The herbicide glyphosate is effectively detoxified by N-acetylation. We screened a collection of microbial isolates and discovered enzymes exhibiting glyphosate N-acetyltransferase (GAT) activity. Kinetic properties of the discovered enzymes were insufficient to confer glyphosate tolerance to transgenic organisms. Eleven iterations of DNA shuffling improved enzyme efficiency by nearly four orde...

A key enzyme in the shikimate pathway, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) is the primary target of the broad-spectrum herbicide glyphosate. Identification of new aroA genes coding for EPSPS with a high level of glyphosate tolerance is essential for the development of glyphosate-tolerant crops. In the present study, the glyphosate tolerance of five bacterial aroA genes was evalu...

The effect of exposure of Aedes aegypti larvae for 72h to sub-lethal concentrations of the herbicide glyphosate and the polycyclic aromatic hydrocarbon benzo[a]pyrene on their subsequent tolerance to the chemical insecticides imidacloprid, permethrin and propoxur, detoxification enzyme activities and transcription of detoxification genes was investigated. Bioassays revealed a significant increa...

Glyphosate is the most widely used herbicide for its low cost and high efficiency. However, it is rarely applied directly in rice field due to its toxicity to rice. Therefore, glyphosate-tolerant rice can greatly decrease the cost of rice production and provide a more effective weed management strategy. Although, several approaches to develop transgenic rice with glyphosate tolerance have been ...

The evolution of glyphosate-resistant Palmer amaranth is the result of overreliance on glyphosate alone for weed control in glyphosate-resistant crops. It is believed that the use of reduced glyphosate rates may have contributed to the evolution of resistance in Palmer amaranth; however, data to support this hypothesis are lacking. Therefore, an experiment was conducted in the greenhouse at the...

N-Acetylation is a modification of glyphosate that could potentially be used in transgenic crops, given a suitable acetyltransferase. Weak enzymatic activity (k(cat) = 5 min(-1), K(M) = 1 mM) for N-acetylation of glyphosate was discovered in several strains of Bacillus licheniformis (Weigmann) Chester by screening a microbial collection with a mass spectrometric assay. The parental enzyme confe...

To investigate the response of nine turfgrass species exposed to increasing rates of glyphosate application, the dry matter production, visual leaf injury symptoms (e.g., chlorosis and necrosis) and the concentrations of shikimate and mineral nutrients were determined in shoots. The rates of foliar glyphosate application were 0%, 5% (1.58 mM), and 20% (6.32 mM) of the recommended application ra...

A gene has been introduced into soybeans to confer tolerance to glyphosate, the active ingredient in the herbicide, Roundup (Monsanto Co., St. Louis, Mo.) 1,2 Soybean varieties expressing this trait will enable farmers to use Roundup herbicide within the crop during the growing season. Previous studies have confirmed the safety of the introduced protein (5-enolpyruvylshikimate-3-phosphate synth...

INTRODUCTION Canola, which is genetically modified (GM) for tolerance to glyphosate, has the potential to become established as a new glyphosate resistant weed, thus reducing the effectiveness of glyphosate. METHODS Volunteer from dormant canola seeds produced thousands of plants per hectare in the fourth year (2011) following a 2007 crop harvest. This occurred with no additional canola seed ...

As glyphosate is a broad spectrum herbicide extensively used in agriculture worldwide, identification of new aroA genes with high level of glyphosate tolerance is essential for the development and breeding of transgenic glyphosate-tolerant crops. In this study, an aroA gene was cloned from a Janibacter sp. strain isolated from marine sediment (designated as aroAJ. sp). The purified aroAJ. sp en...