Glyphosphate

Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting a plant enzyme involved in the synthesis of three aromatic amino acids: tyrosine, tryptophan, and phenylalanine. This inhibition leads to the disruption of protein synthesis in plants, effectively killing them. Glyphosate is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. It was discovered to be an herbicide by Monsanto chemist John E. Franz in 1970. Monsanto brought it to market in the 1970s under the trade name Roundup, and its agricultural use has greatly increased since the development of crops that are genetically modified to make them resistant to glyphosate.

History

Glyphosate was first synthesized in 1950 by Swiss chemist Henry Martin, but its herbicidal properties were not discovered until 20 years later by John E. Franz, a chemist working for Monsanto. Since its introduction in the 1970s, glyphosate has become the most widely used herbicide in the United States and globally. Its usage expanded significantly with the introduction of glyphosate-resistant genetically modified (GM) crops in the 1990s.

Usage

Glyphosate is used in agriculture and forestry, for lawn and garden maintenance, and on industrial sites where weed control is necessary. It is applied to the leaves of plants to kill both broadleaf plants and grasses. The sodium salt form of glyphosate is used to regulate plant growth and ripen specific crops.

Mechanism of Action

The mechanism by which glyphosate kills plants is by inhibiting the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). This enzyme is part of the shikimic acid pathway, a metabolic route that is essential for the biosynthesis of the aromatic amino acids tyrosine, tryptophan, and phenylalanine. These amino acids are vital for protein synthesis and plant growth. By inhibiting EPSPS, glyphosate disrupts the production of these amino acids, leading to the death of the plant.

Environmental Impact

The widespread use of glyphosate has raised concerns regarding its environmental impact. Studies have shown that glyphosate can have various effects on non-target species, including aquatic organisms and birds. Its persistence in soil and water, as well as its potential for bioaccumulation, are areas of ongoing research and debate.

Health Concerns

The health effects of glyphosate on humans are controversial. Some studies have suggested a potential link between glyphosate exposure and cancer, specifically non-Hodgkin lymphoma, while others have found no significant risk. In 2015, the International Agency for Research on Cancer (IARC), a part of the World Health Organization (WHO), classified glyphosate as "probably carcinogenic in humans." However, other regulatory agencies, including the European Food Safety Authority (EFSA) and the U.S. Environmental Protection Agency (EPA), have concluded that glyphosate is unlikely to pose a carcinogenic risk to humans.

Regulation

The regulation of glyphosate varies by country, with some countries banning or restricting its use and others continuing to approve it. The debate over glyphosate's safety and environmental impact continues to influence regulatory decisions worldwide.