Morden Research & Development Centre, Agriculture and Agri-Food Canada, 101 Route 100, Morden, Manitoba, R6M 1Y5, Canada.
Department of Plant Pathology, College of Agriculture and Biotechnology, China Agricultural University, No. 2 Yuan Ming Yuan West Road, People's Republic of China.
Environ Microbiol. 2020 Jul;22(7):2956-2967. doi: 10.1111/1462-2920.15063. Epub 2020 Jun 2.
Reactive oxygen species (ROS) play an important role during host-pathogen interactions and are often an indication of induced host defence responses. In this study, we demonstrate for the first time that Puccinia triticina (Pt) generates ROS, including superoxide, H O and hydroxyl radicals, during wheat infection. Through pharmacological inhibition, we found that ROS are critical for both Pt urediniospore germination and pathogenic development on wheat. A comparative RNA-Seq analysis of different stages of Pt infection process revealed 291 putative Pt genes associated with the oxidation-reduction process. Thirty-seven of these genes encode known proteins. The expressions of five Pt genes, including PtNoxA, PtNoxB, PtNoxR, PtCat and PtSod, were subsequently verified using RT-qPCR analysis. The results show that the expressions of PtNoxA, PtNoxB, PtNoxR, PtCat and PtSod are up-regulated during urediniospore germination. In comparison, the expressions of PtNoxA, PtNoxB, PtNoxR and PtCat are down-regulated during wheat infection from 12 to 120 h after inoculation (HAI), whereas the expression of PtSod is up-regulated with a peak of expression at 120 HAI. We conclude that ROS are critical for the full virulence of Pt and a coordinate down-regulation of PtNox genes may be important for successful infection in wheat.
活性氧（ROS）在宿主-病原体相互作用中起着重要作用，通常是诱导宿主防御反应的指标。在本研究中，我们首次证明小麦叶锈菌（Pt）在感染小麦的过程中产生 ROS，包括超氧阴离子、H 2 O 2 和羟基自由基。通过药理学抑制，我们发现 ROS 对于 Pt 夏孢子萌发和在小麦上的致病性发育都是至关重要的。对 Pt 感染过程不同阶段的比较 RNA-Seq 分析揭示了 291 个与氧化还原过程相关的假定 Pt 基因。其中 37 个基因编码已知蛋白。随后使用 RT-qPCR 分析验证了五个 Pt 基因（PtNoxA、PtNoxB、PtNoxR、PtCat 和 PtSod）的表达。结果表明，PtNoxA、PtNoxB、PtNoxR、PtCat 和 PtSod 的表达在夏孢子萌发过程中上调。相比之下，PtNoxA、PtNoxB、PtNoxR 和 PtCat 的表达在接种后 12 至 120 小时（HAI）的小麦感染过程中下调，而 PtSod 的表达上调，在 120 HAI 时达到表达高峰。我们得出结论，ROS 对 Pt 的完全毒力至关重要，PtNox 基因的协调下调可能对在小麦中成功感染很重要。
