Salgotra Romesh, Chauhan Bhagirath Singh
Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Gatton, QLD 4343, Australia.
School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences & Technology of Jammu, Chatha 180009, India.
Plants (Basel). 2021 Sep 11;10(9):1885. doi: 10.3390/plants10091885.
Sweet summer grass is a problematic weed in the central Queensland region of Australia. This study found glyphosate resistance in two biotypes (R1 and R2) of sweet summer grass. The level of resistance in these biotypes was greater than 8-fold. The glyphosate dose required to reduce dry matter by 50% (GR50) for the resistant populations varied from 1993 to 2100 g ha. A novel glyphosate resistance double point mutation in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene was identified for the first time in sweet summer grass. Multiple mutations, including multiple amino acid changes at the glyphosate target site, as well as mutations involving two nucleotide changes at a single amino acid codon, were observed. Both resistant biotypes exhibited a nucleotide change of CAA to ACA in codon 106, which predicts an amino acid change of proline to a threonine (Pro-106-Thr). In addition, the R1 biotype also possessed a mutation at codon 100, where a nucleotide substitution of T for G occurred (GCT to TCT), resulting in a substitution of serine for alanine (Ala-100-Ser). Understanding the molecular mechanism of glyphosate resistance will help to design effective management strategies to control invasive weeds.
甜夏草是澳大利亚昆士兰州中部地区一种有问题的杂草。本研究在甜夏草的两种生物型（R1和R2）中发现了草甘膦抗性。这些生物型的抗性水平大于8倍。抗性种群将干物质减少50%（GR50）所需的草甘膦剂量在1993至2100克/公顷之间。首次在甜夏草中鉴定出5-烯醇丙酮酸莽草酸-3-磷酸合酶（EPSPS）基因中的一种新型草甘膦抗性双点突变。观察到多个突变，包括草甘膦靶位点的多个氨基酸变化，以及单个氨基酸密码子处涉及两个核苷酸变化的突变。两种抗性生物型在密码子106处均表现出CAA到ACA的核苷酸变化，这预测脯氨酸到苏氨酸的氨基酸变化（Pro-106-Thr）。此外，R1生物型在密码子100处也有一个突变，其中发生了T对G的核苷酸取代（GCT到TCT），导致丝氨酸取代丙氨酸（Ala-100-Ser）。了解草甘膦抗性的分子机制将有助于设计有效的管理策略来控制入侵杂草。
