Metabolism-based resistance to herbicides in black-grass

Resistance to herbicides in weeds can be due to alteration(s) in the gene encoding the herbicide target site, or to herbicide degradation via a deviation in plant general metabolism. If target-site-based resistance is easy to study, the multigenic control of metabolism-based resistance renders it much more complex to study. Metabolism-based resistance to herbicides represents the major part of herbicide resistance in black-grass. Its most likely basis is an overexpression of genes encoding enzymes degrading herbicides. We thus seek to identify such overexpressed genes by comparing the transcriptomes of resistant and sensitive black-grass individuals belonging to an F2 line segregating for two resistance genes. Given there are no genomic tools developed for black-grass, this approach will use heterologous hybridisation onto a wheat Affymetrix microarray. Comparison using heterologous hybridisation onto a wheat whole-genome microarray of transcriptome of three pools of black-grass plants obtained 2h30 after herbicide spraying at field rate. The three pools correspond to: · Sensitive plants (killed by herbicide). · Moderately resistant plants (growth impaired by herbicide but plants still alive) · Resistant plants (growth unimpaired by herbicide) 6 arrays - wheat