Physiological and molecular insight on the mechanisms of resistance to glyphosate in Conyza canadensis (L.) Cronq. biotypes

Dinelli, Giovanni; Marotti, Ilaria; Bonetti, Alessandra; Minelli, Maurizio; Catizone, Pietro; Barnes, J. E.

doi:10.1016/j.pestbp.2006.01.004

Cited by 117 publications

(167 citation statements)

References 29 publications

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“…Anyway, our results suggest that glyphosate metabolism is not involved or plays a minor role in the resistance of the L. rigidum biotype we studied because glyoxylate accumulation in the susceptible L. rigidum population did not match a corresponding glyphosate metabolism. The same was reported in C. canadensis from USA (Dinelli et al 2006). …”

Section: Glyphosate Metabolismsupporting

confidence: 83%

First case of glyphosate resistance in France

Fernández

Gauvrit

Barro

et al. 2015

Agron. Sustain. Dev.

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Glyphosate is a broad-spectrum systemic herbicide used to kill weeds, especially annual broadleaf weeds and grasses known to compete with commercial crops grown around the globe. However, weeds evolve and develop resistance to glyphosate. Until recently, no case of glyphosate resistance had been detected in France. Glyphosate resistance was indeed recently recorded in a Lolium rigidum weed population from a vineyard in the South of France. Here, we studied the mechanisms of this resistance case. Seed samples of L. rigidum were collected from the vineyard where resistance had been detected, as well as from a nearby area that had no known history of exposure to glyphosate. We studied the effect of retention of glyphosate spray, shikimic acid accumulation, glyphosate absorption and translocation, glyphosate metabolism, and the sequence of the enzyme that glyphosate targets in plants, 5-enolpyruvylshikimate-3-phosphate synthase. Our results show that glyphosate absorption decreased by 30 % in the resistant L. rigidum weed. In addition, glyphosate translocation out of the treated leaves was reduced by 52 %. Finally, the resistant biotype had a serine amino acid substitution at position 106 of the predicted protein, instead of the proline amino acid present in the susceptible population. Our results suggest that the resistant population of L. rigidum presents three different mechanisms of resistance to glyphosate, namely reduced absorption, reduced mobility in the plants, and a mutation in the gene coding for the enzyme targeted by glyphosate.

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Section: Glyphosate Metabolismsupporting

confidence: 83%

First case of glyphosate resistance in France

Fernández

Gauvrit

Barro

et al. 2015

Agron. Sustain. Dev.

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“…However, the elevated expression was not due to gene amplification because EPSPS gene copy number in L. rigidum was examined using DNA blot hybridizations and glyphosate-resistant lines did not have increased EPSPS gene copy number in comparison with glyphosate-susceptible lines. In glyphosate-resistant biotypes of C. canadensis and C. bonariensis, basal EPSPS mRNA levels were double the levels in susceptible biotypes, but the resistant biotypes also had reduced glyphosate translocation (32,33).…”

Section: Discussionmentioning

confidence: 93%

Gene amplification confers glyphosate resistance in Amaranthus palmeri

Gaines

Zhang

Wang

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

603

868

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The herbicide glyphosate became widely used in the United States and other parts of the world after the commercialization of glyphosate-resistant crops. These crops have constitutive overexpression of a glyphosate-insensitive form of the herbicide target site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Increased use of glyphosate over multiple years imposes selective genetic pressure on weed populations. We investigated recently discovered glyphosate-resistant Amaranthus palmeri populations from Georgia, in comparison with normally sensitive populations. EPSPS enzyme activity from resistant and susceptible plants was equally inhibited by glyphosate, which led us to use quantitative PCR to measure relative copy numbers of the EPSPS gene. Genomes of resistant plants contained from 5-fold to more than 160-fold more copies of the EPSPS gene than did genomes of susceptible plants. Quantitative RT-PCR on cDNA revealed that EPSPS expression was positively correlated with genomic EPSPS relative copy number. Immunoblot analyses showed that increased EPSPS protein level also correlated with EPSPS genomic copy number. EPSPS gene amplification was heritable, correlated with resistance in pseudo-F 2 populations, and is proposed to be the molecular basis of glyphosate resistance. FISH revealed that EPSPS genes were present on every chromosome and, therefore, gene amplification was likely not caused by unequal chromosome crossing over. This occurrence of gene amplification as an herbicide resistance mechanism in a naturally occurring weed population is particularly significant because it could threaten the sustainable use of glyphosate-resistant crop technology.5-enolpyruvylshikimate-3-phosphate synthase | herbicide resistance | mobile genetic element | evolution | Palmer amaranth

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“…Elongation, roundness and compactness are indicators of the circularity of the seed. Seeds with shape closer to a perfect circle present values of elongation, roundness and compactness closer to one [24]. The morphological features (colour, structural characteristics and related ratios) are mean values of parameters extracted from both side images of seed.…”

Section: Seed Morphology and Weightmentioning

confidence: 99%

Germination ecology of Ambrosia artemisiifolia L. and Ambrosia trifida L. biotypes suspected of glyphosate resistance

et al. 2013

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The germination ecology of Ambrosia artemisiifolia and A. trifida glyphosate susceptible biotypes sampled in marginal areas, was compared with that of the same species but different biotypes suspected of glyphosate resistance, common and giant ragweed, respectively. The suspected resistant biotypes were sampled in Roundup Ready® soybean fields. Within each weed species, the seeds of the biotype sampled in marginal area were significantly bigger and heavier than those of the biotype sampled in the soybean fields. A. artemisiifolia biotypes exhibited a similar dormancy and germination, while differences between A. trifida biotypes were observed. A. artemisiifolia biotypes showed similar threshold temperature for germination, whereas, the threshold temperature of the susceptible A. trifida biotype was half as compared to that of the resistant A. trifida biotype. No significant differences in emergence as a function of sowing depth were observed between susceptible A. artemisiifolia and suspected resistant A. trifida biotype, while at a six-cm seedling depth the emergence of the A. artemisiifolia susceptible biotype was 2.5 times higher than that of the A. trifida suspected resistant biotype. This study identified important differences in seed germination between herbicide resistant and susceptible biotypes and relates this information to the ecology of species adapted to Roundup Ready® fields. Information obtained in this study supports sustainable management strategies, with continued use of glyphosate as a possibility.

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Physiological and molecular insight on the mechanisms of resistance to glyphosate in Conyza canadensis (L.) Cronq. biotypes

Cited by 117 publications

References 29 publications

First case of glyphosate resistance in France

First case of glyphosate resistance in France

Gene amplification confers glyphosate resistance in Amaranthus palmeri

Germination ecology of Ambrosia artemisiifolia L. and Ambrosia trifida L. biotypes suspected of glyphosate resistance

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