2018
Volume 18, Number 2, pp. 78–93
Evolution of glyphosate resistance: is the rhizosphere microbiome a key factor?
Marek Cuhra
Institute of Marine Research, Bergen, Norway
Glyphosate herbicides are applied in large quantities in global industrial agriculture and have led to the increasing occurrence of glyphosate-resistant species of non-agricultural plants, which invade farm fields as agricultural pests (weeds). Despite decades of intensive research effort aimed at explaining, preventing and remediating this damage imposed upon modern industrial agriculture, several fundamental scientific questions remain unanswered. The adaptability of soil (rhizospheral) microörganisms towards xenobiotics such as herbicides is rapid due to biological and ecological factors, notably high genetic variability, mutability, short generation time and high numbers of individuals. Advantageous genes thus developed and subjectively perceived as attractive may be mediated via horizontal gene transfer. Here, a new scientific approach is introduced, presenting observations, theoretical explanations and testable hypotheses. Concern is raised regarding possible detrimental effects of the present intensive use of glyphosate herbicides, the selective pressure such toxins exert on microbial communities in soils, and the subsequent potential adverse effects of the wide occurrence of mobile genes enabling tolerance or resistance in other organisms. A theoretical approach to specific ecological consequences of industrial farming is presented and mechanistic explanations are proposed as specific hypotheses, which can be tested experimentally.
Keywords: agroecology, agroindustry, biotechnology, glyphosate-resistant weed, horizontal gene transfer, pesticide dependence, rhizosphere microbiome