Department of Plant Pathology, North Dakota State University, Fargo, ND 58108.
Department of Animal Science, North Dakota State University, Fargo, ND 58105.
Phytopathology. 2019 Dec;109(12):2074-2086. doi: 10.1094/PHYTO-03-19-0105-R. Epub 2019 Nov 5.
, the causal agent of Septoria leaf spot and stem canker, is responsible for mortality and yield loss in plantations. However, little is known about the mode of infection and the mechanisms of resistance in this pathosystem. To characterize these phenomena, microscopic, biochemical, and transcriptome comparisons were performed between leaves of moderately resistant and susceptible genotypes of inoculated with conidia. Using scanning electron, cryofracture, and laser-scanning confocal microscopy, the infection and colonization of leaves by were examined across five time points (48 h, 96 h, 1 week, 2 weeks, and 3 weeks). The infection process was similar regardless of the host genotype. Differences in host colonization between susceptible and moderately resistant genotypes were apparent by 1 week postinoculation. However, the germination of conidia was greater on the susceptible than on the moderately resistant genotype ( < 0.008). Diaminobenzidine staining, a measure of hydrogen peroxide accumulation, was different ( < 0.001) between the host genotypes by 2 weeks postinoculation. Transcriptome differences between genotypes indicated that the speed and amplitude of the defense response were faster and more extensive in the moderately resistant genotype. Changes in gene expression support the microscopic and biochemical observations.
, 是导致叶斑病和茎溃疡的病原体，会导致 种植园的死亡率和产量损失。然而，对于该病原体系中的感染模式和抗性机制知之甚少。为了描述这些现象，对接种 分生孢子的中度抗性和易感基因型的叶片进行了微观、生化和转录组比较。使用扫描电子显微镜、冷冻断裂和激光共聚焦显微镜，在五个时间点（48 h、96 h、1 周、2 周和 3 周）检查了 对 叶片的感染和定殖。无论宿主基因型如何，感染过程都相似。在接种后 1 周，易感和中度抗性基因型之间的宿主定殖差异明显。然而，与中度抗性基因型相比，在易感基因型上的分生孢子萌发更大（<0.008）。二氨基联苯胺染色，衡量过氧化氢积累的一种方法，在接种后 2 周时在宿主基因型之间存在差异（<0.001）。基因型之间的转录组差异表明，在中度抗性基因型中，防御反应的速度和幅度更快、更广泛。基因表达的变化支持了微观和生化观察。
