Traits Development Center, Basf, Luis Eduardo Magalhães, Bahia, Brazil.
Department of Plant Breeding, Institute for Sustainable Agriculture (IAS-CSIC), Alameda del Obispo, 14004 Cordoba, Spain.
Pestic Biochem Physiol. 2024 Jan;198:105737. doi: 10.1016/j.pestbp.2023.105737. Epub 2023 Dec 15.
Italian ryegrass (Lolium multiflorum L.) is an invasive species widely spread in croplands worldwide. The intensive use of glyphosate has resulted in the selection of resistance to this herbicide in Italian ryegrass. This work characterized the response to glyphosate of Italian ryegrass populations from the South and Southwest regions of Paraná, Brazil. A total of 44 Italian ryegrass populations were collected in farming areas, and were classified for glyphosate resistance with 75% of populations resistant to gloyphosate. Of these, 3 resistant (VT05AR, MR20AR and RN01AR) and three susceptible (VT07AS, MR05AS and RN01AS) of these populations were selected to determine the resistance level and the involvement of the target site mechanisms for glyphosate resistance. Susceptible populations GR ranged from 165.66 to 218.17 g.e.a. ha and resistant populations from 569.37 to 925.94, providing RI ranging from 2.88 and 4.70. No mutation in EPSPS was observed in the populations, however, in two (MR20AR and RN02AR) of the three resistant populations, an increase in the number of copies of the EPSPs gene (11 to 57×) was detected. The number of copies showed a positive correlation with the gene expression (R = 0.86) and with the GR of the populations (R = 0.81). The increase in EPSPS gene copies contributes to glyphosate resistance in Italian ryegrass populations from Brazil.
多花黑麦草（Lolium multiflorum L.）是一种广泛分布于世界各地农田的入侵物种。草甘膦的大量使用导致了多花黑麦草对这种除草剂的抗性选择。本研究对来自巴西南里奥格兰德州和西南部的多花黑麦草种群对草甘膦的反应进行了特征描述。共采集了 44 个来自农田的多花黑麦草种群，并对其进行了草甘膦抗性分类，其中 75%的种群对草甘膦具有抗性。在这些抗性种群中，选择了 3 个抗性（VT05AR、MR20AR 和 RN01AR）和 3 个敏感（VT07AS、MR05AS 和 RN01AS）种群，以确定抗性水平和靶标位点机制对草甘膦抗性的参与。敏感种群 GR 范围为 165.66 至 218.17 g.e.a. ha，而抗性种群范围为 569.37 至 925.94，提供的 RI 范围为 2.88 至 4.70。未观察到种群中 EPSPS 基因发生突变，但在 3 个抗性种群中的 2 个（MR20AR 和 RN02AR）中，EPSPS 基因的拷贝数增加了 11 至 57 倍。拷贝数与基因表达呈正相关（R = 0.86），与种群的 GR 呈正相关（R = 0.81）。EPSPS 基因拷贝数的增加有助于巴西多花黑麦草种群对草甘膦的抗性。
