The mRNA decapping machinery targets to mediate apical hook and lateral root development.

Multicellular organisms perceive and transduce multiple cues to optimize development. Key transcription factors drive developmental changes, but RNA processing also contributes to tissue development. Here, we report that multiple decapping deficient mutants share developmental defects in apical hook, primary and lateral root growth. More specifically, transcripts accumulate in decapping deficient plants and can be found in complexes with decapping components. Accumulation of inhibits apical hook and lateral root formation. Interestingly, exogenous auxin application restores lateral roots formation in both over-expressors and mRNA decay-deficient mutants. Likewise, mutations in the cytokinin transcription factors type-B ARABIDOPSIS RESPONSE REGULATORS (B-ARRs) and restore the developmental defects caused by over-accumulation of capped transcript upon overexpression. Most importantly, loss-of-function of partially restores apical hook and lateral root formation in both and triple decapping deficient mutants. Thus, the mRNA decay machinery directly targets transcripts for decay, possibly to interfere with cytokinin/auxin responses, during development.