Wang Jingjing, Chen Jingchao, Li Xiangju, Li Dan, Li Zheng, Cui Hailan
Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Front Plant Sci. 2020 Sep 30;11:572610. doi: 10.3389/fpls.2020.572610. eCollection 2020.
American sloughgrass ( Steud.) is one of the most troublesome weeds infesting wheat and canola fields in China. Some biotypes cannot be controlled, either by acetolactate synthase (ALS) or acetyl coenzyme A carboxylase (ACCase) inhibitors, which are the main herbicides for controlling this weed. However, very few studies have investigated multiple resistance mechanism in . In this study, a biotype with a high resistance to ALS inhibitors we have reported was also showed relatively lower resistance to ACCase inhibitors, with a resistance index around 7. RNA-seq analysis was used to investigate the factors responsible for multiple resistance, and 60,108 unigenes were assembled by transcriptome assembly and then annotated across eight databases. A Pro-197-Ser mutation was identified in the gene by SNPs analysis and validated by PCR, while no mutation was identified in the gene. Nineteen candidate metabolic genes were screened and their overexpression was confirmed by qPCR. The expression of and in resistant plants ranged from 7.5- to 109.4-folds than that in susceptible ones at different times after two kinds of herbicide treatment. In addition, GST activities in resistant plants were 3.0-5.0 times higher than that in susceptible plants. Other novel resistance factors also showed high correlation with multiple resistance which included four genes encoding disease resistance proteins, a transcription factor (), and one gene conferring blight resistance. In this research, a biotype was confirmed to have evolved multiple resistance to ACCase and ALS inhibitors. The Pro-197-Ser mutation in gene and high-level GST activities were confirmed responsible for the multiple resistance. Characterized disease-resistance proteins, transcription factor, and blight-resistance proteins may play an essential role in these multiple herbicide resistance.
美国臂形草（Steud.）是中国小麦和油菜田中最棘手的杂草之一。一些生物型对乙酰乳酸合酶（ALS）或乙酰辅酶A羧化酶（ACCase）抑制剂均无抗性，而这两种抑制剂是防治该杂草的主要除草剂。然而，很少有研究调查其多重抗性机制。在本研究中，我们报道的一种对ALS抑制剂具有高抗性的生物型对ACCase抑制剂的抗性相对较低，抗性指数约为7。采用RNA测序分析来研究多重抗性的相关因素，通过转录组组装得到60108个单基因，并在八个数据库中进行注释。通过单核苷酸多态性（SNP）分析在该基因中鉴定出一个Pro-197-Ser突变，并通过聚合酶链反应（PCR）进行验证，而在该基因中未鉴定到突变。筛选出19个候选代谢基因，并通过定量聚合酶链反应（qPCR）证实了它们的过表达。在两种除草剂处理后的不同时间，抗性植株中这些基因的表达量比敏感植株高7.5至109.4倍。此外，抗性植株中的谷胱甘肽S-转移酶（GST）活性比敏感植株高3.0至5.0倍。其他新的抗性因素也与多重抗性高度相关，其中包括四个编码抗病蛋白的基因、一个转录因子（）和一个赋予抗枯萎病能力的基因。在本研究中，一种生物型被证实对ACCase和ALS抑制剂产生了多重抗性。该基因中的Pro-197-Ser突变和高水平的GST活性被证实是多重抗性的原因。具有特征性的抗病蛋白、转录因子和抗枯萎病蛋白可能在这些多重除草剂抗性中起重要作用。
