Pollen-mediated gene flow from glyphosate-resistant common waterhemp (Amaranthus rudis Sauer): consequences for the dispersal of resistance genes

Authors

Debalin Sarangi, University of Nebraska-LincolnFollow
Andrew J. Tyre, University of Nebraska-LincolnFollow
Eric L. Patterson, Colorado State UniversityFollow
Todd A. Gaines, Colorado State UniversityFollow
Suat Irmak, University of Nebraska-LincolnFollow
Stevan Z. Knezevic, University of Nebraska - LincolnFollow
John L. Lindquist, University of Nebraska-LincolnFollow
Amit J. Jhala, University of Nebraska-LincolnFollow

ORCID IDs

Amit J. Jhala

Document Type

Article

Date of this Version

2017

Citation

Scientific Reports, 7:44913, DOI: 10.1038/srep44913

Comments

This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

Gene flow is an important component in evolutionary biology; however, the role of gene flow in dispersal of herbicide-resistant alleles among weed populations is poorly understood. Field experiments were conducted at the University of Nebraska-Lincoln to quantify pollen-mediated gene flow (PMGF) from glyphosate-resistant (GR) to -susceptible (GS) common waterhemp using a concentric donorreceptor design. More than 130,000 common waterhemp plants were screened and 26,199 plants were confirmed resistant to glyphosate. Frequency of gene flow from all distances, directions, and years was estimated with a double exponential decay model using Generalized Nonlinear Model (package gnm) in R. PMGF declined by 50% at source, whereas 90% reduction was found at 88 m (maximum) depending on the direction of the pollen-receptor blocks. Amplification of the target site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), was identified as the mechanism of glyphosate resistance in parent biotype. The EPSPS gene amplification was heritable in common waterhemp and can be transferred via PMGF, and also correlated with glyphosate resistance in pseudo-F₂ progeny. This is the first report of PMGF in GR common waterhemp and the results are critical in explaining the rapid dispersal of GR common waterhemp in Midwestern United States.