Arabidopsis ribosomal RNA processing meerling mutants exhibit suspensor-derived polyembryony due to direct reprogramming of the suspensor

• DOI: 10.1093/plcell/koae087
• Publication Date: 2024-03-21T23:04:20Z
• Authors: Honglei Wang; Luca Santuari; Tristan Wijsman; Guy Wachsman; Hannah Haase; Michael Nodine; Ben Scheres; Renze Heidstra
• Keywords: Suspensor; Reprogramming

Embryo development in Arabidopsis (Arabidopsis thaliana) starts off with an asymmetric division of the zygote to generate precursors embryo proper and supporting extraembryonic suspensor. The suspensor degenerates as proceeds beyond heart stage. Until globular stage, maintains embryonic potential can form embryos absence developing proper. We report a mutant called meerling-1 (mrl-1), which shows high penetrance suspensor-derived polyembryony due delayed Eventually, from both apical lineages successfully develop into normal plants complete their life cycle. identified causal mutation genomic rearrangement altering promoter U3 SMALL NUCLEOLAR RNA-ASSOCIATED PROTEIN 18 (UTP18) homolog that encodes nucleolar-localized WD40-repeat protein involved processing 18S preribosomal RNA. Accordingly, root-specific knockout UTP18 caused growth arrest accumulation unprocessed pre-rRNA. generated mrl-2 loss-of-function observed asynchronous megagametophyte causing sac abortion. Together, our results indicate decreased abundance during early stage development, triggering embryogenesis. Our data support existence noncell autonomous signaling prevent direct reprogramming toward fate.