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

Abstract

In Shizuoka Prefecture, Japan, glyphosate-resistant Lolium multiflorum is a serious problem on the levees of rice paddies and in wheat fields. The mechanism of resistance of this biotype was analyzed. Based on LD 50 , the resistant population was 2.8-5.0 times more resistant to glyphosate than the susceptible population. The 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) gene sequence of the resistant biotype did not show a non-synonymous substitution at Pro106, and amplification of the gene was not observed in the resistant biotype. The metabolism and translocation of glyphosate were examined 4 days after application through the direct detection of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) using liquid chromatograph-tandem mass spectrometer (LC-MS/MS). AMPA was not detected in either biotype in glyphosate-treated leaves or the other plant parts. The respective absorption rates of the susceptible and resistant biotypes were 37.90 AE 3.63% and 41.09 AE 3.36%, respectively, which were not significantly different. The resistant biotype retained more glyphosate in a glyphosate-treated leaf (91.36 AE 1.56% of absorbed glyphosate) and less in the untreated parts of shoots (5.90 AE 1.17%) and roots (2.76 AE 0.44%) compared with the susceptible biotype, 79.58 AE 3.73%, 15.77 AE 3.06% and 4.65 AE 0.89%, respectively. The results indicate that the resistance mechanism is neither the acquisition of a metabolic system nor limiting the absorption of glyphosate but limited translocation of the herbicide in the resistant biotype of L. multiflorum in Shizuoka Prefecture.

Non-target-Site Resistance in Lolium spp. Globally: A Review

“…Most cases of NTSR to glyphosate in Lolium spp. are due to reduced translocation, with more than 20 reports to date in several countries, including Australia, Brazil, Chile, France, Italy, Japan, New Zealand, Portugal, Spain, and the United States (Mississippi and Oregon) (Ferreira et al, 2006;Michitte et al, 2007;Perez-Jones et al, 2007;Yu et al, 2007;Nandula et al, 2008;Ge et al, 2012;Ghanizadeh et al, 2015b;Fernández-Moreno et al, 2017;Kurata et al, 2018). Some authors also reported lower spray retention and foliar uptake from the abaxial leaf surface, along with reduced translocation (Michitte et al, 2007).…”

“…Reduced glyphosate translocation in resistant plants keeps the herbicide in the source leaves, away from the meristematic tissue, enabling survival after treatment (Kurata et al, 2018). Susceptible biotypes commonly translocate glyphosate out of the treated leaves into non-treated leaves, meristematic tissues, stems and roots (Lorraine-Colwill et al, 2002;Wakelin et al, 2004;Perez-Jones et al, 2007;Yu et al, 2009a).…”

“…Susceptible biotypes commonly translocate glyphosate out of the treated leaves into non-treated leaves, meristematic tissues, stems and roots (Lorraine-Colwill et al, 2002;Wakelin et al, 2004;Perez-Jones et al, 2007;Yu et al, 2009a). Different populations exhibit a wide range of resistance levels, ranging from three-to 25-fold compared to susceptible populations (Ghanizadeh et al, 2015b;Kurata et al, 2018).…”

Emergence of Glyphosate- and Glufosinate-resistant Italian Ryegrass (<i>Lolium multiflorum</i>) Populations in Japanese Pear Orchards in Japan and their Responses to Several Foliar-applied Herbicides

“…It is necessary to monitor the levels of resistance of this weed to glyphosate and glufosinate in the Japanese pear orchards. Although the mechanism underlying glyphosate resistance is limited translocation of the herbicide in the resistant biotype of L. multiflorum in rice paddy levees in Shizuoka Prefecture (Kurata et al 2018), the mechanism underlying glyphosate resistance in L. multiflorum in Japanese pear orchards is unclear. In the future, it is necessary to investigate the mechanism underlying the multiple resistance to glyphosate and glufosinate.…”

Dynamics of Glyphosate Resistance in Lolium perenne: Pollen-Mediated Gene Flow under Field Conditions in Argentina

“…Until now, around 500 cases of herbicide-resistant weed populations have been reported [2]. Among these, the genus Lolium has shown high tendency to evolve herbicide resistance, and it includes species of the more troublesome cases of resistance in the world [2][3][4][5][6][7].…”