Plant circadian rhythms regulate the effectiveness of a glyphosate-based herbicide

Abstract

Herbicides increase crop yields by allowing weed control and harvest management. Glyphosate is the most widely-used herbicide active ingredient, with $11 billion spent annually on glyphosate-containing products applied to >350 million hectares worldwide, using about 8.6 billion kg of glyphosate. The herbicidal effectiveness of glyphosate can depend upon the time of day of spraying. Here, we show that the plant circadian clock regulates the effectiveness of glyphosate. We identify a daily and circadian rhythm in the inhibition of plant development by glyphosate, due to interaction between glyphosate activity, the circadian oscillator and potentially auxin signalling. We identify that the circadian clock controls the timing and extent of glyphosate-induced plant cell death. Furthermore, the clock controls a rhythm in the minimum effective dose of glyphosate. We propose the concept of agricultural chronotherapy, similar in principle to chronotherapy in medical practice. Our findings provide a platform to refine agrochemical use and development, conferring future economic and environmental benefits.

Chemical Perturbation of Chloroplast-Related Processes Affects Circadian Rhythms of Gene Expression in Arabidopsis: Salicylic Acid Application Can Entrain the Clock

“…We also tested the hormone SA, norbornadiene (inhibitor of ethylene perception), diphenyleneiodonium (inhibitor of plasma membrane NADPH oxidases involved in hypersensitive reaction during pathogen recognition), butanedione monoxime (a ROS-inducing inhibitor of cytoplasmic streaming), and photosynthesis inhibitors DCMU [3-(3,4-dichlorophenyl)-1,1-dimethylurea] and DBMIB (2,5dibromo-3-methyl-6-isopropylbenzoquinone). This approach is similar to the chemical biology strategies previously used to investigate the Arabidopsis circadian clock (Toth et al, 2001;Belbin et al, 2019;Uehara et al, 2019).…”

Plant pharmacology: Insights into in-planta kinetic and dynamic processes of xenobiotics

“…There is a lack of comparative data between these methods and a need for standards and quality control of xylem sap measurements. Experiments need to take into consideration the rate of absorption, time of exposure, concentration dependence, circadian rhythm, pharmacodynamic response, effect of mixtures and plant health (Alberto et al, 2018;Belbin et al, 2019). Erroneous results and conclusions could be the result of any of these factors, and have caused misinterpretation and confusion in the field.…”

Understanding the chemistry of manganese fertilizers and glyphosate mixtures by using synchrotron X-ray spectrometry

“…Besides the introduction of transgenic crops, glyphosate's success is also due to its highly effective broad spectrum and low toxicity for animals [5], being also a very cheap herbicide [6]. Glyphosate is considered a once in a century herbicide [5], being the best-selling active ingredient for herbicides worldwide [7]. In 2018, more than 190 thousands of tons of glyphosate's active ingredient and its salts were sold within the Brazilian territory, four times more than the second best-selling herbicide, the 2,4-D [8,9].…”