A holistic approach in herbicide resistance research and management: from resistance detection to sustainable weed control

Chun Liu,Eddie Mcindoe,Lucy V Jackson,Raul Moreno,Shiv S Kaundun,Daniel Tuesca,Sarah-Jane Hutchings

doi:10.1038/s41598-020-77649-z

Abstract

Agricultural weeds can adapt rapidly to human activities as exemplified by the evolution of resistance to herbicides. Despite its multi-faceted nature, herbicide resistance has rarely been researched in a holistic manner. A novel approach combining timely resistance confirmation, investigation of resistance mechanisms, alternative control solutions and population modelling was adopted for the sustainable management of the Amaranthus palmeri weed in soybean production systems in Argentina. Here, we show that resistance to glyphosate in the studied population from Cordoba province was mainly due to a P106S target-site mutation in the 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS) gene, with minor contributions from EPSPS gene duplication/overexpression. Alternative herbicides, such as fomesafen, effectively controlled the glyphosate-resistant plants. Model simulations revealed the tendency of a solo herbicidal input to primarily select for a single resistance mechanism and suggested that residual herbicides, alongside chemical diversity, were important for the sustainable use of these herbicides. We also discuss the value of an interdisciplinary approach for improved understanding of evolving weeds.

Highlights

Agricultural weeds can adapt rapidly to human activities as exemplified by the evolution of resistance to herbicides
This result was different to what is commonly found in the glyphosate-resistant A. palmeri populations in the USA which are predominantly characterised by gene duplication/overexpression[5,18,19]
Kaundun et al tested 115 A. palmeri populations from the Midwestern USA, and none of them contained the P106S mutation[6]. This reflects the use of different weed control practices in Argentina and the USA, recently, the P106S mutation was found in Conyza canadensis in the U SA20

Summary

Introduction

Agricultural weeds can adapt rapidly to human activities as exemplified by the evolution of resistance to herbicides. We show that resistance to glyphosate in the studied population from Cordoba province was mainly due to a P106S target-site mutation in the 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS) gene, with minor contributions from EPSPS gene duplication/overexpression Alternative herbicides, such as fomesafen, effectively controlled the glyphosate-resistant plants. The long-term sustainability of weed control practices becomes difficult to predict under laboratory or field settings due to the diverse nature of weeds, the complex resistance mechanism, and the interfering human activities, as well as the interactions among these factors. In this respect, computer-based population models are useful tools for the cost-effective prediction of the evolutionary dynamics of weed populations under different management programs. We have combined the different research aspects, from resistance detection to population modelling, and present a case study on the control of the highly damaging A. palmeri in soybean agroecosystems in Argentina

Methods

Results

Conclusion