Deng Wei, Duan Zhiwen, Li Yang, Peng Cheng, Yuan Shuzhong
College of Plant Protection, Yangzhou University, Yangzhou 225009, China.
Plants (Basel). 2022 Nov 23;11(23):3199. doi: 10.3390/plants11233199.
Glyphosate is a non-selective herbicide and is widely used for weed control in non-cultivated land in China. One susceptible (S) and five putative glyphosate-resistant (R1, R2, R3, R4, and R5) biotypes were selected to investigate their resistance levels and the potential resistance mechanisms. Based on the dose-response assays, the R3 and R5 biotypes showed a low-level (2.4 to 3.5-fold) glyphosate resistance, and the R1, R2, and R4 biotypes exhibited a moderate- to high-level (8.6 to 19.2-fold) resistance, compared with the S biotype. The analysis of the target-site resistance (TSR) mechanism revealed that the P106A mutation and the heterozygous double T102I + P106S mutation were found in the R3 and R4 biotypes, respectively. In addition, the similar EPSPS gene overexpression was observed in the R1, R2, and R5 biotypes, suggesting that additional non-target-site resistance (NTSR) mechanisms may contribute to glyphosate resistance in R1 and R2 biotypes. Subsequently, an RNA-Seq analysis was performed to identify candidate genes involved in NTSR. In total, ten differentially expressed contigs between untreated S and R1 or R2 plants, and between glyphosate-treated S and R1 or R2 plants, were identified and further verified with RT-qPCR. One ATP-binding cassette (ABC) transporter gene, one aldo-keto reductases (AKRs) gene and one cytochrome P450 monooxygenase (CytP450) gene were up-regulated in R1 or R2 plants. These results indicated that EPSPS overexpression, single or double mutation was a common TSR mechanisms in . Additional NTSR mechanisms could play an essential role in glyphosate resistance. Three genes, ABCC4, AKR4C10, and CYP88, could serve as important candidate genes and deserve further functional studies.
草甘膦是一种非选择性除草剂，在中国广泛用于非耕地的杂草防治。选取了一个敏感（S）生物型和五个假定的抗草甘膦（R1、R2、R3、R4和R5）生物型，以研究它们的抗性水平和潜在的抗性机制。基于剂量反应试验，与S生物型相比，R3和R5生物型表现出低水平（2.4至3.5倍）的草甘膦抗性，而R1、R2和R4生物型表现出中高水平（8.6至19.2倍）的抗性。对靶标位点抗性（TSR）机制的分析表明，在R3和R4生物型中分别发现了P106A突变和杂合双T102I + P106S突变。此外，在R1、R2和R5生物型中观察到相似的5-烯醇丙酮酰莽草酸-3-磷酸合酶（EPSPS）基因过表达，表明额外的非靶标位点抗性（NTSR）机制可能导致R1和R2生物型对草甘膦产生抗性。随后，进行了RNA测序（RNA-Seq）分析，以鉴定参与NTSR的候选基因。总共鉴定出未处理的S与R1或R2植物之间以及草甘膦处理的S与R1或R2植物之间的10个差异表达重叠群，并用逆转录定量聚合酶链反应（RT-qPCR）进一步验证。一个ATP结合盒（ABC）转运蛋白基因、一个醛酮还原酶（AKR）基因和一个细胞色素P450单加氧酶（CytP450）基因在R1或R2植物中上调。这些结果表明，EPSPS过表达、单突变或双突变是常见的TSR机制。额外的NTSR机制可能在草甘膦抗性中起重要作用。三个基因，ABCC4、AKR4C10和CYP88，可作为重要的候选基因，值得进一步进行功能研究。
