Herbicide resistant weeds are becoming increasingly common, threatening global food security. Here, we present BrIFAR: a new model system for the functional study of mechanisms of herbicide resistance in grass weeds. We have developed a large collection of Brachypodium accessions, the BrI collection, representing a wide range of habitats. Wide screening of the responses of the accessions to four major herbicide groups (PSII, ACCase, ALS/AHAS and EPSPS inhibitors) identified 28 herbicide-resistance candidate accessions. Target-site resistance to PSII inhibitors was found in accessions collected from habitats with a known history of herbicide applications. An amino acid substitution in the psbA gene (serine264 to glycine) conferred resistance and also significantly affected the flowering and shoot dry weight of the resistant accession, as compared to the sensitive accession. Non-target site resistance to ACCase inhibitors was found in accessions collected from habitats with a history of herbicide application and from a nature reserve. In-vitro enzyme activity tests and responses following pre-treatment with malathion (a cytochrome-P450 inhibitor) indicated sensitivity at the enzyme level, and give strong support to diclofop-methyl and pinoxaden enhanced detoxification as NTS resistance mechanism. BrIFAR can promote better understanding of the evolution of mechanisms of herbicide resistance and aid the implementation of integrative management approaches for sustainable agriculture.
Bibliographical noteFunding Information:
This study was supported by the Chief Scientist of the Israel Ministry of Agriculture and Rural Development , Hebrew University of Jerusalem Intramural Research Fund Career Development and ADAMA Agricultural Solutions . We thank Dr. R. Ben-David (ARO-Volcani Center, Israel) for providing some of the Brachypodium seeds. We would like to acknowledge Dr. M. Sibony, L. Shaar, T. Kliper and Y. Zait for their excellent assistance with the experiments. M. Matzrafi is indebted to Natan Yafe and Teomim doctoral fellowships awards.
© 2014 Elsevier Ireland Ltd.
- ACCase inhibitors
- ALS/AHAS inhibitors
- EPSPS inhibitor
- Herbicide detoxification
- PSII inhibitors