A Systematic Search for RNase-based Self-incompatibility

Most flowering plant species have co-sexual individuals whose own pollen often lands on their own stigmas. And yet, approximately one-half are self-incompatible---they cannot self-fertilize. Instead, individuals commonly express a genetic mechanism that sorts and differentially rejects incoming pollen. Many mechanisms exist, but one, RNase-based self-incompatibility, is potentially widespread. Although it is found across eudicots, it has only been characterized in a handful of species in distantly related families. My work has uncovered the presence of this mechanism in at least two new flowering plant families: Cactaceae and Primulaceae. These findings yield additional evidence that the ancestor of nearly all eudicots possessed RNase-based self-incompatibility. The RNA-seq based approach and the associated bioinformatics pipeline are promising and could open doors for work on difficult species such as trees and other long-lived plants.