Characterization of feruloyl esterases in maize pollen

Area of Science:

• Plant Biology
• Biochemistry
• Molecular Biology

Background:

• Maize (Zea mays) seed production relies on pollen fertilization.
• Pollen tubes must penetrate feruloylated arabinoxylan/cellulose-rich silk and stigma tissues.
• Pollen surfaces possess cell wall hydrolases, including endo-xylanase (ZmXYN1).

Purpose of the Study:

• To identify and characterize ferulic acid esterases (FAEs) in maize pollen.
• To investigate the role of maize pollen FAEs in pollen fertilization.

Main Methods:

• Biochemical purification and characterization of FAEs from maize pollen.
• Analysis of FAE expression during pollen development.
• Assays measuring ferulate release from plant cell walls.
• Synergistic activity studies with fungal endo-1,4-β-xylanase.
• Analysis of ferulate levels in maize silk cell walls post-pollination.

Main Results:

• Ferulic acid esterases (FAEs) were identified and partially purified from maize pollen.
• Maize pollen FAEs are expressed early in pollen development.
• FAEs effectively released ferulates and diferulates from maize silks and grass cell walls.
• FAEs showed synergistic activity with fungal endo-1,4-β-xylanase in releasing ferulates.
• A significant reduction in esterified ferulates was observed in maize silk cell walls after pollination.

Conclusions:

• Maize pollen FAEs are important hydrolases involved in pollen fertilization.
• These enzymes likely facilitate pollen tube growth through the stigma and silk.
• Maize pollen FAEs may play a significant role in maize seed production.