Expression analysis of N19, a gene related with sexual and apomictic development in Paspalum notatum

SARTOR M; ESPINOZA F; SEIJO G; GONZÁLEZ AM; PESSINO S

Rosario

Congreso; XV Congreso Latinoamericano de Genética; 2012

Sociedad Argentina de Genética

In former expression analysis aimed at identifying genes differentially expressed in reproductive tissues of apomictic and sexual genotypes, we isolated a candidate DET (differentially expressed tag, experimental code N19) which kept similarity with checkpoint homologue CHK1. This candidate showed a high expression level, was upregulated in sexual plants and mapped in silico onto the rice chromosomal region syntenic to the P. notatum apospory-controlling locus. The objective of this work was to better characterize N19 structure and expression in reproductive tissues of apomictic and sexual plants. Relative expression quantitation using q-RTPCR experiments revealed heterochronic temporal expression patterns, with minor upregulation in apomictic plant at premeiosis and meiosis, downregulation at postmeiosis and equal expression at anthesis. Spatial expression patterns were examined by using in situ RNA hybridization experiments on reproductive tissues at meiosis and anthesis. During meiosis, the antisense probe revealed a strong signal in the megaspore mother cell (MMC), teguments and nucella of the apomictic plant, but only in the MMC of the sexual plant. In anthesis, both reproductive types (apomictic and sexual) displayed a uniform expression pattern when hybridized with the antisense probe, displaying signal in teguments, egg apparatus and polar nuclei. No signal was observed in hybridizations with the sense probe. Rapid amplification of cDNA ends (RACE) experiments allowed the isolation of single bands, which will be sequenced in order to characterize the transcript full-length structure. Our results showed that candidate N19 expression was de-regulated (upregulated) in teguments and nucella of the apomictic plants at meiosis.