Expression of genes related to the mechanism of resistance of Conyza sumatrensis to glyphosate

Abstract

The elucidation of the resistance mechanism of weeds to herbicides is important for management practices. The objective of this work was to investigate the resistance mechanism of glyphosate-resistant C. sumatrensis biotypes by determining the expression levels of the constitutive gene epsps and two ABC transport protein-coding genes designated m7 and m11 with RT-qPCR. Two biotypes of C. sumatrensis were evaluated: one resistant and one susceptible to glyphosate. The treatments consisted of the absence or application of two doses of glyphosate (1,080 and 8,640 g a.e. ha-1). Plant leaves were collected at 1 and 4 days after herbicide application. No difference was observed in epsps gene expression between the studied biotypes. The expression of the m7 and m11 genes revealed that both genes had higher relative expression in the resistant biotype with the application of glyphosate at both doses. The overexpression of the m7 and m11 genes in the resistant biotype treated with glyphosate reveals that these genes play a role in herbicide resistance. These genes may be involved in the sequestration of glyphosate into the vacuole lumen in the resistant C. sumatrensis biotype studied.

Validation of Reference Genes for Quantitative PCR in Johnsongrass (Sorghum halepense L.) under Glyphosate Stress

“…Some glyphosate-resistant weeds, such as Lolium perenne [ 41 ], Eleusine indica [ 21 ] and Conyza canadensis [ 20 ], overexpress EPSPS. In our study, the expression of EPSPS showed no increase after treatment with glyphosate, according to analysis of the best reference genes (ARI8 and PP2A); likewise, in Coniza sumatrensis [ 42 ] and Amaranthus tuberculatus [ 43 ], other glyphosate-resistant weeds, EPSPS expression shows no variation. The use of ACT or ALS1 as reference genes revealed an under-expression of our gene of interest.…”