Chloroplast Engineering for Herbicide Resistance via Enolpyruvylshikimatephosphate Synthase

Introduction

Enolpyruvylshikimatephosphate synthase (EPSPS), also known as 5-enolpyruvate shikimate-3-phosphate synthase, is an enzyme in the shikimate pathway. This enzyme is essential for the synthesis of aromatic amino acids and many aromatic metabolites in plants, fungi and microorganisms. In plants, EPSPS localizes in the chloroplast to function and has become an attractive target for herbicides. Glyphosate (N-phosphonomethylglycine) is an important and effective herbicide widely used to control weeds in agricultural fields. Studies have shown that EPSPS is the primary target of glyphosate, and that inhibition of EPSPS shuts down the shikimate pathway in a complex manner, resulting in plant death. At present, EPSPS has become the first choice for the development of transgenic glyphosate-tolerant crops.

Fig. 1. Classification of the EPSPS for assessing sensitivity of organisms to the herbicide. (Leino L, et al., 2021)

Solutions

Since the target of glyphosate exists in the chloroplast, the chloroplast transgenic transformation of EPSPS has successfully achieved glyphosate tolerance engineering in major crops. Because of glyphosate's broad spectrum, effective weed control and favorable environmental properties, our engineers have been working hard to engineer glyphosate resistance by encoding insensitive EPSPS genes. Here, Lifeasible provides the development of glyphosate-tolerant crops by inserting a novel aroA gene encoding EPSPS with high levels of glyphosate tolerance into the chloroplast genome, thereby increasing crop yield. In addition, we offer two other strategies to make crops resistant to glyphosate.

(1) The cultured plant cells gradually adapt to the gradual increase of the glyphosate concentration to obtain glyphosate resistance.

(2) Resistance is achieved by transforming plants with glyphosate-metabolizing genes, including glyphosate oxidoreductase (GOX) and N-acetyltransferase.

Bioinformatics-based analysis of glyphosate susceptibility or resistance, taxonomic distribution and domain architecture. We have successfully cloned many glyphosate-resistant aroA genes from bacteria and engineered them into the chloroplast genomes of crops such as tobacco and tomato. Our available solutions for herbicide resistant via EPSPS include:

• Cloning and purification of EPSPS.
• Kinetic characterization of EPSPS enzymes.
• X-ray structure and modeling of EPSPS.
• Expression of EPSPS in crops such as soybean and corn.
• Confering glyphosate tolerance to corn and soybeans.

Features of Our Strategy

• Stable integration can increase glyphosate resistance even above lethal concentrations.
• Chloroplasts express much higher levels of glyphosate-resistant EPSPS enzymes than nuclear transformation.
• Increased levels of glyphosate-resistant EPSPS were not associated with increased glyphosate tolerance.
• EPSPS are generally sensitive to glyphosate and are mainly derived from plants and bacteria.
• The tolerance of EPSP to glyphosate was analyzed based on multiple criteria, including sequence similarity, intrinsic kinetic properties, etc.

The insensitive EPSPS gene was transformed into plant chloroplasts showed obvious glyphosate resistance. Lifeasible has extensive knowledge and experience in the engineering of herbicide resistance via herbicide-insensitive enzymes. Our mission is to provide customers with comprehensive, reliable, professional solutions to accelerate your research. If you are interested in our solutions, please contact us at any time.

References

1. Leino L, Tall T, Helander M, et al. (2021) Classification of the glyphosate target enzyme (5-enolpyruvylshikimate-3-phosphate synthase) for assessing sensitivity of organisms to the herbicide[J]. Journal of Hazardous Materials. 408: 124556.
2. Daniell H, Datta R, Varma S, et al. (1998) Containment of herbicide resistance through genetic engineering of the chloroplast genome. Nat Biotechnol. 16(4): 345-348.