College of Plant Protection of Gansu Agricultural University; Lanzhou, P.R. China.
Biocontrol Engineering Laboratory of Crop Diseases and Pests of Gansu Province, Lanzhou, P.R. China.
PLoS One. 2022 Feb 1;17(2):e0263068. doi: 10.1371/journal.pone.0263068. eCollection 2022.
The aim of this study was to uncover the molecular mechanism through which fungicide resistance develops in Podosphaera xanthii, a fungi that causes powdery mildew in hull-less pumpkin. Treatments of inoculated P. xanthii were carried out on leaves of hull-less pumpkin and subsequently treated with kinds of triazole fungicide for seven generations. Resistant strains of P. xanthii thus obtained were evaluated for their resistance levels. The resistance levels of the fungi to four fungicides of were high except that of the propiconazole-resistant strain, which showed moderate resistance. The F7 generations of five resistant strains thus obtained were cultured continuously for five generations without fungicide induction, and their resistance level were found to be relatively stable. The DNA of the sensitive strain and the five kinds of resistant strains were extracted by the sodium dodecyl sulfate (SDS) method and its internal transcribed spacer (ITS) region was amplified by using ITS1/ITS4 primer and specific primer F/R and they were sequenced respectively. The DNA sequence comparison of resistant and sensitive strains showed that the base pairs of tebuconazole-resistant strains and flusilazole-resistant strains were mutated, with mutation rates of 4.8% and 1.6%, respectively. The base pairs of the other three resistant strains did not change.
本研究旨在揭示无壳南瓜白粉病菌（Podosphaera xanthii）产生抗药性的分子机制。该病菌可引起无壳南瓜白粉病。将接种的 P. xanthii 处理到无壳南瓜叶片上，然后用多种三唑类杀菌剂处理 7 代。获得的抗药性 P. xanthii 菌株用于评估其抗药性水平。除了对丙环唑具有中等抗性的菌株外，该真菌对四种杀菌剂的抗性水平均较高。从五个获得的抗性菌株的 F7 代连续培养五代而不进行杀菌剂诱导，发现其抗性水平相对稳定。通过十二烷基硫酸钠（SDS）法提取敏感菌株和五种抗性菌株的 DNA，使用 ITS1/ITS4 引物和特异性引物 F/R 扩增其内部转录间隔区（ITS）区域，并分别进行测序。抗性和敏感菌株的 DNA 序列比较表明，戊唑醇抗性菌株和氟硅唑抗性菌株的碱基对发生了突变，突变率分别为 4.8%和 1.6%。其他三个抗性菌株的碱基对没有变化。
