Natural born weed killer?
Updated: Jun 3, 2020
Weeds can restrict plant growth, damage farming machinery, increase frost risk, and host a variety of pests. While natural weed killers are inexpensive and have long-term, far-reaching effects, weeds continue to develop resistance to common herbicides. Given that effective and safe weed control is vital in agriculture and health, this herbicide resistance is, without question, a significant problem.
But we’re not the only ones battling with weeds. Micro-organisms found in the soil must contend for space and nutrients; they can produce protective chemicals to kill nearby competitors while also maintaining immunity from these poisons via “self-resistance”. Researchers at UCLA have discovered and isolated the genes responsible for producing this natural weed killer. The article was published yesterday in Nature.
Using resistance gene-directed genome mining, the authors were able to identify the self-resistance genes responsible for the production of a compound that targets an enzyme vital for plant survival. Inhibition of this enzyme by the new herbicide disrupts an important metabolic pathway responsible for the production of essential amino acids. This kills the plants.
Yes, this compound can potentially kill not only weeds – the ‘undesirable’ plants – but also crops. However, the researchers have identified not only the herbicide, but also its exact target within the plant. This means that, should the product become commercially available, crops can be made resistant to the herbicide through genetic engineering.
At present, the only herbicide-tolerant crops grown in the U.S. are engineered to be tolerant to glyphosate, a common herbicide. Genetic engineering of crops to be resistant to herbicides began in the mid-90’s, at which time a major motivating factor was to reduce pesticide use. However, an article by Charles Benbrook, PhD, claims that the increase in the volume and number of herbicides required to combat glyphosate-resistent weeds has dwarfed the reduction in pesticide use. This new natural weed killer could indeed overcome the current, pressing issue of herbicide resistance, but will weeds also become resistant to this natural herbicide over time?