Mining the dark side of plant genomes: discovery of major peptidic hormones

Abstract

Deciphering orphan gene functions is a tricky challenge that we addressed by combining meta-analysis of transcriptomic data and expert annotation. This approach led us to discover a new family of phytocytokines involved both in Brassicaceae defenses and development through the control of ROS homeostasis that we named SCOOP (Serine riCh endOgenOus Peptide). The PROSCOOP family revealed itself as the major signaling peptide family of Arabidopsis involved in biotic stress responses. Actually, higher plant genomes encode several thousands of putative secreted peptides encoding genes. Nevertheless, the biological function of most of them is still unknown, whereas this underestimated fraction of the genomes represents a huge potential for new solutions for agro-ecology. Indeed, their detection in genomic sequences remains difficult due to their small size and limited level of conservation. To bypass the problem, we developed a bioinformatic pipeline for the prediction of genes encoding precursors of extracellular peptides, which could be applied to other species. For example, we recently identified new secreted peptides in Solanaceae species. We will present the whole approach and recent progress and discuss briefly the putative applications for the future.