Chapter 16: MOA Part 2: Amino Acid Synthesis Inhibitors & Nitrogen Metabolism Inhibitors
16.10 Summary
In this chapter we spent some time discussing basic biological concepts regarding the importance of proteins and amino acids in plant growth and development. We then compared branched chain amino acids and aromatic amino acids, which then launched us into the key biochemical pathways for them. This led us to discussing the key sites of action that herbicides target and the adverse effects on susceptible plants, as well as common injury symptoms. Finally, in this chapter we addressed herbicide resistance found in crops, as well as weed populations.
Key Takeaways
Key takeaways from this chapter include:
- Amino acids make up proteins, which are responsible for catalyzing chemical reactions, facilitating membrane transport, building intracellular structures and energy generating reactions involving electron transport.
- A protein’s shape determines its function.
- Amino Acid Synthesis Inhibitors include Group 2 ALS Inhibitors and Group 9 EPSP Inhibitors.
- ALS Inhibitors interfere with formation of branched chain amino acids. EPSP Inhibitors interfere with the formation of aromatic amino acids.
- There are currently more weed species resistant to branched chain amino acid inhibitors than any other herbicide MOA (49 in the US).
- Nitrogen Metabolism Inhibitors (Group 10) block the enzyme glutamine synthetase resulting in a toxic buildup of ammonia and the lack of amino acid glutamine.
- Glufosinate is a Nitrogen Metabolism Inhibitor.