A novel TIPT double mutation in EPSPS conferring glyphosate resistance in tetraploid Bidens subalternans

Hudson K. Takano, Vanessa N. A. Fernandes, Fernando S. Adegas, Rubem S. Oliveira Jr, Philip Westra, Todd A. Gaines, Franck E. Dayana

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


BACKGROUND Bidens subalternans (greater beggarticks) is a tetraploid and troublesome weed infesting annual crops in most tropical regions of the world. A glyphosate-resistant (GR) B. subalternans biotype was detected in a soybean field from Paraguay. A series of physiological and molecular analyses were conducted to elucidate its resistance mechanisms. RESULTS The GR biotype had a high level of resistance (> 15-fold LD50), relative to a glyphosate-susceptible (GS) biotype. Shikimate accumulation was up to ten-fold greater for GS compared with GR. We found no differences in sensitivity when plants were treated and kept under lower (10/4 degrees C) or higher temperatures (25/20 degrees C). GS and GR had the same relative EPSPS gene copy number, and similar glyphosate absorption and translocation rates. Neither biotype metabolized glyphosate. A double amino acid substitution (TIPT - Thr102Ile and Pro106Thr) was found in only one EPSPS allele from one of the two EPSPS homoeologs present in tetraploid GR B. subalternans. CONCLUSION This is the first report of a TIPT double mutation conferring high levels of glyphosate resistance in a weed species. The presence of both wild-type and TIPT mutant EPSPS on the polyploid genome of GR B. subalternans may offset a potential fitness cost, requiring additional research to confirm the absence of deleterious effects. (c) 2019 Society of Chemical Industry
Original languageEnglish
Pages (from-to)95-102
Number of pages8
JournalPest Management Science
Issue number1
Early online dateAug 2019
Publication statusPublished - 1 Jan 2020
Externally publishedYes


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