RT Journal Article SR Electronic T1 LARP6C regulates selective mRNA translation to promote pollen tube guidance in Arabidopsis thaliana JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.11.27.401307 DO 10.1101/2020.11.27.401307 A1 Elodie Billey A1 Said Hafidh A1 Isabel Cruz-Gallardo A1 Celso G. Litholdo, Jr A1 Viviane Jean A1 Marie-Christine Carpentier A1 Claire Picart A1 Katarina Kulichova A1 David Honys A1 Maria R. Conte A1 Jean-Marc Deragon A1 Cécile Bousquet-Antonelli YR 2020 UL http://biorxiv.org/content/early/2020/11/27/2020.11.27.401307.abstract AB In angiosperms, non-motile sperm cells are delivered to the ovules for fertilization via a guided growth of the pollen tube. RNA binding proteins are key regulators that control mRNA fate post-transcriptionally and thus essential for normal cell function. But very little is known on the mechanistic bases of mRNA regulations and trans-acting factors governing male-female signalling. Here we demonstrate that the evolutionarily conserved RNA binding protein LARP6C is necessary for pollen tube guidance and fertilization. larp6c loss-of-function mutants exhibit male induced fertility defects as mutant pollen tubes frequently are unable to find ovules for fertilization. In mature pollen, LARP6C localises with a pollen specific poly(A) binding protein to cytoplasmic foci likely containing mRNPs. With RNA immunoprecipitation and sequencing, we demonstrate that LARP6C is associated in vivo with mRNAs required for pollen tube guidance or polarized cell growth. We further demonstrate using in vitro and in planta transient assays that LARP6C binds 5’-UTR box motifs to orchestrate the balance between translation, decay and storage of its mRNA targets. We propose a model where LARP6C maintains its mRNA target in translationally silent state likely to promote localized translation and guided pollen tube growth upon paracrine signalling.Competing Interest StatementThe authors have declared no competing interest.