlled by a heterochromatic non-recombinant genomic region (ACR, after Apospory Controlling Region). Comparative mapping revealed that the ACR is syntenic to a short segment of rice chromosome 12. The locus LOC_Os12g40890 maps in this region and encodes for the auxin responsive (Aux/IAA) gene OsIAA30. Aux/IAA family members play several roles in plant development by interacting with auxin response factors. Here, we analyzed the expression patterns of the Paspalum notatum IAA30 ortholog/s in reproductive organs of sexual and apomictic genotypes. BLASTn/x searches in Paspalum notatum floral transcriptomes identified 5 Aux/IAA transcripts. One of them, PnIAA30, showed a slight but significant differential expression in apomictic and sexual libraries. qRT-PCR at meiosis and anthesis confirmed the expression differences. In situ hybridization showed that the coding strand was expressed in ovaries and microspores of both genotypes, but no hybridization was detected in the MMCs of the sexual genotype. At anthesis strong signals were detected in nucellar cells, polar nuclei and egg apparatus of sexual ovaries. Results indicate that Aux/IAA genes are expressed during the Paspalum notatum reproductive development and one ortholog of OsIAA30 showed expression differences between sexual and apomictic ovaries.