Department of Plant Genetics, Breeding and Biotechnology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland.
Department of Botany, Institute of Biology, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland.
Int J Mol Sci. 2021 Apr 18;22(8):4192. doi: 10.3390/ijms22084192.
Bacterial angular leaf spot disease (ALS) caused by pv. () is one of the biological factors limiting cucumber open-field production. The goal of this study was to characterize cytological and transcriptomic response of cucumber to this pathogen. Plants of two inbred lines, B10 (susceptible) and Gy14 (resistant), were grown, and leaves were inoculated with highly virulent strain 814/98 under growth chamber conditions. Microscopic and transcriptional evaluations were performed at three time points: before, 1 and 3 days post inoculation (dpi). Investigated lines showed distinct response to . At 1 dpi bacterial colonies were surrounded by necrotized mesophyll cells. At 3 dpi, in the susceptible B10 line bacteria were in contact with degraded cells, whereas cells next to bacteria in the resistant Gy14 line were plasmolyzed, but apparently still alive and functional. Additionally, the level of HO production was higher in resistant Gy14 plants than in B10 at both examined time points. In RNA sequencing more than 18,800 transcripts were detected in each sample. As many as 1648 and 2755 differentially expressed genes (DEGs) at 1 dpi as well as 2992 and 3141 DEGs at 3 dpi were identified in B10 and Gy14, respectively. DEGs were characterized in terms of functional categories. Resistant line Gy14 showed massive transcriptomic response to at 1 dpi compared to susceptible line B10, while a similar number of DEGs was detected for both lines at 3 dpi. This suggests that dynamic transcriptomic response to the invading pathogen may be related with host resistance. This manuscript provides the first transcriptomic data on cucumber infected with the pathovar and helps to elucidate resistance mechanism against ALS disease.
细菌性角斑病（ALS）由 pv. （）引起，是限制黄瓜露地生产的生物学因素之一。本研究的目的是表征黄瓜对该病原体的细胞学和转录组反应。在生长室条件下，用高毒力菌株 814/98 接种两个自交系 B10（敏感）和 Gy14（抗性）的植株叶片。在三个时间点（接种前、接种后 1 天和 3 天）进行微观和转录评估。研究的品系对 表现出明显的反应。在 1 dpi 时，细菌菌落被坏死的叶肉细胞包围。在 3 dpi 时，在敏感的 B10 系中，细菌与降解的细胞接触，而在抗性 Gy14 系中，靠近细菌的细胞发生质壁分离，但显然仍然存活并具有功能。此外，在两个检查时间点，Gy14 抗性植株的 HO 产生水平均高于 B10 敏感植株。在 RNA 测序中，每个样本中检测到超过 18800 个转录本。在 B10 和 Gy14 中，分别在 1dpi 时鉴定出 1648 和 2755 个差异表达基因（DEGs），以及在 3dpi 时鉴定出 2992 和 3141 个 DEGs。根据功能类别对 DEGs 进行了描述。与敏感系 B10 相比，抗性系 Gy14 在 1dpi 时对 表现出大量的转录组反应，而在两个系中在 3dpi 时检测到的 DEGs 数量相似。这表明对入侵病原体的动态转录组反应可能与宿主抗性有关。本研究提供了黄瓜感染 pv. 后转录组的首个数据，有助于阐明对抗 ALS 病的抗性机制。
