Plant-specific LOB-domain (LBD) transcription factors are crucial in post-embryonic root initiation. In cereals, the fibrous root system comprises primary and seminal roots that develop during embryogenesis and lateral- and crown roots that develop post-embryonically from root or stem, respectively. In rice, the CROWNROOTLESS1 (CRL1) LBD transcription factor is the core regulator of crown root initiation and a direct target of...