Abstract
Multicellular organisms perceive and transduce multiple cues to optimize development and cell state switching. Key transcription factors drive developmental changes, but transitions also require the attenuation of previous states and removal of negative regulators. Here, we report shared developmental defects in apical hook, primary and lateral root growth in multiple decapping deficient mutants. The mRNA levels of LATERAL ORGAN BOUNDARIES DOMAIN 3 (LBD3)/ASYMMETRIC LEAVES 2-LIKE 9 (ASL9) transcription factor are directly regulated by mRNA decapping machinery. More specifically, ASL9 transcripts accumulate in decapping deficient plants and can be found in complexes with decapping components. Accumulation of ASL9 inhibits apical hook, primary root growth and lateral root formation. Interestingly, exogenous auxin application restores lateral roots formation in both ASL9 over-expressors and mRNA decay-deficient mutants. Moreover, mutations in the cytokinin transcription factors type-B ARABIDOPSIS RESPONSE REGULATORS (B-ARRs) ARR10 and ARR12 restore the developmental defects caused by over-accumulation of capped ASL9 transcript upon ASL9 overexpression. Most importantly, loss-of-function of asl9 partially restores apical hook, primary root growth and lateral root formation in decapping deficient mutants. Thus, the mRNA decay machinery directly targets ASL9 transcripts for decay to balance cytokinin/auxin responses during development.
Competing Interest Statement
The authors have declared no competing interest.