Potential roles for microbial endophytes in herbicide tolerance in plants.
Herbicide tolerance in crops and weeds is considered to be monotrophic, i.e. determined by the relative susceptibility of the physiological process targeted and the plant's ability to metabolise and detoxify the agrochemical. A growing body of evidence now suggests that endophytes, microbes that inhabit plant tissues and provide a range of growth, health and defence enhancements, can contribute to other types of abiotic and biotic stress tolerance. The current evidence for herbicide tolerance being bitrophic, with both free-living and plant-associated endophytes contributing to tolerance in the host plant, has been reviewed. We propose that endophytes can directly contribute to herbicide detoxification through their ability to metabolise xenobiotics. In addition, we explore the paradigm that microbes can 'prime' resistance mechanisms in plants such that they enhance herbicide tolerance by inducing the host's stress responses to withstand the downstream toxicity caused by herbicides. This latter mechanism has the potential to contribute to the growth of non-target-site-based herbicide resistance in weeds. Microbial endophytes already contribute to herbicide detoxification in planta, and there is now significant scope to extend these interactions using synthetic biology approaches to engineer new chemical tolerance traits into crops via microbial engineering.
School of Agriculture, Food and Rural Development, Newcastle University, Newcastle, UK.
Catherine
http://orcid.org/0000-0001-7121-2236
C
Tétard-Jones
School of Agriculture, Food and Rural Development, Newcastle University, Newcastle, UK.
Robert
R
Edwards
D018556:Crops, Agricultural / Q000187:drug effects / Q000382:microbiology* / Q000502:physiology; D060026:Endophytes / Q000502:physiology*; D053209:Herbicide Resistance; D006540:Herbicides / Q000494:pharmacology; D010675:Pheromones / Q000494:pharmacology; D057685:Plant Weeds / Q000187:drug effects / Q000382:microbiology* / Q000502:physiology; D012988:Soil Microbiology; D013312:Stress, Physiological; D013559:Symbiosis; D015262:Xenobiotics / Q000494:pharmacology
D006540:Herbicides; D010675:Pheromones; D015262:Xenobiotics
allelochemicals; defence priming; herbicide selectivity; microbial symbiosis; multiple herbicide resistance; xenobiotics