ZmGDI1 Modulates Stomatal Development and Drought Response via the Rho GTPase Pathway Regulation in Maize

Area of Science:

• Plant Biology
• Molecular Plant Science
• Cell Signaling

Background:

• Guanine nucleotide dissociation inhibitors (GDIs) are known regulators of cell signaling in mammals.
• The function of GDIs in plant stomatal development and stress responses is currently unknown.
• Stomatal development is critical for plant gas exchange and water balance.

Purpose of the Study:

• To investigate the role of maize GDI1 (ZmGDI1) in stomatal formation.
• To determine the involvement of ZmGDI1 in plant drought stress responses.
• To elucidate the molecular mechanism by which ZmGDI1 regulates stomatal development.

Main Methods:

• Heterologous expression of ZmGDI1 in Arabidopsis thaliana.
• Analysis of atgdi1 loss-of-function mutants.
• Virus-induced gene silencing (VIGS) in maize.
• Biochemical assays to determine protein interactions and activity inhibition.

Main Results:

• ZmGDI1 expression in Arabidopsis reduced stomatal density and key stomatal development gene transcription.
• Loss-of-function atgdi1 mutants showed increased stomatal density and enhanced drought sensitivity.
• ZmGDI1 rescued atgdi1 mutant phenotypes, confirming conserved function.
• ZmGDI1 interacts with and inhibits Rho GTPase ZmROP4, impacting stomatal development.
• ZmGDI1-silenced maize exhibited increased stomatal density.

Conclusions:

• A conserved GDI-ROP signaling module regulates stomatal patterning in plants.
• ZmGDI1 plays a crucial role in controlling stomatal density and drought tolerance.
• This study identifies ZmGDI1 as a potential molecular target for engineering drought-tolerant crops.