ZmARF1 positively regulates low phosphorus stress tolerance via modulating lateral root development in maize

In this study, we found that the transcription factorZmARF1 was associated with low inorganic phosphate (Pi) stress-related traits in maize. This superior root morphology and greater phosphate stress tolerance could be ascribed to the overexpression ofZmARF1. The knock out mutantzmarf1 had shorter primary roots, fewer root tip number, and lower root volume and surface area. Transcriptomic data indicate thatZmLBD1, a direct downstream target gene, is involved in lateral root development, which enhances phosphate starvation tolerance. A transcriptional activation assay revealed thatZmARF1 specifically binds to the GC-box motif in the promoter ofZmLBD1 and activates its expression. Moreover,ZmARF1 positively regulates the expression ofZmPHR1,ZmPHT1;2, andZmPHO2, which are key transporters of Pi in maize. We propose thatZmARF1 promotes the transcription ofZmLBD1 to modulate lateral root development and Pi-starvation induced (PSI) genes to regulate phosphate mobilization and homeostasis under phosphorus starvation. In addition, ZmERF2 specifically binds to the ABRE motif of the promoter ofZmARF1 and represses its expression. Collectively, the findings of this study revealed thatZmARF1 is a pivotal factor that modulates root development and confers low-Pi stress tolerance through the transcriptional regulation of the biological function ofZmLBD1 and the expression of key Pi transport proteins.

Source: PLoS Genetics - February 5, 2024 Category: Genetics & Stem Cells Authors: Fengkai Wu Source Type: research