Li Zhiling, Li Xiangju, Cui Hailan, Zhao Guodong, Zhai Dan, Chen Jingchao
Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
School of Life Sciences, Inner Mongolia University, Hohhot, China.
Front Plant Sci. 2021 Nov 19;12:776990. doi: 10.3389/fpls.2021.776990. eCollection 2021.
Fitness is an important trait in weed species that have developed herbicide resistance, including resistance to the popular herbicide glyphosate. Fitness cost is commonly found in weeds with glyphosate resistance, which is caused by target-site mutations. In this study, the vegetative and fecundity fitness traits in a glyphosate-resistant (GR) population caused by 5-enolpyruvylshikimate-3-phosphate synthase () overexpression were investigated under glyphosate-free conditions. The results showed that the resistance index of the population resistant (R) to glyphosate compared with that of the population susceptible (WT) to it was approximately 4.0. Furthermore, expression level in the R plants was 20.1-82.7 times higher than that in the WT plants. The dry weight of the R population was significantly higher than that of the WT population at the later growth stage after planting; a similar trend was observed for leaf area. In addition, seed production in the R population was 1.4 times higher than that in the WT population. The R and WT populations showed similar maximum germination rates and T values. UPLC-MS/MS was performed for the metabolic extracts prepared from the leaves of R and WT populations to address changes in the metabolome. A total of 121 differential metabolites were identified between R and WT individuals. The levels of 6-hydroxy-1H-indole-3-acetamide and indole acetaldehyde, which are associated with auxin synthesis, were significantly higher in plants of the R population than in those of the WT population. However, some secondary metabolite levels were slightly lower in the R population than in the WT population. To conclude, in this study, vegetative and fecundity fitness benefits were found in the GR population. The results of metabolome analysis indicate that the increase in 6-hydroxy-1H-indole-3-acetamide and indole acetaldehyde levels may be the result of fitness benefit. Further studies should be conducted to confirm the functions of these metabolites.
适合度是已产生除草剂抗性的杂草物种的一个重要特性，包括对常用除草剂草甘膦的抗性。适合度代价在具有草甘膦抗性的杂草中普遍存在，这是由靶标位点突变引起的。在本研究中，在无草甘膦条件下，研究了由5-烯醇丙酮酸莽草酸-3-磷酸合酶（EPSPS）过表达导致的草甘膦抗性（GR）群体的营养和繁殖适合度特性。结果表明，与敏感（WT）群体相比，抗性（R）群体对草甘膦的抗性指数约为4.0。此外，R植株中EPSPS的表达水平比WT植株高20.1 - 82.7倍。种植后生长后期，R群体的干重显著高于WT群体；叶面积也观察到类似趋势。此外，R群体的种子产量比WT群体高1.4倍。R和WT群体表现出相似的最大发芽率和T值。对R和WT群体叶片制备的代谢提取物进行了超高效液相色谱-串联质谱（UPLC-MS/MS）分析，以研究代谢组的变化。在R和WT个体之间共鉴定出121种差异代谢物。与生长素合成相关的6-羟基-1H-吲哚-3-乙酰胺和吲哚乙醛水平在R群体植株中显著高于WT群体植株。然而，R群体中一些次生代谢物水平略低于WT群体。总之，在本研究中，GR群体在营养和繁殖适合度方面具有优势。代谢组分析结果表明，6-羟基-1H-吲哚-3-乙酰胺和吲哚乙醛水平的升高可能是适合度优势的结果。应进一步开展研究以确认这些代谢物的功能。
