Glyphosate Resistance in Tridax procumbens via a Novel EPSPS Thr-102-Ser Substitution

Jingbo Li, Qiong Peng, Heping Han, Alex Nyporko, Tymofii Kulynych, Qin Yu, Stephen Powles

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


This study confirmed the first case of glyphosate resistance in Tridax procumbens and investigated the glyphosate-resistance mechanisms. Sequencing and cloning of the full 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) coding sequences revealed a point mutation (ACC to TCC) at amino acid position 102, resulting in a novel Thr-102-Ser substitution. Other possible resistance mechanisms (i.e., target-site EPSPS-gene overexpression, nontarget-site differential glyphosate uptake and translocation) were also examined and were unlikely to be involved in resistance in this population. Structural modeling of the wild-type and mutant EPSPS in complex with glyphosate and phosphoenolpyruvate (PEP) revealed that the Thr-102-Ser substitution weakly decreased EPSPS affinity to glyphosate, but sharply increased EPSPS affinity to the natural substrate, PEP. Therefore, this novel mutation is very likely responsible for the observed glyphosate resistance in this tetraploid weed species via dual mechanisms of reducing glyphosate binding and favoring PEP binding to EPSPS.

Original languageEnglish
Pages (from-to)7880-7888
Number of pages9
JournalJournal of Agricultural and Food Chemistry
Issue number30
Publication statusPublished - 1 Aug 2018


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