Department of Crop Sciences, Division of Plant Pathology and Crop Protection, Georg-August Universität Göttingen, Göttingen 37077, Germany.
CropScience Division, Bayer AG, Frankfurt/Main 65926, Germany.
Plant Physiol. 2024 Oct 1;196(2):1254-1267. doi: 10.1093/plphys/kiae330.
Resistance to preemergence herbicides, e.g. inhibitors of the biosynthesis of very-long-chain fatty acids (VLCFAs), is evolving in response to increased use of these compounds. Grass weeds such as ryegrasses (Lolium spp.) have accumulated resistance to various herbicide modes of action. Here, an RNA-seq analysis was conducted using 3 ryegrass populations resistant to the VLCFA biosynthesis inhibitor flufenacet to investigate this phenomenon. Besides various transcripts, including putative long noncoding RNAs (lncRNAs), a single putatively functional tau class glutathione transferase (GST) was constitutively differentially expressed. It was further induced by herbicide application. This GST was expressed as a recombinant protein in Escherichia coli along with other GSTs and detoxified flufenacet rapidly in vitro. Detoxification rates of other herbicides tested in vitro were in accordance with cross-resistance patterns previously determined in vivo. A genome-wide GST analysis revealed that the candidate GST was located in a cluster of 3 intronless GSTs. Their intronless nature possibly results from the retroposition of cellular mRNAs followed by tandem duplication and may affect gene expression. The large number of GSTs (≥195) in the genome of rigid ryegrass (Lolium rigidum) compared with other plant organisms is likely a key factor in the ability of this weed to evolve resistance to different herbicide chemistries. However, in the case of flufenacet resistance, a single upregulated GST with high affinity for the substrate flufenacet possibly contributes overproportionally to rapid herbicide detoxification in planta. The regulation of this gene and the role of differentially expressed transcripts, including various putative lncRNAs, require further investigation.
抗萌发期除草剂的抗性，例如非常长链脂肪酸（VLCFA）生物合成抑制剂，是对这些化合物使用增加的响应而进化的。黑麦草（Lolium spp.）等禾本科杂草已经积累了对各种除草剂作用模式的抗性。在这里，使用对 VLCFA 生物合成抑制剂氟噻草胺具有抗性的 3 个黑麦草种群进行了 RNA-seq 分析，以研究这种现象。除了各种转录本，包括假定的长非编码 RNA（lncRNA）外，还存在一个单一的假定功能的 tau 类谷胱甘肽 S-转移酶（GST）持续差异表达。它进一步被除草剂的应用诱导。该 GST 与其他 GST 一起在大肠杆菌中表达为重组蛋白，并在体外快速解毒氟噻草胺。在体外测试的其他除草剂的解毒率与体内先前确定的交叉抗性模式一致。全基因组 GST 分析表明，候选 GST 位于无内含子 GST 簇中。它们无内含子的性质可能是由于细胞 mRNA 的反转录，随后是串联重复，可能影响基因表达。与其他植物生物相比，硬黑麦草（Lolium rigidum）基因组中大量的 GST（≥195）可能是这种杂草进化对不同除草剂化学物质抗性的关键因素。然而，在氟噻草胺抗性的情况下，一个对底物氟噻草胺具有高亲和力的单个上调 GST 可能对植物体内快速除草剂解毒起不成比例的作用。该基因的调控以及差异表达转录本（包括各种假定的 lncRNA）的作用需要进一步研究。
