Homologous genes of epidermal patterning factor regulate stomatal development in rice

Area of Science:

• Plant Biology
• Molecular Genetics
• Plant Physiology

Background:

• Stomata are crucial leaf pores regulating gas exchange (water vapor, CO2) essential for photosynthesis.
• The Epidermal Patterning Factor (EPF) family of signaling peptides controls stomatal development and density in Arabidopsis.
• Rice (Oryza sativa) possesses putative homologs of EPF/EPFL genes, suggesting conserved roles in plant development.

Purpose of the Study:

• To investigate the function of rice EPF/EPFL homologs in regulating stomatal formation and density.
• To compare the roles of rice EPF/EPFL genes in rice with their known functions in Arabidopsis.

Main Methods:

• Generation of transgenic rice lines with reporter promoter fusions, gene down-regulation, and gene overexpression.
• Analysis of stomatal density in various transgenic rice genotypes.
• Ectopic overexpression of rice EPF/EPFL genes in Arabidopsis mutants (epf2, epf1epf2) to assess functional conservation.

Main Results:

• Elevated expression of OsEPF1 or OsEPF2 significantly reduced stomatal density in rice.
• Knocking down OsEPFL9 transcription decreased stomatal density in rice compared to wild-type (WT).
• Ectopic overexpression of OsEPF1 or OsEPF2 in Arabidopsis mutants reduced stomatal frequency, while OsEPFL9 overexpression in Arabidopsis caused excessive stomata production.

Conclusions:

• Rice EPF/EPFL homologs play a conserved role in regulating stomatal development.
• Functional distinctions exist between dicot (Arabidopsis) and monocot (rice) EPF/EPFL genes in controlling stomatal density.