A Decade of Glyphosate-ResistantLoliumaround the World: Mechanisms, Genes, Fitness, and Agronomic Management

Weed Science ◽  
2009 ◽  
Vol 57 (4) ◽  
pp. 435-441 ◽  
Author(s):  
Christopher Preston ◽  
Angela M. Wakelin ◽  
Fleur C. Dolman ◽  
Yazid Bostamam ◽  
Peter Boutsalis

Glyphosate resistance was first discovered in populations of rigid ryegrass in Australia in 1996. Since then, glyphosate resistance has been detected in additional populations of rigid ryegrass and Italian ryegrass in several other countries. Glyphosate-resistant rigid ryegrass and Italian ryegrass have been selected in situations where there is an overreliance on glyphosate to the exclusion of other weed control tactics. Two major mechanisms of glyphosate resistance have been discovered in these two species: a change in the pattern of glyphosate translocation such that glyphosate accumulates in the leaf tips of resistant plants instead of in the shoot meristem; and amino acid substitutions at Pro 106 within the target site, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). There are also populations with both mechanisms. In the case of glyphosate resistance, the target site mutations tend to provide a lower level of resistance than does the altered translocation mechanism. Each of these resistance mechanisms is inherited as a single gene trait that is largely dominant. As these ryegrass species are obligate outcrossers, this ensures resistance alleles can move in both pollen and seed. Some glyphosate-resistant rigid ryegrass populations appear to have a significant fitness penalty associated with the resistance allele. Field surveys show that strategies vary in their ability to reduce the frequency of glyphosate resistance in populations and weed population size, with integrated strategies—including alternative weed management and controlling seed set of surviving plants—the most effective.

2006 ◽  
Vol 20 (2) ◽  
pp. 282-289 ◽  
Author(s):  
Stephen B. Powles ◽  
Christopher Preston

Resistance to the herbicide glyphosate is currently known in at least eight weed species from many countries. Some populations of goosegrass from Malaysia, rigid ryegrass from Australia, and Italian ryegrass from Chile exhibit target site–based resistance to glyphosate through changes at amino acid 106 of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene. Mutations change amino acid 106 from proline to either serine or threonine, conferring an EPSPS weakly resistant to glyphosate. The moderate level of resistance is sufficient for commercial failure of the herbicide to control these plants in the field. Conversely, a nontarget site resistance mechanism has been documented in glyphosate-resistant populations of horseweed and rigid ryegrass from the United States and Australia, respectively. In these resistant plants, there is reduced translocation of glyphosate to meristematic tissues. Both of these mechanisms are inherited as a single, nuclear gene trait. Although at present only two glyphosate-resistance mechanisms are known, it is likely that other mechanisms will become evident. The already very large and still increasing reliance on glyphosate in many parts of the world will inevitably result in more glyphosate-resistant weeds, placing the sustainability of this precious herbicide resource at risk.


Weed Science ◽  
2012 ◽  
Vol 60 (3) ◽  
pp. 474-479 ◽  
Author(s):  
Yazid Bostamam ◽  
Jenna M. Malone ◽  
Fleur C. Dolman ◽  
Peter Boutsalis ◽  
Christopher Preston

Glyphosate is widely used for weed control in the grape growing industry in southern Australia. The intensive use of glyphosate in this industry has resulted in the evolution of glyphosate resistance in rigid ryegrass. Two populations of rigid ryegrass from vineyards, SLR80 and SLR88, had 6- to 11-fold resistance to glyphosate in dose-response studies. These resistance levels were higher than two previously well-characterized glyphosate-resistant populations of rigid ryegrass (SLR77 and NLR70), containing a modified target site or reduced translocation, respectively. Populations SLR80 and SLR88 accumulated less glyphosate, 12 and 17% of absorbed glyphosate, in the shoot in the resistant populations compared with 26% in the susceptible population. In addition, a mutation within the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) where Pro106had been substituted by either serine or threonine was identified. These two populations are more highly resistant to glyphosate as a consequence of expressing two different resistance mechanisms concurrently.


2021 ◽  
Vol 63 (2) ◽  
pp. 74-80
Author(s):  
The Duc Ngo ◽  

Glyphosate has become the most widely used herbicide worldwide since 1974 with a global use of 8.6 billion kg (glyphosate active ingredient) between 1974 and 2014. This study reports on glyphosate resistant (GR) weeds and their resistance mechanisms based on global scientifically reported cases. Forty-nine different weed species have evolved resistance to glyphosate in 29 countries with a total of 318 identified cases worldwide. Fifty percent of these resistance cases were found in glyphosate-resistant cropping systems. There were 255 identified cases (80.2%) of glyphosate resistance in the top five countries (in terms of number of cases and species), namely USA, Australia, Argentina, Brazil, and Canada. The five most popular weed species (in terms of number of cases) found to be resistant to glyphosate were Conyza canadensis, Amaranthus palmeri, Amaranthus tuberculatus, Lolium perenne ssp. Multiflorum,and Ambrosia artemisiifolia with 42, 42, 29, 26, and 21 reported cases, respectively. Out of 49 weed species, 19 GR weed species were found to not only be resistant to glyphosate but also to other herbicide sites of action (multiple herbicide resistance). Glyphosate resistance mechanisms in weeds include (1) target-site alterations: target-site mutation and target-site gene amplification; and (2) non-target-site mechanisms involving different modes of exclusion from the target site: reduced glyphosate uptake, reduced glyphosate translocation, and enhanced glyphosate metabolism. It is essential to have an integrated weed management program that includes not only smart herbicide mixtures and rotations, but also cultural, manual, mechanical, and crop-based weed management methods.


Weed Science ◽  
2010 ◽  
Vol 58 (2) ◽  
pp. 109-117 ◽  
Author(s):  
Joshua S. Yuan ◽  
Laura L. G. Abercrombie ◽  
Yongwei Cao ◽  
Matthew D. Halfhill ◽  
Xin Zhou ◽  
...  

The evolution of glyphosate resistance in weedy species places an environmentally benign herbicide in peril. The first report of a dicot plant with evolved glyphosate resistance was horseweed, which occurred in 2001. Since then, several species have evolved glyphosate resistance and genomic information about nontarget resistance mechanisms in any of them ranges from none to little. Here, we report a study combining iGentifier transcriptome analysis, cDNA sequencing, and a heterologous microarray analysis to explore potential molecular and transcriptomic mechanisms of nontarget glyphosate resistance of horseweed. The results indicate that similar molecular mechanisms might exist for nontarget herbicide resistance across multiple resistant plants from different locations, even though resistance among these resistant plants likely evolved independently and available evidence suggests resistance has evolved at least four separate times. In addition, both the microarray and sequence analyses identified non–target-site resistance candidate genes for follow-on functional genomics analysis.


2018 ◽  
Vol 18 (3) ◽  
pp. 127-135 ◽  
Author(s):  
Kohei Kurata ◽  
Yuki Niinomi ◽  
Yoshiko Shimono ◽  
Masahiro Miyashita ◽  
Tohru Tominaga

Weed Science ◽  
2009 ◽  
Vol 57 (6) ◽  
pp. 567-573 ◽  
Author(s):  
Chad E. Brewer ◽  
Lawrence R. Oliver

Greenhouse studies were established in Fayetteville, AR, to investigate glyphosate resistance in Arkansas common ragweed populations. Common ragweed seed were collected from plants in Pope and Jackson counties in Arkansas. Plants grown from seed were sprayed with one of seven glyphosate rates. Populations in Pope and Jackson counties were 21-fold and 10-fold more tolerant to glyphosate, respectively, than a known susceptible population. Based on14C-glyphosate absorption and translocation studies, reduced glyphosate absorption or translocation was not the resistance mechanism in Arkansas glyphosate-resistant common ragweed. Shikimate accumulation did not differ among the known susceptible and the two resistant populations at 3 d after treatment (DAT). However, by 5 DAT, shikimate accumulation in the two resistant populations was lower than the known susceptible population. Data indicate that glyphosate-resistant common ragweed is present in at least two locations in Arkansas, and the resistance mechanism is not an insensitive target site or reduced glyphosate absorption or translocation.


Weed Science ◽  
2006 ◽  
Vol 54 (02) ◽  
pp. 212-219 ◽  
Author(s):  
Angela M. Wakelin ◽  
Christopher Preston

In Australia, glyphosate resistance has been observed in rigid ryegrass in several states including New South Wales (NSW) and South Australia (SA). Several populations of glyphosate-resistant rigid ryegrass were analyzed for the inheritance of glyphosate resistance. Eight glyphosate-resistant populations were crossed to the same susceptible population to create first filial generation (F1) families. Individuals from the F1families were subsequently treated with glyphosate. The response to glyphosate of F1families from all eight crosses was more similar to the resistant parent than the susceptible parent. Within crosses, dose responses of reciprocal F1families were not significantly different from each other, indicating glyphosate resistance is encoded on the nuclear genome in all eight populations. The level of dominance observed in dose–response experiments ranged from partial to total within the herbicide doses tested. F1individuals from five of the populations were crossed with susceptible (S) individuals to create backcross (BC) populations. Most of the families from these BC populations segregated in a manner consistent with a single gene controlling glyphosate resistance. These results indicate that resistance is inherited as a single dominant allele in four out of the five glyphosate-resistant rigid ryegrass populations. Such information is vital in the development of management strategies for glyphosate resistance in Australia.


2017 ◽  
Vol 17 (2) ◽  
pp. 84-90 ◽  
Author(s):  
Valentina Dwi Suci Handayani ◽  
Yuki Tanno ◽  
Masayuki Yamashita ◽  
Hiroyuki Tobina ◽  
Minoru Ichihara ◽  
...  

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1970
Author(s):  
José Alfredo Domínguez-Valenzuela ◽  
Ricardo Alcántara-de la Cruz ◽  
Candelario Palma-Bautista ◽  
José Guadalupe Vázquez-García ◽  
Hugo E. Cruz-Hipolito ◽  
...  

Of the six-glyphosate resistant weed species reported in Mexico, five were found in citrus groves. Here, the glyphosate susceptibility level and resistance mechanisms were evaluated in saltmarsh aster (Aster squamatus), a weed that also occurs in Mexican citrus groves. The R population accumulated 4.5-fold less shikimic acid than S population. S plants hardly survived at 125 g ae ha−1 while most of the R plants that were treated with 1000 g ae ha−1, which suffered a strong growth arrest, showed a vigorous regrowth from the third week after treatment. Further, 5-enolpyruvylshikimate-3-phosphate basal and enzymatic activities did not diverge between populations, suggesting the absence of target-site resistance mechanisms. At 96 h after treatment, R plants absorbed ~18% less glyphosate and maintained 63% of the 14C-glyphsoate absorbed in the treated leaf in comparison to S plants. R plants metabolized twice as much (72%) glyphosate to amino methyl phosphonic acid and glyoxylate as the S plants. Three non-target mechanisms, reduced absorption and translocation and increased metabolism, confer glyphosate resistance saltmarsh aster. This is the first case of glyphosate resistance recorded for A. squamatus in the world.


2021 ◽  
Vol 12 ◽  
Author(s):  
José G. Vázquez-García ◽  
Antonia M. Rojano-Delgado ◽  
Ricardo Alcántara-de la Cruz ◽  
Joel Torra ◽  
Ignacio Dellaferrera ◽  
...  

The levels of resistance to glyphosate of 13 barnyard grass (Echinochloa crus-galli) populations harvested across different agriculture areas in the Southern Iberian Peninsula were determined in greenhouse and laboratory experiments. Shikimate accumulation fast screening separated the populations regarding resistance to glyphosate: susceptible (S) E2, E3, E4, and E6 and resistant (R) E1, E5, E7, E8, E9, E10, E11, E12, and E13. However, resistance factor (GR50 E1–E13/GR50 E6) values separated these populations into three groups: (S) E2, E3, E4, and E6, (R) E1, E5, E7, E8, and E9, and very resistant (VR) E10, E11, E12, and E13. 14C-glyphosate assays performed on two S populations (E2 and E6) showed greater absorption and translocation than those found for R (E7 and E9) and VR (E10 and E12) populations. No previous population metabolized glyphosate to amino methyl phosphonic acid (AMPA) and glyoxylate, except for the E10 population that metabolized 51% to non-toxic products. The VR populations showed two times more 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity without herbicide than the rest, while the inhibition of the EPSPS activity by 50% (I50) required much higher glyphosate in R and VR populations than in S populations. These results indicated that different target-site and non-target-site resistance mechanisms were implicated in the resistance to glyphosate in E. crus-galli. Our results conclude that resistance is independent of climate, type of crop, and geographic region and that the level of glyphosate resistance was mainly due to the selection pressure made by the herbicide on the different populations of E. crus-galli studied.


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