Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Jun 4:15:1420009.
doi: 10.3389/fpls.2024.1420009. eCollection 2024.

First case of evolved herbicide resistance in the holoparasite sunflower broomrape, Orobanche cumana Wallr

Affiliations

First case of evolved herbicide resistance in the holoparasite sunflower broomrape, Orobanche cumana Wallr

Shiv Shankhar Kaundun et al. Front Plant Sci. .

Abstract

The development and commercialisation of sunflower varieties tolerant to acetolactate synthase (ALS)-inhibiting herbicides some 20 years ago provided farmers with an alternative method for the cost-effective control of Orobanche cumana. In 2020, however, two independent sunflower broomrape populations from Drama (GR-DRA) and Orestiada (GR-ORE), Greece, were reported to be heavily infested with O. cumana after application of the ALS-inhibiting herbicide imazamox. Here we have investigated the race of GR-DRA and GR-ORE and determined the basis of resistance to imazamox in the two Greek O. cumana samples. Using a set of five diagnostic sunflower varieties characterised by different resistant genes with respect to O. cumana infestation, we have clearly established that the GR-ORE and GR-DRA populations belong to the invasive broomrape races G and G+, respectively. Live underground tubercles and emerged shoots were identified at the recommended field rate of imazamox for GR-DRA and GR-ORE but not for two other standard sensitive populations in a whole plant dose response test using two different herbicide-tolerant sunflower hybrids as hosts. Sequencing of the ALS gene identified an alanine 205 to aspartate mutation in all GR-ORE samples. Most GR-DRA tubercles were characterised by a second serine 653 to asparagine ALS mutation whilst a few GR-DRA individuals contained the A205D mutation. Mutations at ALS codons 205 and 653 are known to impact on the binding and efficacy of imazamox and other imidazolinone herbicides. The knowledge generated here will be important for tracking and managing broomrape resistance to ALS-inhibiting herbicides in sunflower growing regions.

Keywords: Orobanche cumana; herbicide resistance; imazamox; sunflower broomrape; virulence.

PubMed Disclaimer

Conflict of interest statement

All authors are employed by companies of Syngenta Group.

Figures

Figure 1
Figure 1
Responses of four broomrape populations to imazamox in sunflower Hybrid B.
Figure 2
Figure 2
Responses of four broomrape populations to imazamox in sunflower Hybrid A.

Similar articles

Cited by

References

    1. Al-Khatib K., Baumgartner J. R., Peterson D. E., Currie R. S. (1998). Imazethapyr resistance in common sunflower (Helianthus annuus). Weed Sci. 46, 403–407. doi: 10.1017/S0043174500090809 - DOI
    1. Barco-Antoñanzas M., Gil-Monreal M., Eceiza M. V., Royuela M., Zabalza A. (2022). Primary metabolism in an Amaranthus palmeri population with multiple resistance to glyphosate and pyrithiobac herbicides. Plant Sci. 318, 111212. doi: 10.1016/j.plantsci.2022.111212 - DOI - PubMed
    1. Breccia G., Gil M., Vega T., Altieri E., Bulos M., Picardi L., et al. . (2017). Contribution of non-target-site resistance in imidazolinone-resistant Imisun sunflower. Bragantia 76, 536–542. doi: 10.1590/1678-4499.2016.336 - DOI
    1. Brosnan J. T., Vargas J. J., Breeden G. K., Grier L., Aponte R. A., Tresch S., et al. . (2016). A new amino acid substitution (Ala-205-Phe) in acetolactate synthase (ALS) confers broad spectrum resistance to ALS-inhibiting herbicides. Planta 243, 149–159. doi: 10.1007/s00425-015-2399-9 - DOI - PMC - PubMed
    1. Burgos N. R., Tranel P. J., Streibig J. C., Davis V. M., Shaner D., Norsworthy J. K., et al. . (2013). Review: confirmation of resistance to herbicides and evaluation of resistance levels. Weed Sci. 61, 4–20. doi: 10.1614/WS-D-12-00032.1 - DOI