<i>ZmARF1</i> conferred Pi stress tolerance by promoting root development.

Overexpression and knockout mutants of ZmARF1, and WT at the 3-leaf stage were transferred to (A) HP and (B) LP for 14 days and evaluated for growth and root development. Phenotypic traits: (C) Root-to-shoot ratio, (D) Shoot fresh weight, (E) Root fresh weight, (F) Total root length, (G) Total root tip number, and (H) Root surface area, were evaluated after HP and LP treatment. Three biological repeats were treated; more than 9 plants of each genotype were used for each biological repeat. Means are presented as bar graphs and error bars represent standard deviation. OE1# and OE2# represent the two overexpression lines, WT is the wild-type, KO-G# and KO-CG# are two knockout mutants. *, P t test).