Studies tending to functionally characterize putative genes to be involved in apomictic pathway/s in Eragrostis curvula

Abstract

Apomixis (asexual seed formation) is a plant ability to bypass sexual reproduction. Without male fertilization, the resulting seed germinates a plant that develops as a maternal clone. This reproductive mode has been documented in many flowering plant species; however main seed crops have not been shown to be capable of apomictic propagation. Eragrostis curvula (Schrad.) Nees (weeping lovegrass) is a high photosynthetically-efficient C4 perennial grass, member of the Poaceae family. Weeping lovegrass includes cytotypes with different ploidy levels (from 2X to 8X) and reproductive modes, being mainly an apomictic species. In previous transcriptomic analysis, we have identified several genes displaying differential representation in florets of sexual and apomictic genotypes, suggesting they might be involved in apomictic pathways. Many of these genes do not have an annotation in other species, therefore it is necessary to functionally characterize them. In an attempt to achieve this characterization, we addressed different approaches: a) RNA in situ hybridization technic (RNA-ISH) to determine the expression patterns cell-specific of these genes in reproductive tissues of full apomictic and sexual genotypes; b) expression in rice under different constitutive promoters. In this work, we summarize some results obtained with these techniques on one of the differentially expressed genes. RNA-ISH experiments revealed its differential expression pattern in reproductive tissues, specifically being expressed in ovule tissues of full apomictic plants. Transgenic assays allowed us to obtain different independent lines overexpressing this gene that are currently under phenotypic analysis. These studies will lead to understand the potential role of this gene in apomictic reproduction pathways.