Department of Applied Biology to Agropecuary, São Paulo State University, Jaboticabal, Brazil.
J Agric Food Chem. 2012 Jan 18;60(2):615-22. doi: 10.1021/jf204089d. Epub 2012 Jan 5.
Digitaria insularis biotypes resistant to glyphosate have been detected in Brazil. Studies were carried out in controlled conditions to determine the role of absorption, translocation, metabolism, and gene mutation as mechanisms of glyphosate resistance in D. insularis. The susceptible biotype absorbed at least 12% more (14)C-glyphosate up to 48 h after treatment (HAT) than resistant biotypes. High differential (14)C-glyphosate translocation was observed at 12 HAT, so that >70% of the absorbed herbicide remained in the treated leaf in resistant biotypes, whereas 42% remained in the susceptible biotype at 96 HAT. Glyphosate was degraded to aminomethylphosphonic acid (AMPA), glyoxylate, and sarcosine by >90% in resistant biotypes, whereas a small amount of herbicide (up to 11%) was degraded by the susceptible biotype up to 168 HAT. Two amino acid changes were found at positions 182 and 310 in EPSPS, consisting of a proline to threonine and a tyrosine to cysteine substitution, respectively, in resistant biotypes. Therefore, absorption, translocation, metabolism, and gene mutation play an important role in the D. insularis glyphosate resistance.
巴西已检测到抗草甘膦的海岛多花木兰生物型。在控制条件下进行了研究，以确定吸收、转运、代谢和基因突变作为海岛多花木兰草甘膦抗性的机制。敏感生物型在处理后 48 小时内吸收至少 12%的 14C-草甘膦（14C-glyphosate），而抗性生物型则吸收较少。在 12 小时时观察到高差异的 14C-草甘膦转运，因此，在抗性生物型中，超过 70%的吸收的除草剂仍留在处理叶中，而在敏感生物型中，96 小时时仍有 42%的除草剂留在处理叶中。草甘膦在抗性生物型中被降解为氨甲基膦酸（AMPA）、乙醛酸和肌氨酸，而在敏感生物型中，直到 168 小时，仍有少量除草剂（高达 11%）被降解。在 EPSPS 中的位置 182 和 310 发现了两个氨基酸变化，分别为脯氨酸到苏氨酸和酪氨酸到半胱氨酸取代，在抗性生物型中。因此，吸收、转运、代谢和基因突变在海岛多花木兰草甘膦抗性中起着重要作用。
