Multiple mechanism confers natural tolerance of three lilyturf species to glyphosate

Abstract

A combination of unique EPSPS structure and increased gene copy number and expression contribute to natural glyphosate tolerance in three lilyturf species. A few plants are naturally tolerant to glyphosate, the most widely used non-selective herbicide worldwide. Here, the basis for natural tolerance to glyphosate in three lilyturf species, Ophiopogon japonicus (OJ), Liriope spicata (LS), and Liriope platyphylla (LP), is characterized. These species tolerate glyphosate at about five times the commercially recommended field dose. They share three unique amino acids in their 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) that affect glyphosate binding. These correspond to Asp71Met, Ala112Ile, and Val201Met amino acid variations compared to 231 other published plant EPSPS amino acid sequences. There was also a common deletion at 91 of a highly conserved glutamic acid. Glyphosate-treated lilyturf plants accumulated little shikimic acid but had significantly higher levels of EPSPS mRNA than initially expressed in the control. The IC50 of LsEPSPS was 14.0 µM compared to the 5.1 µM of Arabidopsis thaliana. The higher K m and K i values of LsEPSPS kinetics showed that LsEPSPS had lower substrate binding affinity to glyphosate. Overexpression of LsEPSPS in the recombinant E. coli BL21 (DE3) strain enhanced its tolerance to glyphosate. Both OJ and LS had two copies of the EPSPS gene, while LP had three copies. Therefore, a combination of unique EPSPS structure and increased gene copy number and expression contribute to natural glyphosate tolerance in the three lilyturf species.

From tolerance to resistance: mechanisms governing the differential response to glyphosate in Chloris barbata

“…Several mutations in the EPSPS gene have been suggested as contributing to glyphosate resistance such as: Val133‐Ile and Pro382‐Leu in E. indica , Asp71‐Met, Ala112‐Ile and Val201‐Met in Ophiopogon japonicus , Liriope platyphylla and L. spicata , and Glu91‐Ala in C. truncata , among others. However, the mutations responsible for conferring resistance to glyphosate must occur in the conserved region of the EPSPS gene, which includes amino acid positions 95 to 107, as demonstrated in E. coli . To date, only two mutations (Thr102 and Pro106) occurring in this region have been found .…”

“…However, the mutations responsible for conferring resistance to glyphosate must occur in the conserved region of the EPSPS gene, which includes amino acid positions 95 to 107, 4 as demonstrated in E. coli. 45,46 To date, only two mutations (Thr102 and Pro106) occurring in this region have been found. 3,21 Our results clearly demonstrate that the mutation Pro106-Ser was involved in the evolution of resistance to glyphosate in C. barbata R plants.…”

First Resistance Mechanisms Characterization in Glyphosate-Resistant Leptochloa virgata

“…In addition, L. virgata was effectively controlled previously with glyphosate (Pérez-López et al, 2014; Alcántara-de la Cruz et al, 2016c). According to bibliography, innate tolerance to glyphosate not involve target site tolerance mechanisms within the same species, and the tolerant populations generally are compared with sensitive populations of other species (Yuan et al, 2002; Alcántara-de la Cruz et al, 2016a; Fernández-Moreno et al, 2016; Mao et al, 2016). To demonstrate the innate glyphosate tolerance in species such as: Avena sterilis, Cologania broussonetii, Dicliptera chinensis, Liriope platyphylla, Liriope spicata, Ophiopogon japonicas , among others, it has been necessary compare them with glyphosate sensitive species.…”

In vivo and in vitro evidence for the inhibition of homogentisate solanesyltransferase by cyclopyrimorate

“…the K i value for glyphosate is approximately 2.4-fold higher than the K m value. 31 DMC exhibited mixed non-competitive A. thaliana HST inhibition with respect to FPP (Fig. 6), whereas haloxydine inhibited C. reinhardtii HST uncompetitively with respect to FPP, thus their results were inconsistent.…”