Krishnan Mahima, Petrovic Tijana, Schwerdt Julian G, Merriam Alicia B, Hereward James P, Preston Christopher
School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, Australia.
School of Biological Sciences, University of Queensland, Brisbane, Australia.
Pest Manag Sci. 2025 Jan;81(1):141-148. doi: 10.1002/ps.8413. Epub 2024 Sep 13.
2,4-Dichlorophenoxyacetic acid (2,4-D) and other auxinic herbicides are important for weed control in cropping systems globally. Weeds with resistance to 2,4-D and other auxinic herbicides have evolved, including several populations of Sonchus oleraceus from multiple sites in Australia. We report the underlying mechanism in these populations that gives rise to auxinic herbicide resistance.
We studied a total of three susceptible and eight resistant Sonchus oleraceus populations. All resistant populations had a deletion of three amino acids flanking the degron sequence of an Aux/IAA gene, SoIAA20, which was not found in the three susceptible populations. The eight populations with the resistant allele were also resistant to dicamba, fluroxypyr and clopyralid. The resistant plants also had reduced movement of 2,4-D out of the treated tissues compared to susceptible plants.
The paired deletion flanking the degron region of SoIAA20 likely provides resistance to 2,4-D by restricting the movement of 2,4-D from the treated tissue to the rest of the plant. We hypothesise that this deletion keeps the 2,4-D bound to the target site. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
2,4-二氯苯氧乙酸（2,4-D）和其他生长素类除草剂对于全球种植系统中的杂草控制至关重要。对2,4-D和其他生长素类除草剂具有抗性的杂草已经进化出来，包括来自澳大利亚多个地点的几个苣荬菜种群。我们报告了这些种群中产生生长素类除草剂抗性的潜在机制。
我们总共研究了3个敏感苣荬菜种群和8个抗性苣荬菜种群。所有抗性种群在一个Aux/IAA基因SoIAA20的降解序列侧翼缺失了三个氨基酸，而在3个敏感种群中未发现这种缺失。具有抗性等位基因的8个种群对麦草畏、氟草烟和氯吡嘧磺隆也具有抗性。与敏感植物相比，抗性植物中2,4-D从处理组织中向外运输的量也减少。
SoIAA20降解区域侧翼的成对缺失可能通过限制2,4-D从处理组织向植物其他部位的运输而赋予对2,4-D的抗性。我们推测这种缺失使2,4-D与靶位点结合。© 2024作者。《害虫管理科学》由约翰·威利父子有限公司代表化学工业协会出版。
