1 October 2013 Mechanism of Resistance and Inheritance in Glyphosate Resistant Palmer amaranth (Amaranthus palmeri) Populations from New Mexico, USA
Mohsen Mohseni-Moghadam, Jill Schroeder, Jamshid Ashigh
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Abstract

Two populations of Palmer amaranth from New Mexico have been confirmed to be resistant to glyphosate. In the present study, the molecular basis of resistance and the mode of inheritance of resistance in those populations were investigated. Quantitative real-time polymerase chain reaction analysis indicated up to an eightfold increase in genomic EPSPS copy number in glyphosate resistant plants compared with susceptible plants. The relative genomic EPSPS copy number of resistant plants was positively correlated with the relative EPSPS cDNA expression levels. Eight hours after treatment with glyphosate, the shikimate accumulation levels in resistant plants were negatively correlated with the genomic EPSPS copy numbers. Multiple sequencing of the EPSPS cDNA of resistant plants did not reveal any glyphosate resistance-conferring mutations. The evaluation of F1, reciprocal F1, and F2 Palmer amaranth families indicated that resistance to glyphosate does not follow a single-gene segregation pattern. Results suggest that the EPSPS amplification is the primary molecular basis of resistance in glyphosate resistant populations of Palmer amaranth from New Mexico.

Nomenclature: Glyphosate, Palmer amaranth, Amaranthus palmeri S. Watts.

Weed Science Society of America
Mohsen Mohseni-Moghadam, Jill Schroeder, and Jamshid Ashigh "Mechanism of Resistance and Inheritance in Glyphosate Resistant Palmer amaranth (Amaranthus palmeri) Populations from New Mexico, USA," Weed Science 61(4), 517-525, (1 October 2013). https://doi.org/10.1614/WS-D-13-00028.1
Received: 20 February 2013; Accepted: 1 April 2013; Published: 1 October 2013
KEYWORDS
Bases of resistance
Carya illinoinensis (Wangenh.) K. Koch
EPSPS cDNA expression
genomic EPSPS copy numbers
inheritance of resistance
Pecan orchards
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