An ABCC-type transporter endowing glyphosate resistance in plants

Area of Science:

• Plant Science
• Molecular Biology
• Biochemistry

Background:

• Glyphosate is a widely used herbicide, leading to widespread evolution of glyphosate-resistant (GR) weeds.
• Understanding the molecular mechanisms behind glyphosate resistance is crucial for sustainable agriculture.

Purpose of the Study:

• To identify the molecular basis of glyphosate resistance in a GR *Echinochloa colona* population.
• To investigate the role and conservation of the identified gene in conferring glyphosate resistance across different plant species.

Main Methods:

• Identification and characterization of an ATP-binding cassette (ABC) transporter (EcABCC8) in GR *Echinochloa colona*.
• Functional analysis using transgenic rice, maize, and soybean overexpressing *EcABCC8* or its orthologs.
• CRISPR/Cas9-mediated gene knockout in rice to assess gene function.
• Subcellular localization and glyphosate quantification studies.

Main Results:

• An ATP-binding cassette (ABC) transporter, *EcABCC8*, was consistently up-regulated in GR *Echinochloa colona*.
• Overexpression of *EcABCC8* or its orthologs in rice, maize, and soybean conferred glyphosate resistance.
• Knockout of the rice ortholog *OsABCC8* increased susceptibility to glyphosate.
• EcABCC8 functions as a plasma membrane transporter, extruding glyphosate from the cytoplasm.

Conclusions:

• A novel mechanism of glyphosate resistance involving an ABC transporter (*EcABCC8*) that effluxes glyphosate has been identified in *Echinochloa colona*.
• This efflux mechanism is conserved and functional in major crop species like rice, maize, and soybean.
• The findings provide a potential target for developing new strategies to manage glyphosate-resistant weeds or enhance crop tolerance.