莱氏野村菌紫外线诱变抗敌敌畏菌株的生理特性

Physiological characteristics of the anti-dichlorvos Nomuraea rileyi strains by UV mutagenized

摘要:

【背景】夜蛾科害虫易对化学杀虫剂产生高抗性，但一些化学农药可以对部分虫生真菌的毒力作用效果起增幅作用，目前缺乏对莱氏野村菌(Nomuraea rileyi)的该方面研究。【目的】探究对常用有机磷杀虫剂敌敌畏具有较强耐药性的紫外线诱变莱氏野村菌突变菌株的生理特性，包括菌丝生长、产孢情况和产几丁质酶活性。【方法】在紫外线诱变莱氏野村菌结合药剂驯化筛选出的突变株Nr-UVY1和Nr-UVY6基础上，以添加不同含量敌敌畏的平板培养基对突变株进行菌丝生长抑制率、继代产孢量、几丁质酶活性测定。【结果】在含1 291 mg/L敌敌畏的培养基上，敌敌畏对出发菌株菌丝生长抑制率达到100%，突变株Nr-UVY1 (42.38%)和Nr-UVY6 (37.01%)均远低于出发菌株。处理浓度大于1 291 mg/L时，2株突变株的菌丝生长抑制率曲线平稳上升且远低于出发菌株，说明突变株对敌敌畏的抗药性显著且稳定。在各浓度敌敌畏含量的培养基上，突变株Nr-UVY6得到的菌丝抑制率均小于Nr-UVY1，说明突变株Nr-UVY6对敌敌畏的抗药性更强。在同样的培养条件下，2株突变株的开始产孢时间略迟于出发菌株。突变株各代的产孢量均明显高于出发菌株，尤其是突变株Nr-UVY6各代的产孢量始终高于出发菌株2倍以上且更稳定。透明圈法测定几丁质酶活性，突变株Nr-UVY6高于Nr-UVY1和出发菌株。【结论】筛选出的经过紫外线诱变的突变菌株对敌敌畏的抗性远高于出发菌株，在生长和繁殖方面表现出更优秀的性状，并且由于其几丁质酶的活性高，可进一步探究其致病性。

Abstract:

[Background] Injurious insect (Noctuidae) tend to develop high resistance to chemical pesticides, some of them can increase the effect of some entomogenous fungi. There is a lack of research on Nomuraea rileyi in this part currently. [Objective] To explore the physiological characteristics of UV- mutant Nomuraea rileyi mutants, which are highly resistant to dichlorvos, a common organophosphate insecticide, including mycelial growth, sporulation and the activity of chitin enzyme. [Methods] Based on the mutant strains Nr-UVY1 and Nr-UVY6, which were screened by UV-induced mutagenesis of Nomuraea rileyi, the mycelial growth inhibition rate, the subculture sporulation amount, and the chitinase activity were measured by the addition of different concentrations of dichlorvos growth medium. [Results] On the medium containing 1 291 mg/L dichlorvos, the inhibition rate of dichlorvos on the mycelial growth of the original strain reached 100%, and the mutant Nr-UVY1 (42.38%) and Nr-UVY6 (37.01%) were far away lower than the original strain. According to the mycelial growth inhibition rate curve, when the treatment concentration was higher than 1 291 mg/L, the curves of the two mutant strains increased steadily and were much lower than the original strain, indicating that the resistance of the mutant strains to dichlorvos was remarkable and stable. On the medium with different concentrations of dichlorvos, the mycelial inhibition rate of the mutant strain Nr-UVY6 was smaller than that of the mutant strain Nr-UVY1, manifesting Nr-UVY6 was more resistant to dichlorvos. On the same culture conditions, the initial sporulation time of the two mutant strains was slightly later than the original strain, but the difference was not significant. The sporulation of the mutants was significantly higher than that of the original strains in each generation. In particular, the sporulation of Nr-UVY6 was always more than 2 times higher than the original strain and more stable. The chitinase activity measured by the transparent circle method, the mutant strain Nr-UVY6 was higher than Nr-UVY1 and the starting strain. [Conclusion] The mutant strains subjected to ultraviolet mutagenesis have much higher resistance to dichlorvos than the original strains, and exhibit better traits in growth and reproduction, and it is possible to further explore their level of pathogenicity due to their high activity of chitinase enzyme.