Deep Sequencing-Based Transcriptome of Brachiaria brizantha Ovaries as a Tool for Development Studies of Sexual and Apomictic Plants

Plants of Brachiaria brizantha show sexual or apomictic reproduction, with distinct morphological structure of the embryo sac (ES). Polygonum-type of ES are found in sexual plants, while in apomict plants the Panicum-type of ES is predominant. The goal of this work was to characterize gene expression profile during both sexual and apomictic development in B. brizantha. We analyzed the transcriptome of ovaries at megasporogenesis and megagametogenesis from sexual and apomictic plants, using RNA-seq. Assembly based on B. ruziziensis genome generated about 31,000 putative transcripts. Of these, 682 were differentially expressed with most (482) showing upregulation in ovaries of apomictic plants. Stage-specific genes, possibly associated with apomixis initiation and autonomous embryo development, were also identified. Relative expression levels of transcripts selected from the DGE analysis were validated by qRT-PCR. Gene onthology analysis (KEGG and PMN) was performed, pointing to the main metabolic or signaling processes associated with differentiation of the ES in both modes of reproduction. This study reports a transcriptome of developing ovaries, of sexual and apomictic plants of B. brizantha, indicating a set of genes differentially expressed during ovary development of these plants.

 Financial support: Embrapa, CAPES, CNPq