Physical Mapping of Amplified Copies of the 5-Enolpyruvylshikimate-3-Phosphate Synthase Gene in Glyphosate-Resistant Amaranthus tuberculatus1[OPEN]
Fluorescence in situ hybridization maps a cluster of EPSPS genes to the pericentromeric region on one pair of homologous chromosomes of glyphosate-resistant Amaranthus tuberculatus. Recent and rapid evolution of resistance to glyphosate, the most widely used herbicides, in several weed species, incl...
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Veröffentlicht in: | Plant physiology (Bethesda) 2016-12, Vol.173 (2), p.1226-1234 |
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Sprache: | eng |
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Zusammenfassung: | Fluorescence in situ hybridization maps a cluster of EPSPS genes to the pericentromeric region on one pair of homologous chromosomes of glyphosate-resistant Amaranthus tuberculatus.
Recent and rapid evolution of resistance to glyphosate, the most widely used herbicides, in several weed species, including common waterhemp (
Amaranthus tuberculatus
), poses a serious threat to sustained crop production. We report that glyphosate resistance in
A
.
tuberculatus
was due to amplification of the 5-enolpyruvylshikimate-3-P synthase (
EPSPS
) gene, which encodes the molecular target of glyphosate. There was a positive correlation between
EPSPS
gene copies and its transcript expression. We analyzed the distribution of
EPSPS
copies in the genome of
A
.
tuberculatus
using fluorescence in situ hybridization on mitotic metaphase chromosomes and interphase nuclei. Fluorescence in situ hybridization analysis mapped the
EPSPS
gene to pericentromeric regions of two homologous chromosomes in glyphosate sensitive
A
.
tuberculatus
. In glyphosate-resistant plants, a cluster of
EPSPS
genes on the pericentromeric region on one pair of homologous chromosomes was detected. Intriguingly, two highly glyphosate-resistant plants harbored an additional chromosome with several
EPSPS
copies besides the native chromosome pair with
EPSPS
copies. These results suggest that the initial event of
EPSPS
gene duplication may have occurred because of unequal recombination mediated by repetitive DNA. Subsequently, gene amplification may have resulted via several other mechanisms, such as chromosomal rearrangements, deletion/insertion, transposon-mediated dispersion, or possibly by interspecific hybridization. This report illustrates the physical mapping of amplified
EPSPS
copies in
A
.
tuberculatus
. |
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ISSN: | 0032-0889 1532-2548 |
DOI: | 10.1104/pp.16.01427 |