Induced novel psbA mutation (Ala251 to Thr) in higher plants confers resistance to PSII inhibitor metribuzin in Lens culinaris

McMurray LS, Preston C, Vandenberg A, Mao D, Bett KE, Paull JG. Induced novel psbA mutation (Ala251 to Thr) in higher plants confers resistance to PSII inhibitor metribuzin in Lens culinaris. Pest Management Science. 2019.
Publication Year
2019
DOI
10.1002/ps.5328
Cross Reference

BACKGROUND

Weed competition is a major limitation to worldwide lentil (Lens culinaris Medik.) production in part due to limited effective safe herbicide options. Metribuzin is a photosystem II inhibiting herbicide that provides broad spectrum weed control, however it causes excessive injury in lentil. Dose response analysis of photosystem II inhibiting herbicides and DNA sequencing of the psbA chloroplast gene occurred to quantify the spectrum and mechanism of herbicide resistance in two ethyl‐methanesulfonate induced mutant lentils.

RESULTS

Compared to susceptible parent PBA Flash, the level of metribuzin resistance was 33‐fold for mutant M043 and 10‐fold for M009. No improvement in resistance occurred in either mutant to bromoxynil, diuron, bromacil and atrazine herbicides. Nucleotide sequencing of the psbA gene of both mutants identified a substitution at position 751 compared to PBA Flash. The resulting deduced amino acid sequence indicated an Ala251Thr substitution as being most likely responsible for the high level of metribuzin resistance.

CONCLUSIONS

The Ala251Thr substitution discovered in this study is unique in mutagenised higher plants and the first report of an induced psbA target site mutation in higher plants. This target site metribuzin resistance is likely to have a significant impact on lentil production in Australia and worldwide