CHARACTERIZATION OF AN RNA-BINDING PROTEIN LRP2 IN ARABIDOPSIS

Abstract

RNA-binding proteins that mediate the post-transcriptional RNA metabolism play central regulatory roles in many developmental processes of eukaryotes. However, their functions in the floral transition, which is the key developmental process determining the reproductive success of plants, are largely unknown. Here, we show that an RNA binding protein LATE-FLOWERING RNA-BINDING PROTEIN 2 (LRP2) consisting of triple RNA recognition motifs (RRMs) promotes flowering through modulating the transcript levels of FLOWERING LOCUS C (FLC), a key floral repressor in Arabidopsis. Mutations in LRP2 greatly delay flowering because of increased FLC transcript levels. We demonstrate that LRP2 controls FLC transcript levels through both reducing the splicing efficiency of FLC introns and repressing the transcription of FLC. We also reveal that LRP2 is localized into multiple nuclear bodies and may undergo liquid-liquid phase separation in vivo. Thus, we have unraveled a new mechanism of how LRP2 controls flowering time in Arabidopsis.