Characterizing candidate genes for glyphosate resistance in Erigeron bonariensis

Title: Characterizing the expression of candidate genes for herbicide resistance in the
agricultural weed hairy fleabane (Erigeron bonariensis)
Authors: Priyanka Chaudhari, Diana Camarena, and Katherine Waselkov
ABSTRACT
Herbicide resistance is the heritable ability of weeds to survive and reproduce in the presence of
herbicide doses that are lethal to the wild type of the species. Erigeron bonariensis (hairy
fleabane) is an agricultural weed that infests orchards and crop fields in California’s Central
Valley, and has become resistant to the herbicide chemical glyphosate (RoundUp®), through an
unknown genetic mechanism. One mechanism of glyphosate resistance demonstrated in E.
canadensis, a close relative of E. bonariensis, is non-target site reduced translocation of the
herbicide, in which vacuolar sequestration prevents the chemical from spreading around the
plant. Resistance of Erigeron canadensis to glyphosate is believed to involve upregulation of the
target gene EPSPS in combination with the ABC transporter genes M10 and M11. This study
aims to determining through quantitative PCR (qPCR) and RNA-Seq if these candidate genes
provide the mechanism forare involved glyphosate resistance in wild populations of Erigeron
bonariensis. , and/or if there are other genes responsible for the observed glyphosate resistance.
Sample leaves of the weed were collected before and after glyphosate spraying in plants from 10
different populations wild-collected from the Central Valley and two control populations of
Erigeron bonariensis. Response to glyphosate was used to characterize percent resistance for
each wild-collected population. RNA was extracted from the leaves of glyphosate-treated and