橘全爪螨对双甲脒的抗性选育及其P450基因的表达差异分析

Selection of resistance to amitraz and analysis of expression difference of cytochrome P450 genes in Panonychus citri(Acari:Tetranychidae)

为了对双甲脒进行抗性风险评估,弄清P450基因在橘全爪螨Panonychus citri抗药性中的作用,在室内用双甲脒对橘全爪螨进行了抗性选育和交互抗性研究,同时分析了橘全爪螨双甲脒抗性和敏感品系P450基因表达差异。经过12代抗性选育,获得了橘全爪螨双甲脒抗性品系,与敏感品系比较,橘全爪螨对双甲脒的抗性倍数达到26.32倍。抗性风险评估表明,橘全爪螨对双甲脒抗性遗传力h2为0.148。螺螨酯、丁醚脲、炔螨特和三唑锡对抗性品系的LC50分别为敏感品系的16.85,4.98,2.13和2.05倍,表明双甲脒抗性品系对螺螨酯、丁醚脲、炔螨特和三唑锡具有明显的交互抗性。阿维菌素、苯丁锡、哒螨灵、矿物油对抗性品系LC50分别为敏感品系的1.10,1.21,0.67和0.99倍,表明双甲脒抗性品系对上述4种药剂没有显著的交互抗性。基因差异性分析发现,抗性品系中有16条P450基因发生了上调,27条P450基因发生了下调,其中CYP389A6上调倍数最高[log2ratio(RS/SS)=11.526],CYP389A2下调倍数最高[log2ratio(RS/SS)=-12.683],由此推断,CYP389A6上调和CYP389A2下调可能是橘全爪螨对双甲脒产生抗性的重要原因。

To evaluate the resistance risk of Panonychus citri to amitraz and clarify the relationship between expression level of cytochrome P450 gene and resistance of P.citri,resistance selection was conducted in the laboratory,and cross-resistance of the amitraz-resistant strain was studied with slide-dip method and cytochrome P450 gene expression profiles between the resistant strain and the susceptible strain were compared using RPKM（reads per kb per million reads） method.After selection with amitraz continuously for 12 generations,a resistant strain was obtained with the resistance ratio（R/S） of 26.32 compared with the susceptible strain.The realized heritability of resistance to amitraz was 0.148.Bioassay data showed that the amitraz-resistant strain had positive cross-resistance to spirodiclofen,diafenthiuron,propargite and azocyclotin（the R/S ratio was 16.85,4.98,2.13,and 2.05,respectively）,but had no cross-resistance to abamectin,fenbutatin oxide,pyridaben and petroleum oil（the R/S ratio was 1.10,1.21,0.67 and 0.99,respectively）.Gene expression difference analysis results indicated that 16 cytochrome P450 genes were up-regulated and 27 cytochrome P450 genes were down-regulated in the resistant strain.CYP389A6 [log2ratio（RS/SS）=11.526] and CYP389A2 [log2 ratio（RS/SS） =-12.683] were the top up-regulated and down-regulated genes,respectively,which are very likely to be associated with the resistance of P.citri to amitraz.