Send to

Choose Destination
See comment in PubMed Commons below
Pest Manag Sci. 2014 Dec;70(12):1902-9. doi: 10.1002/ps.3754. Epub 2014 Mar 20.

EPSPS amplification in glyphosate-resistant spiny amaranth (Amaranthus spinosus): a case of gene transfer via interspecific hybridization from glyphosate-resistant Palmer amaranth (Amaranthus palmeri).

Author information

Crop Production Systems Research Unit, USDA-ARS, Stoneville, MS, USA.



Amaranthus spinosus, a common weed of pastures, is a close relative of Amaranthus palmeri, a problematic agricultural weed with widespread glyphosate resistance. These two species have been known to hybridize, allowing for transfer of glyphosate resistance. Glyphosate-resistant A. spinosus was recently suspected in a cotton field in Mississippi.


Glyphosate-resistant A. spinosus biotypes exhibited a fivefold increase in resistance compared with a glyphosate-susceptible biotype. EPSPS was amplified 33-37 times and expressed 37 times more in glyphosate-resistant A. spinosus biotypes than in a susceptible biotype. The EPSPS sequence in resistant A. spinosus plants was identical to the EPSPS in glyphosate-resistant A. palmeri, but differed at 29 nucleotides from the EPSPS in susceptible A. spinosus plants. PCR analysis revealed similarities between the glyphosate-resistant A. palmeri amplicon and glyphosate-resistant A. spinosus.


Glyphosate resistance in A. spinosus is caused by amplification of the EPSPS gene. Evidence suggests that part of the EPSPS amplicon from resistant A. palmeri is present in glyphosate-resistant A. spinosus. This is likely due to a hybridization event between A. spinosus and glyphosate-resistant A. palmeri somewhere in the lineage of the glyphosate-resistant A. spinosus plants. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.


Amaranthus spinosus; EPSPS; gene amplification; gene transfer; glyphosate; herbicide resistance; interspecific hybridization; introgression

[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley
    Loading ...
    Support Center