Role of AHL Proteins in Lateral Root Formation

AT-HOOK MOTIF NUCLEAR-LOCALIZED PROTEIN (AHL) terrestrial plant specific gene family of small nuclear proteins with two characteristic domains. AT-hook domain allows them to bind DNA in specific sites and PPC domain (Plant and Procaryotes Conserved) is responsible for nuclear localization, oligomerization and interaction with other proteins. AHLs are known to modulate transcription in various ways.

We have identified via a gene trap line screening AHL18 (AT3G60870) being expressed in xylem adjacent sector of pericycle and developing primordia of lateral roots. Phenotype analysis of insertion knock-out mutants of ahl18 and plants with 35S overexpression of AHL18 consistently modify total number of lateral roots. The source of this variation is not in the initiation, but latter development and activation of lateral root meristem before emergence. The root system architecture change of ahl18 is thus connected with higher percentage of non-developing primordia. This phenotype of significant reduction of root system was further enhanced in multiple AHLs knock out mutants. However, such effect is bound to specific combination of AHLs.

Hereby, we describe the novel regulatory mechanism taking part in shaping root system architecture.

We thank NPUI LO1417 and GAUK 410216 for support.