耐三唑并嘧啶类除草剂花生种质创制与鉴定

At present, the germplasm resources of herbicide-tolerant peanuts are scarce, which restricts the diversified development of peanut cultivation patterns. In order to create peanut germplasm resources that are tolerant to different herbicides, we used ethyl methanesulfonate mutagenesis technology to create a mutagenized population consisting of more than 55,000 peanut lines. Subsequently, a variety of different herbicides were selected to screen this population, and multiple peanut mutants with tolerance to different herbicides were obtained. One of the mutants showed extremely strong tolerance to flumetsulam and florasulam in both field foliar spray treatment and herbicide tolerance evaluation tests under various laboratory conditions, but this tolerance trait did not have an adverse impact on the yield and quality of peanuts. In order to determine whether this trait is associated with herbicide target resistance, we compared and analyzed the differences in the gene sequences and expression levels of these two herbicide target enzymes (acetohydroxyacid synthase, AHAS) in the mutant and the wild type. Molecular cloning and sequence analysis showed that there is one gene on peanut chromosomes A10 and B10 that is highly similar to the Arabidopsis AtAHAS sequence, named AhAHAS1a and AhAHAS1b respectively. There is also one AHAS gene on peanut chromosomes A08 and B08 respectively, named AhAHAS2a and AhAHAS2b. However, compared with the wild type, there were no nucleotide substitutions in these genes in the mutant that could cause changes in the amino acid sequence. It was further found that there was no significant difference in the expression level of the AhAHAS gene between the mutant and the wild type. These results indicate that the herbicide tolerance of this peanut mutant may be caused by a non-target resistance mechanism.

目前耐除草剂花生的种质资源匮乏,这制约了花生栽培模式的多元化发展。为创制耐不同除草剂的花生种质资源,我们利用甲基磺酸乙酯诱变技术创建了一个由55,000多个花生株系组成的诱变群体,随后选择多种不同除草剂对该群体进行筛选,获得多个对不同除草剂具有耐性的花生突变体。其中一个突变体在田间叶面喷施处理和多种实验室条件下的除草剂耐受性评估试验中均表现出对唑嘧磺草胺和双氟磺草胺极强的耐性,但这种耐性性状并未对花生的产量与品质产生不良影响。为明确这种性状是否与除草剂靶标抗性相关联,我们比较分析了该突变体与野生型中这2种除草剂靶标酶(乙酰羟酸合酶, AHAS)的基因序列及其表达量的差异。分子克隆与序列分析显示,花生A10与B10染色体上各含一个与拟南芥AtAHAS序列高度相似的基因,分别命名为AhAHAS1a与AhAHAS1b。花生A08与B08染色体上亦各含一个AHAS基因,分别命名为AhAHAS2a与AhAHAS2b。然而,与野生型相比,突变体中的这些基因并未发生能够致使氨基酸序列发生改变的核苷酸替换。进而发现, AhAHAS基因的表达量在突变体与野生型中没有显著差异。这些结果表明,该花生突变体的除草剂耐性可能由非靶标抗性机制所致。