Mechanisms of Resistance to Glyphosate in a Ryegrass (Lolium Multiflorum) Biotype from Chile

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 435-440 ◽  
Author(s):  
Paola Michitte ◽  
Rafael De Prado ◽  
Nelson Espinoza ◽  
Juan Pedro Ruiz-Santaella ◽  
Christian Gauvrit
Keyword(s):  
Leaf Surface ◽  
Lolium Multiflorum ◽  
Glyphosate Resistance ◽  
Contact Angles ◽  
Italian Ryegrass ◽  
Foliar Uptake ◽  
Mechanisms Of Resistance ◽  
Abaxial Surface ◽  
Abaxial Leaf Surface ◽  
Target Enzyme

Glyphosate behavior was examined in Italian ryegrass plants from Chile that were sensitive (S) and resistant (R) to this herbicide. In order to explain the resistance to glyphosate, contact angles, spray retention, foliar uptake, herbicide translocation, and target enzyme activity were studied. Contact angles of glyphosate solutions at a field concentration were 40° to 45° on the abaxial surface of R leaves as compared to 70° on S. Glyphosate spray retention by R plants was 35% lower than by S plants. Glyphosate uptake by the abaxial leaf surface of R plants was about 40% lower than that of S plants. In addition, in the R plants more glyphosate migrated to the tip of the treated leaves. The target enzyme in R and S plants was sensitive to the herbicide. Based on these and previous results, it is concluded that resistance in this Italian ryegrass biotype results from lower spray retention, lower foliar uptake from the abaxial leaf surface, and altered translocation pattern. The decreases in spray retention and foliar uptake constitute new mechanisms of glyphosate resistance.

Glyphosate-Resistant Italian Ryegrass (Lolium multiflorum) in California: Distribution, Response to Glyphosate, and Molecular Evidence for an Altered Target Enzyme

Weed Science ◽  
2008 ◽  
Vol 56 (4) ◽  
pp. 496-502 ◽  
Author(s):  
Marie Jasieniuk ◽  
Riaz Ahmad ◽  
Anna M. Sherwood ◽  
Jeffrey L. Firestone ◽  
Alejandro Perez-Jones ◽  
...  
Keyword(s):  
Shikimic Acid ◽  
Lolium Multiflorum ◽  
Amino Acid Position ◽  
Glyphosate Resistance ◽  
Italian Ryegrass ◽  
Shoot Biomass ◽  
Molecular Evidence ◽  
Missense Mutations ◽  
Coding Region ◽  
Target Enzyme

Selection by herbicides has resulted in widespread evolution of herbicide resistance in agricultural weeds. In California, resistance to glyphosate was first confirmed in rigid ryegrass in 1998. Objectives of this study were to determine the current distribution and level of glyphosate resistance in Italian ryegrass, and to assess whether resistance could be due to an altered target site. Seeds were sampled from 118 populations and seedlings were treated with glyphosate at 866 g ae ha−1. Percentage of survivors ranged from 5 to 95% in 54 populations. All plants from 64 populations died. One susceptible (S) population, four putatively resistant (R) populations, and one S accession from Oregon were used for pot dose–response experiments, shikimic acid analyses, and DNA sequencing. Seedlings were treated with glyphosate at eight rates, ranging from 108 to 13,856 g ae ha−1. Shoot biomass was evaluated 3 wk after treatment and fit to a log-logistic regression equation. On the basis of GR50(herbicide rate required to reduce growth by 50%) values, seedlings from putatively R populations were roughly two to 15 times more resistant to glyphosate than S plants. Shikimic acid accumulation was similar in all plants before glyphosate treatment, but at 4 and 7 DAT, S plants from California and Oregon accumulated approximately two and three times more shikimic acid, respectively, than R plants. Sequencing of a cDNA fragment of the EPSPS coding region revealed two different codons, both of which encode proline at amino acid position 106 in S individuals. In contrast, all R plants sequenced exhibited missense mutations at site 106. Plants from one population revealed a mutation resulting in a proline to serine substitution. Plants from three R populations exhibited a mutation corresponding to replacement of proline with alanine. Our results indicate that glyphosate resistance is widespread in Italian ryegrass populations of California, and that resistance is likely due to an altered target enzyme.

scholarly journals Extracuticular Wax and Contact Angle Measurements on Wheat (Triticum Vulgare L.)

1967 ◽  
Vol 20 (3) ◽  
pp. 509 ◽  
Author(s):  
JH Troughton ◽  
DM Hall
Keyword(s):  
Contact Angle ◽  
Leaf Surface ◽  
Flag Leaf ◽  
Contact Angles ◽  
Abaxial Surface ◽  
Triticum Vulgare ◽  
Angle Measurements ◽  
Abaxial Leaf Surface ◽  
Contact Angle Measurements ◽  
Plant Grown

Extracuticular wax and contact angles on wheat were studied because of their influence on the retention of chemical sprays and on disease resistance. Wax formed extensive deposits on wheat, irrespective of variety, stage of growth, or part of the plant, and these deposits overlaid or projected from the cuticle as platelets and rodlets. Platelets covered the adaxial and abaxial leaf surfaces of seedlings and some mature plants, while a net of rodlets covered the ear, culm, sheath, and flag leaf abaxial surface. Rods were occasionally present on the abaxial surface of mature vegetative leaves. Wax influenced the advancing contact angle of water droplets on wheat. Contact angles were all high, i.e. greater than 130� and generally about 150�. The contact angle on the adaxial leaf surface was higher than on the abaxial leaf surface, except on glasshouse-grown reproductive plants, where there was no difference between the two sides. Seedlings had higher contact angles than mature plants, but there was no trend in contact angle with tissue age within a leaf or within a mature plant. The contact angle on the flag leaf of glasshouse-grown reproductive Aotea plants was 24� higher than on a similar plant grown in the field.

scholarly journals Strategies to manage the evolution of glyphosate resistance in New Zealand

2016 ◽  
Vol 69 ◽  
pp. 252-257 ◽  
Author(s):  
K.C. Harrington ◽  
T.K. James ◽  
M.D. Parker ◽  
H. Ghanizadeh
Keyword(s):  
New Zealand ◽  
Weed Control ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Lolium Multiflorum ◽  
Resistance Management ◽  
Glyphosate Resistance ◽  
Italian Ryegrass ◽  
Fruit Crops ◽  
Sustainable Farming

The first cases of weeds developing resistance to glyphosate within New Zealand have recently been reported and investigated Both perennial ryegrass (Lolium perenne) and Italian ryegrass (Lolium multiflorum) populations have become resistant to glyphosate in several Marlborough vineyards due to many years of weed control using mainly just glyphosate Glyphosate is currently being used in many situations throughout New Zealand that could easily lead to further resistance developing such as in other perennial fruit crops on roadsides railways amenity areas waste areas fence lines and headlands of crops Following wide consultation as part of a Sustainable Farming Fund project strategies for resistance management in three systems (vineyard and orchards amenity and waste areas and crops and pastures) are suggested Adoption of these strategies will allow glyphosate to continue as a useful herbicide in New Zealand

New and noteworthy Melastomataceae from the Yanachaga-Chemillén National Park and surrounding areas in Oxapampa, Pasco, Peru

Phytotaxa ◽  
2018 ◽  
Vol 374 (3) ◽  
pp. 185 ◽  
Author(s):  
FABIÁN A. MICHELANGELI ◽  
RENATO GOLDENBERG
Keyword(s):  
National Park ◽  
Leaf Surface ◽  
Nodal Line ◽  
Abaxial Surface ◽  
North East ◽  
The North ◽  
The Andes ◽  
Abaxial Leaf Surface ◽  
Surrounding Areas ◽  
Sclerophyllous Forests

We describe six new species of Melastomataceae from the Yanachaga-Chemillén National Park and surrounding areas from the Department of Pasco, Province of Oxapampa in Central Peru. Macrocentrum andinum is the first species of the genus described from the Andes, found along creeks at 400–500 m elev. and characterized by its anysophyllous leaves, pubescent stems and four-merous flowers. Meriania rubriflora is found in forests above 2200 m elev. and it is characterized by stem nodes with stipular flaps, leaves with an acute base and four merous, deep red flowers. Miconia palcazuana is found along rivers and streams at 300–400 m on the eastern flank of the park, and it can be distinguished by its flowers with pink anthers with glands on the connective and narrowly oblanceolate to elliptic-lanceolate leaves. Miconia yanachagaensis grows in the dwarf-sclerophyllous forests at the top of ridges and grasslands over 2800 m elev. and it is characterized by its long dendritic-pedicellate trichomes on the abaxial leaf surface, the stems flattened to terete and the presence of a conspicuous annular nodal line. Triolena rojasae is found growing on rocks along the Palcazú River and its tributaries, and it is characterized by its lanceolate-crenate leaves. Triolena vasquezii grows on the northern end of the Huancabamba canyon and the North East portion of the park and can be distinguished by its pustulate leaves with purple abaxial surface and anthers with two ventral appendages. We also present the first report of the genus Wurdastom for Peru.

scholarly journals Effect of Fungicide Mobility and Application Timing on the Management of Grape Powdery Mildew

Plant Disease ◽  
2020 ◽  
Vol 104 (4) ◽  
pp. 1167-1174 ◽  
Author(s):  
Brent Warneke ◽  
Lindsey D. Thiessen ◽  
Walter F. Mahaffee
Keyword(s):  
Powdery Mildew ◽  
Leaf Surface ◽  
Quality Standards ◽  
Pinot Noir ◽  
Abaxial Surface ◽  
Phenological Stages ◽  
Application Timing ◽  
Abaxial Leaf Surface ◽  
Detached Leaves ◽  
Grape Powdery Mildew

Grape powdery mildew (GPM) fungicide programs consist of 5 to 15 applications, depending on region or market, in an attempt to achieve the high fruit quality standards demanded by the market. Understanding how fungicides redistribute and targeting redistributing fungicide to critical crop phenological stages could improve fungicide protection of grape clusters. This study evaluated fungicide redistribution in grapevines from major fungicide groups labeled for GPM control. Translaminar and xylem redistribution was examined by placing fungicide-impregnated filter disks on the adaxial or abaxial leaf surface of detached leaves for 10 min and then incubating for 48 h before inoculating the abaxial surface with conidia. Vapor redistribution used Teflon disks sprayed with fungicides and placed on the abaxial leaf surface of detached leaves 48 h before inoculation. Disease development was rated 10 days later. Translaminar movement through calyptra was tested using flowering potted vines. All fungicides tested redistributed through at least one mechanism. Fungicide timing at critical phenological stages (early, mid, and late bloom) was assessed in small plots of cultivar Pinot noir vines. The application of trifloxystrobin, quinoxyfen, or fluopyram at different bloom stages showed that applications initiated at end of bloom resulted in the lowest berry infection probabilities of 0.073, 0.097, and 0.020, respectively. The results of this study suggest that integrating two carefully timed applications of redistributing fungicides initiated at end of bloom into a fungicide program may be an effective strategy for wine grape growers in western Oregon to produce fruit with low GPM infection.

scholarly journals Non‐target‐site mechanism of glyphosate resistance in Italian ryegrass ( Lolium multiflorum )

2018 ◽  
Vol 18 (3) ◽  
pp. 127-135 ◽  
Author(s):  
Kohei Kurata ◽  
Yuki Niinomi ◽  
Yoshiko Shimono ◽  
Masahiro Miyashita ◽  
Tohru Tominaga
Keyword(s):  
Lolium Multiflorum ◽  
Glyphosate Resistance ◽  
Target Site ◽  
Italian Ryegrass

scholarly journals Confirmation of glyphosate resistance in two species of ryegrass from New Zealand vineyards

2013 ◽  
Vol 66 ◽  
pp. 89-93 ◽  
Author(s):  
H. Ghanizadeh ◽  
K.C. Harrington ◽  
T.K. James ◽  
D.J. Woolley
Keyword(s):  
New Zealand ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Lolium Multiflorum ◽  
Glyphosate Resistance ◽  
Italian Ryegrass ◽  
Two Populations

Plants were obtained from two populations of Italian ryegrass (Lolium multiflorum) and three populations of perennial ryegrass (Lolium perenne) from different vineyards in Marlborough and Nelson that were suspected of being resistant to glyphosate following many consecutive applications of this herbicide over recent years Each population was multiplied by splitting out tillers and this was also done for plants taken from a population of each species from Manawatu pastures where they had not been exposed to glyphosate application A doseresponse experiment showed that four populations taken from the vineyards were about 10 times as resistant to glyphosate as those plants that had not been previously exposed to the herbicide The experiment was repeated and showed one perennial ryegrass population to have a 30fold level of resistance These are the first confirmed cases of glyphosate resistance within New Zealand

scholarly journals Transcriptome Analysis Identifies Candidate Target Genes Involved in Glyphosate-Resistance Mechanism in Lolium multiflorum

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 685
Author(s):  
Joanei Cechin ◽  
Cristiano Piasecki ◽  
Daiane P. Benemann ◽  
Frederico S. Kremer ◽  
Vanessa Galli ◽  
...  
Keyword(s):  
Target Genes ◽  
De Novo ◽  
Average Length ◽  
Lolium Multiflorum ◽  
Significant Proportion ◽  
Resistance Mechanism ◽  
Glyphosate Resistance ◽  
Italian Ryegrass ◽  
Weed Species ◽  
Candidate Target

Italian ryegrass (Lolium multiflorum; LOLMU) is one of the most troublesome weeds in temperate regions in the world. This weed species interfere with wheat, corn, rye, and oat, causing significant crop yield losses. This species has evolved glyphosate resistance, making it difficult to control. The mechanisms of glyphosate resistance are still unknown, and an understanding thereof will favor the development of new strategies of management. The present study is the first transcriptome study in LOLMU using glyphosate-resistant and -sensitive biotypes, aiming to identify and to provide a list of the candidate target genes related to glyphosate resistance mechanism. The transcriptome was assembled de novo, producing 87,433 contigs with an N50 of 740 bp and an average length of 575 bp. There were 92 and 54 up- and down-regulated genes, respectively, in the resistant biotype, while a total of 1683 were differentially expressed in the sensitive biotype in response to glyphosate treatment. We selected 14 highly induced genes and seven with repressed expression in the resistant biotype in response to glyphosate. Of these genes, a significant proportion were related to the plasma membrane, indicating that there is a barrier making it difficult for glyphosate to enter the cell.

Influence of weed management measures on glyphosate resistance and endophyte infection in naturalized Italian ryegrass (Lolium multiflorum )

2017 ◽  
Vol 17 (2) ◽  
pp. 84-90 ◽  
Author(s):  
Valentina Dwi Suci Handayani ◽  
Yuki Tanno ◽  
Masayuki Yamashita ◽  
Hiroyuki Tobina ◽  
Minoru Ichihara ◽  
...  
Keyword(s):  
Weed Management ◽  
Lolium Multiflorum ◽  
Glyphosate Resistance ◽  
Italian Ryegrass ◽  
Management Measures ◽  
Endophyte Infection

scholarly journals Infection Studies of Mycosphaerella fijiensis on Banana and the Control of Black Sigatoka with Chlorothalonil

Plant Disease ◽  
1998 ◽  
Vol 82 (11) ◽  
pp. 1185-1190 ◽  
Author(s):  
J. R. Washington ◽  
J. Cruz ◽  
F. Lopez ◽  
M. Fajardo
Keyword(s):  
Disease Control ◽  
Leaf Surface ◽  
Infected Leaf ◽  
Mycosphaerella Fijiensis ◽  
Black Sigatoka ◽  
Abaxial Surface ◽  
Disease Symptoms ◽  
Adaxial Surface ◽  
Abaxial Leaf Surface ◽  
Banana Leaves

Infection studies with Mycosphaerella fijiensis, causal agent of black Sigatoka disease of banana (Musa AAA), demonstrated that the abaxial leaf surface is the primary infection site. Inoculation of banana plants with M. fijiensis ascospores on the abaxial surface of young leaves resulted in disease symptoms in 100% of the leaves inoculated within 18 to 30 days; whereas only 5% of the leaves inoculated on the adaxial surface showed black Sigatoka symptoms within 10 weeks. Disease symptoms appeared more rapidly on the new, emerging leaves than on the first and second fully expanded leaves. Application of chlorothalonil (1.08 kg a.i. ha-1) to the abaxial surface of emerging leaves resulted in 99 to 100% disease control in the treated area. When the emerging leaf was not sprayed until fully expanded, disease control was reduced to 76 to 80%. Application of chlorothalonil to the adaxial surface of banana leaves had little or no impact on disease control. Chlorothalonil arrested hyphal growth when applied to banana leaves after ascospores had already germinated and reduced the rate of lesion expansion when applied to the abaxial leaf surface after symptom appearance. Chlorothalonil was less effective than systemic fungicides in reducing production of M. fijiensis pseudothecia in infected tissue. When systemic and protectant fungicides were applied to infected leaf tissue, none of the fungicides affected the viability of ascospores that were discharged from pseudothecia produced in that tissue. For successful control of black Sigatoka with chlorothalonil, deposition of the fungicide on the abaxial leaf surface is essential.

Sign in / Sign up

Export Citation Format

Share Document