Radish (Raphanus sativus L.) and wild radish (R. raphanistrum L.) are troublesome agricultural weeds in several areas worldwide, with populations resistant to acetolactate synthase (ALS) inhibitor herbicide. Information on the mechanisms of resistance is important for management and developing novel solutions to control resistant populations. The objective of this work was to determine the ALS‐resistance mechanisms in radish and wild radish biotypes resistant to ALS‐inhibiting herbicides. Resistance levels were determined by dose‐response curve using several rates of metsulfuron‐methyl herbicide in susceptible (JUC1) and resistant (JUC2, CRA3) radish, and susceptible (CAF1) and resistant (CAF2, CAF3) wild radish biotypes. The mechanism was evaluated by the in vitro activity of the ALS enzyme with imazapic herbicide and ALS gene sequencing. All resistant biotypes were insensitive to metsulfuron‐methyl and imazapic herbicides. The rate of metsulfuron‐methyl to reduce 50% growth of the plants (GR₅₀) were 17‐ to 60‐fold (JUC2, CRA3) and 9‐ to 21‐fold (CAF2 and CAF3) higher than the susceptible biotypes of radish and wild radish, respectively. One‐point mutation in the ALS gene, Trp‐574‐Leu, was found in all resistant radish biotypes, whereas a second point mutation, Ala‐360‐Ser, was found in CAF2, CAF3, and JUC2 resistant biotypes. Changes in kinetic parameters of the ALS enzyme were found in all resistant biotypes evaluated, causing reduction of the herbicide affinity in the target‐site of action. Trp‐574‐Leu amino acid substitution resulted in resistance to sulfonylurea, imidazolinone, and triazolopyrimidine groups, with the survival greater than 75% of the plants, depending on the herbicide applied at labeled rate.

中文翻译：

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来自巴西的萝卜和野生萝卜生物型对ALS抑制除草剂的目标位抗性和交叉抗性

萝卜（Raphanus sativus L.）和野生萝卜（R. raphanistrumL.）是世界各地几个地区的麻烦性农业杂草，其种群对乙酰乳酸合酶（ALS）抑制剂除草剂具有抗性。有关抗性机制的信息对于管理和开发新的解决方案以控制抗性种群很重要。这项工作的目的是确定对ALS抑制除草剂有抗性的萝卜和野萝卜生物型中的ALS抗性机制。耐药水平由剂量响应曲线确定，使用易感性（JUC1）和耐药性（JUC2，CRA3）萝卜和易感性（CAF1）和耐药性（CAF2，CAF3）野生萝卜生物型的几种甲磺隆除草剂比率。通过具有伊马替比除草剂的ALS酶的体外活性和ALS基因测序来评估该机制。所有抗性生物型均对甲磺隆甲基和吡虫啉除草剂不敏感。甲磺隆减少植物50％生长的速率（GR₅₀）分别比萝卜和野生萝卜的易感生物型高17至60倍（JUC2，CRA3）和9至21倍（CAF2和CAF3）。在所有抗性萝卜生物型中均发现了ALS基因Trp-574-Leu的单点突变，而在CAF2，CAF3和JUC2抗性生物型中发现了第二个点突变Ala-360-Ser。在评估的所有抗性生物类型中均发现了ALS酶动力学参数的变化，从而导致除草剂亲和力在目标作用位点降低。Trp-574-Leu氨基酸取代导致对磺酰脲，咪唑啉酮和三唑并嘧啶基团的抗性，其存活率大于植物的75％，具体取决于以标记比例施用的除草剂。