Evolution of Glyphosate-Resistant Crop Technology

Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 108-117 ◽  
Author(s):  
Jerry M. Green

New and improved glyphosate-resistant (GR) crops continue to be rapidly developed. These crops confer greater crop safety to multiple glyphosate applications, higher rates, and wider application timings. Many of these crops will also have glyphosate resistance stacked with traits that confer resistance to herbicides with other modes of actions to expand the utility of existing herbicides and to increase the number of mixture options that can delay the evolution of GR weeds. Some breeding stacks of herbicide resistance traits are currently available, but the trend in the future will be to combine resistance genes in molecular stacks. The first example of such a molecular stack has a new metabolically based mechanism to inactivate glyphosate combined with an active site-based resistance for herbicides that inhibit acetolactate synthase (ALS). This stack confers resistance to glyphosate and all five classes of ALS-inhibiting herbicides. Other molecular stacks will include glyphosate resistance with resistance to auxin herbicides and herbicides that inhibit acetyl coenzyme A carboxylase (ACCase) and 4-hydroxyphenyl pyruvate dioxygenase (HPPD). Scientists are also studying a number of other herbicide resistance transgenes. Some of these new transgenes will be used to make new multiple herbicide-resistant crops that offer growers more herbicide options to meet their changing weed management needs and to help sustain the efficacy of glyphosate.

Weed Science ◽  
2019 ◽  
Vol 67 (6) ◽  
pp. 605-612 ◽  
Author(s):  
Xiangying Liu ◽  
Shihai Xiang ◽  
Tao Zong ◽  
Guolan Ma ◽  
Lamei Wu ◽  
...  

AbstractThe widespread, rapid evolution of herbicide-resistant weeds is a serious and escalating agronomic problem worldwide. During China’s economic boom, the country became one of the most important herbicide producers and consumers in the world, and herbicide resistance has dramatically increased in the past decade and has become a serious threat to agriculture. Here, following an evidence-based PRISMA (preferred reporting items for systematic reviews and meta-analyses) approach, we carried out a systematic review to quantitatively assess herbicide resistance in China. Multiple weed species, including 26, 18, 11, 9, 5, 5, 4, and 3 species in rice (Oryza sativa L.), wheat (Triticum aestivum L.), soybean [Glycine max (L.) Merr.], corn (Zea mays L.), canola (Brassica napus L.), cotton (Gossypium hirsutum L.)., orchards, and peanut (Arachis hypogaea L.) fields, respectively, have developed herbicide resistance. Acetolactate synthase inhibitors, acetyl-CoA carboxylase inhibitors, and synthetic auxin herbicides are the most resistance-prone herbicides and are the most frequently used mechanisms of action, followed by 5-enolpyruvylshikimate-3-phosphate synthase inhibitors and protoporphyrinogen oxidase inhibitors. The lack of alternative herbicides to manage weeds that exhibit cross-resistance or multiple resistance (or both) is an emerging issue and poses one of the greatest threats challenging the crop production and food safety both in China and globally.


2012 ◽  
Vol 26 (3) ◽  
pp. 391-398 ◽  
Author(s):  
Peter Boutsalis ◽  
Gurjeet S. Gill ◽  
Christopher Preston

Herbicide resistance in rigid ryegrass is an escalating problem in grain-cropping fields of southeastern Australia due to increased reliance on herbicides as the main method for weed control. Weed surveys were conducted between 1998 and 2009 to identify the extent of herbicide-resistant rigid ryegrass across this region to dinitroaniline, and acetolactate synthase- and acetyl coenzyme A (CoA) carboxylase-inhibiting herbicides. Rigid ryegrass was collected from cropped fields chosen at random. Outdoor pot studies were conducted during the normal winter growing season for rigid ryegrass with PRE-applied trifluralin and POST-applied diclofop-methyl, chlorsulfuron, tralkoxydim, pinoxaden, and clethodim. Herbicide resistance to trifluralin in rigid ryegrass was identified in one-third of the fields surveyed from South Australia, whereas less than 5% of fields in Victoria exhibited resistance. In contrast, resistance to chlorsulfuron was detected in at least half of the cropped fields across southeastern Australia. Resistance to the cereal-selective aryloxyphenoxypropionate-inhibiting herbicides diclofop-methyl, tralkoxydim, and pinoxaden ranged between 30 and 60% in most regions, whereas in marginal cropping areas less than 12% of fields exhibited resistance. Resistance to clethodim varied between 0 and 61%. Higher levels of resistance to clethodim were identified in the more intensively cropped, higher-rainfall districts where pulse and canola crops are common. These weed surveys demonstrated that a high incidence of resistance to most tested herbicides was present in rigid ryegrass from cropped fields in southeastern Australia, which presents a major challenge for crop producers.


Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2248
Author(s):  
Javid Gherekhloo ◽  
Saeid Hassanpour-bourkheili ◽  
Parvin Hejazirad ◽  
Sajedeh Golmohammadzadeh ◽  
Jose G. Vazquez-Garcia ◽  
...  

Weeds, such as Phalaris spp., can drastically reduce the yield of crops, and the evolution of resistance to herbicides has further exacerbated this issue. Thus far, 23 cases of herbicide resistance in 11 countries have been reported in Phalaris spp., including Phalaris minor Retz., Phalaris paradoxa L., and Phalaris brachystachys L., for photosystem II (PS-II), acetyl-CoA carboxylase (ACCase), and acetolactate synthase (ALS)-inhibiting herbicides. This paper will first review the cases of herbicide resistance reported in P. minor, P. paradoxa, and P. brachystachys. Then, the mechanisms of resistance in Phalaris spp. are discussed in detail. Finally, the fitness cost of herbicide resistance and the literature on the management of herbicide-resistant weeds from these species are reviewed.


2016 ◽  
Vol 56 (4) ◽  
pp. 402-410 ◽  
Author(s):  
Kazimierz Adamczewski ◽  
Roman Kierzek ◽  
Kinga Matysiak

AbstractAlopecurus myosuroides seeds were sampled from 32 winter wheat fields from 2010 to 2014. Resistance to herbicides was detected in 17 A. myosuroides populations. In addition to single resistance to herbicides, cross-resistance and multiple resistance to acetolactate synthase (ALS)- and acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides were found. Application of sulfometuron and imazapyr was unable to control some of the resistant biotypes in this study. This result implies that resistance in these populations is due to a target site mechanism. The A. myosuroides biotypes resistant to ACCase-inhibiting herbicides varied in their responses to derivatives of aryloxy-phenoxy-propionic acid (FOPs), cyclohexanediones (DIMs) and phenylpyrazolines (DENs). Resistant biotypes of A. myosuroides that could not be controlled with fenoxaprop-P-ethyl (FOP) and pinoxaden (DEN) were controlled with clethodim (DIM).


Weed Science ◽  
2014 ◽  
Vol 62 (2) ◽  
pp. 427-431 ◽  
Author(s):  
Dale L. Shaner

The selection of herbicide-resistant weed populations began with the introduction of synthetic herbicides in the late 1940s. For the first 20 years after introduction, there were limited reported cases of herbicide-resistant weeds. This changed in 1968 with the discovery of triazine-resistant common groundsel. Over the next 15 yr, the cases of herbicide-resistant weeds increased, primarily to triazine herbicides. Although triazine resistance was widespread, the resistant biotypes were highly unfit and were easily controlled with specific alternative herbicides. Weed scientists presumed that this would be the case for future herbicide-resistant cases and thus there was not much concern, although the companies affected by triazine resistance were somewhat active in trying to detect and manage resistance. It was not until the late 1980s with the discovery of resistance to Acetyl Co-A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors that herbicide resistance attracted much more attention, particularly from industry. The rapid evolution of resistance to these classes of herbicides affected many companies, who responded by first establishing working groups to address resistance to specific classes of herbicides, and then by formation of the Herbicide Resistance Action Committee (HRAC). The goal of these groups, in cooperation with academia and governmental agencies, was to act as a forum for the exchange of information on herbicide-resistance selection and to develop guidelines for managing resistance. Despite these efforts, herbicide resistance continued to increase. The introduction of glyphosate-resistant crops in the 1995 provided a brief respite from herbicide resistance, and farmers rapidly adopted this relatively simple and reliable weed management system based on glyphosate. There were many warnings from academia and some companies that the glyphosate-resistant crop system was not sustainable, but this advice was not heeded. The selection of glyphosate resistant weeds dramatically changed weed management and renewed emphasis on herbicide resistance management. To date, the lesson learned from our experience with herbicide resistance is that no herbicide is invulnerable to selecting for resistant biotypes, and that over-reliance on a weed management system based solely on herbicides is not sustainable. Hopefully we have learned that a diverse weed management program that combines multiple methods is the only system that will work for the long term.


Weed Science ◽  
2021 ◽  
pp. 1-25
Author(s):  
Qian Yang ◽  
Xia Yang ◽  
Zichang Zhang ◽  
Jieping Wang ◽  
Weiguo Fu ◽  
...  

Abstract Barnyardgrass (Echinochloa crus-galli) is a noxious grass weed which infests rice fields and causes huge crop yield losses. In this study, we collected twelve E. crus-galli populations from rice fields of Ningxia province in China and investigated the resistance levels to acetolactate synthase (ALS) inhibitor penoxsulam and acetyl-CoA carboxylase (ACCase) inhibitor cyhalofop-butyl. The results showed that eight populations exhibited resistance to penoxsulam and four populations evolved resistance to cyhalofop-butyl. Moreover, all of the four cyhalofop-butyl-resistant populations (NX3, NX4, NX6 and NX7) displayed multiple-herbicide-resistance (MHR) to both penoxsulam and cyhalofop-butyl. The alternative herbicides bispyribac-sodium, metamifop and fenoxaprop-P-ethyl cannot effectively control the MHR plants. To characterize the molecular mechanisms of resistance, we amplified and sequenced the target-site encoding genes in resistant and susceptible populations. Partial sequences of three ALS genes and six ACCase genes were examined. A Trp-574-Leu mutation was detected in EcALS1 and EcALS3 in two high-level (65.84- and 59.30-fold) penoxsulam-resistant populations NX2 and NX10, respectively. In addition, one copy (EcACC4) of ACCase genes encodes a truncated aberrant protein due to a frameshift mutation in E. crus-galli populations. None of amino acid substitutions that are known to confer herbicide resistance were detected in ALS and ACCase genes of MHR populations. Our study reveals the widespread of multiple-herbicide resistant E. crus-galli populations at Ningxia province of China that exhibit resistance to several ALS and ACCase inhibitors. Non-target-site based mechanisms are likely to be involved in E. crus-galli resistance to the herbicides, at least in four MHR populations.


Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Jéssica F. L. Leal ◽  
Amanda dos S. Souza ◽  
Junior Borella ◽  
André Lucas S. Araujo ◽  
Ana Claudia Langaro ◽  
...  

Abstract Herbicide-resistant weed management is one of the greatest agricultural challenges in crop production. Thus, the quick identification of resistant-herbicide weeds is extremely important for management. This study aimed to evaluate resistance to PSI-inhibitor herbicides (diquat) of Sumatran Fleabane [(Erigeron sumatrensis (Retz.) E.Walker)] and physiological response to paraquat application. The research was conducted with two E. sumatrensis biotypes, one susceptible and the other with multiple resistance to herbicides from five different modes of action (glyphosate, paraquat, diuron, saflufenacil, and 2,4-D). A dose-response assay was carried out to evaluate herbicide resistance to diquat in paraquat-resistant E. sumatrensis biotype. The enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), hydrogen peroxide (H2O2) content, and chlorophyll a fluorescence were measured in both biotypes after paraquat (400 g ai ha−1) application. The dose-response assay confirmed resistance of E. sumatrensis to diquat with resistance factor levels of 26-fold and 6-fold for LD50 and GR50 values, respectively, compared with the susceptible biotype. The accumulation of H2O2 occurred faster in the paraquat-susceptible biotype than in the resistant ones. Paraquat treatment caused an increase in SOD and APX activity in the susceptible biotype, but antioxidant enzyme activities were unaffected by paraquat in the resistant one at 5 hours after application (HAA). Chlorophyll a fluorescence increased along the first 4 HAA in both resistant and susceptible biotypes. However, at 24 HAA the resistant biotype showed a decline in fluorescence close to untreated plants while susceptible one died, which can be used to diagnose paraquat resistance at 24 HAA. There is confirmed resistance to diquat in a paraquat-resistant E. sumatrensis biotype. The paraquat-resistant biotype does not induce antioxidative enzymes, as a possible mechanism of resistance to paraquat, but shows a fast recovery of photosynthesis and continuous growth when subjected to paraquat, while the paraquat-susceptible biotype does not survive.


Weed Science ◽  
2016 ◽  
Vol 64 (SP1) ◽  
pp. 641-648 ◽  
Author(s):  
Claudio Rubione ◽  
Sarah M. Ward

The evolution of herbicide-resistant weeds is a major concern in the corn- and soybean-producing Pampas region of Argentina, where growers predominantly plant glyphosate-resistant crop varieties and depend heavily on glyphosate for weed control. Currently, 16 weed species in Argentina are resistant to one or more of three different herbicide mechanisms of action, and resistant weed populations continue to increase, posing a serious threat to agricultural production. Implementation of integrated weed management to address herbicide resistance faces significant barriers in Argentina, especially current land ownership and rental patterns in the Pampas. More than 60% of Pampas cropland is rented to tenants for periods that rarely exceed 1 yr, resulting in crop rotation being largely abandoned, and crop export taxes and quotas have further discouraged wheat and corn production in favor of continuous soybean production. In this paper we discuss ways to facilitate new approaches to weed management in Argentina, including legal and economic reforms and the formation of a national committee of stakeholders from public and private agricultural sectors.


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