• Powdery mildew is the main disease affecting cucumber cultivation and causes severe economic loss. So far, research on cucumber resistance to powdery mildew has not yielded feasible solutions.
• This study selected two inbred cucumber lines, XY09‐118 (resistant) and Q10 (susceptible) and investigated their responses to powdery mildew infection (harvested 24 and 48 h after inoculation) using RNA sequencing.
• More than 20,000 genes were detected in cucumber leaves both with and without powdery mildew infection at the above two time points. Among these, 5478 genes were identified as differently expressed genes (DEGs) between XY09‐118 and Q10. Based on the databases GO and KEGG, the functions of DEGs were analysed. Moreover, the complex regulatory network for powdery mildew resistance was assessed, which involves plant hormone signal transduction, phenylpropanoid biosynthesis, plant–pathogen interaction and the MAPK signalling pathway. In particular, genes encoding WRKY, NAC and TCP were highlighted. In addition, genes involved in plant hormone biosynthesis, metabolism and signal transduction, pathogen resistance and abiotic stress response were analysed. Co‐expression analysis indicated that the transcription factors correlated with plant hormone signal pathway and metabolism, defence and abiotic response. The expression of several genes was validated by qRT‐PCR. The pathogen resistance regulatory network was identified by comparing resistant and susceptible inbred lines infected with powdery mildew.
• The transcriptome data provide novel insights into cucumber response to powdery mildew infection and the identified pathogen resistance genes will be highly useful for breeding efforts to enhance the resistance of cucumber to powdery mildew.

中文翻译：

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转录组分析分析显示感染白粉病的黄瓜叶片有明显的抗性反应

• 白粉病是影响黄瓜种植的主要病害，并造成严重的经济损失。迄今为止，关于黄瓜抗白粉病的研究尚未找到可行的解决方案。
• 这项研究选择了两个自交系黄瓜系XY09-118（抗性）和Q10（易感），并使用RNA测序研究了它们对白粉病感染的反应（接种后24和48 h收获）。
• 在上述两个时间点，在有和没有白粉病感染的黄瓜叶片中都检测到超过20,000个基因。其中，有5478个基因被确定为XY09-118和Q10之间的差异表达基因（DEG）。基于数据库GO和KEGG，分析了DEG的功能。此外，评估了白粉病抗性的复杂调控网络，其中涉及植物激素信号转导，苯丙烷类生物合成，植物-病原体相互作用和MAPK信号通路。特别是，突出显示了编码WRKY，NAC和TCP的基因。此外，分析了参与植物激素生物合成，代谢和信号转导，病原体抗性和非生物胁迫反应的基因。共表达分析表明，转录因子与植物激素信号通路和代谢，防御和非生物反应有关。通过qRT-PCR验证了多个基因的表达。通过比较感染白粉病的抗性和易感近交系来鉴定病原体抗性调控网络。
• 转录组数据为黄瓜对白粉病感染的反应提供了新的见解，并且鉴定出的病原体抗性基因将对提高黄瓜对白粉病的抗性的育种工作非常有用。