Temporal and spatial expression patterns of the auxin-responsive gene PnIAA30 in sexual and apomictic Paspalum notatum

AZZARO, CELESTE; SIENA, LORENA; PODIO, MARICEL; STEIN, JULIANA; PESSINO, SILVINA; ORTIZ, JUAN PABLO

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 angiospermspecies. This trait seems to derive from a deregulation of the sexual developmental programoccurring in ovules. In Paspalum notatum, apomixisis controlled by a heterochromatic nonrecombinant 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) genes IAA30. Aux/IAA family members play several roles in plant development by interacting with auxin response factors. Here, we analyzed the expression patterns of the P. notatum IAA30 ortholog/s in reproductive organs of sexual and apomictic genotypes. BLASTn/x searches in P. 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 strandwas expressed in ovaries and microspores of both genotypes, but no hybridization was detectedin 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 P. notatum reproductive development and one ortholog of OsIAA30 showed expression differences between sexual and apomictic ovaries.