Transcriptomics, also referred to as expression profiling, is the investigation of a set (or all) RNA molecules expressed in a certain tissue or cell type, in a specific developmental stage, or under certain physiological conditions. Besides expression profiling, transcriptomics serves as a screening tool for candidate gene discovery.
We are manually isolating living cells from flowering plant female and male gametophytes by micromanipulation with the aim to study the transcriptome of these cells. Previously, we used female gametes (egg cells and central cells) and two-celled proembryos of wheat and Arabidopsis to perform either single-run partial sequencing of randomly selected cDNA clones (ESTs; “expressed sequence tags”) of generated cDNA libraries (Sprunck et al., 2005), or microarray-based expression profiling (Englhart et al., 2017). Meanwhile, we perform next-generation sequencing (NGS) to investigate the RNA and small RNA content of female and male gametophytic cells from different flowering plant species.
We are analyzing our transcriptome data sets with the aim to discover uncharacterized gamete-specific or early fertilization-induced mRNAs, as well as small and long noncoding RNAs. We identified, for example, transcripts specifically present in the egg cell and/or the central cell and transcripts specifically induced in zygotes and two-celled proembryos (Chen et al., 2017; Leljac-Levanic et al., 2013; Sprunck et al., 2012; Juranic et al., 2012; Sprunck et al., 2005). Currently, we investigate the molecular function of selected candidate genes/gene families participating in the establishment of cell polarity, in gamete specification, and in gamete interactions during double fertilization.
