Yu Yongbo, Yin Yunhan, Jiang Yuying, Zhao Juyong, Ma Lifeng, Li Zhiao, Chen Qiumin, Meng Xiangnan, Fan Haiyan
College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, China.
Liaoning Academy of Agricultural Sciences, Shenyang, China.
Physiol Plant. 2025 May-Jun;177(3):e70350. doi: 10.1111/ppl.70350.
Powdery mildew, caused by Podosphaera xanthii, poses a significant threat to cucumber production. Appropriate suppression of TARGET OF RAPAMYCIN (TOR) activity confers beneficial effects on cucumber resistance to P. xanthii. TOR serves as a core modulator essential for plant growth, development, and stress resistance. However, the molecular mechanisms underlying its role in plant immunity remain poorly understood. In this study, cucumber seedlings were treated with AZD8055, a TOR-specific inhibitor, and subsequently challenged with P. xanthii. Transcriptomic analysis revealed that TOR inhibition altered several key pathways, including phenylpropanoid biosynthesis, hormone signal transduction, plant-pathogen interaction, and MAPK signaling. Upon P. xanthii attack, TOR inhibition mobilized unique molecular players associated with cell wall modification, redox state, abscisic acid (ABA) signaling, gene transcription regulation, and respiratory burst. Notably, the expression of basic Helix-Loop-Helix 35 (bHLH35) and FCS-Like Zinc finger 15 (FLZ15) was induced during P. xanthii infection. Moreover, silencing bHLH35/FLZ15 decreased cucumber tolerance to P. xanthii stress. Overall, bHLH35 and FLZ15 likely drive immune function due to the action of TOR. Our findings elucidate the molecular events by which TOR modulates plant disease resistance in P. xanthii-infected cucumbers.
由黄色单囊壳白粉菌（Podosphaera xanthii）引起的白粉病对黄瓜生产构成重大威胁。适度抑制雷帕霉素靶蛋白（TOR）的活性对黄瓜抗黄色单囊壳白粉菌具有有益作用。TOR是植物生长、发育和抗逆所必需的核心调节因子。然而，其在植物免疫中作用的分子机制仍知之甚少。在本研究中，用TOR特异性抑制剂AZD8055处理黄瓜幼苗，随后用黄色单囊壳白粉菌进行挑战。转录组分析表明，TOR抑制改变了几个关键途径，包括苯丙烷类生物合成、激素信号转导、植物-病原体相互作用和丝裂原活化蛋白激酶（MAPK）信号传导。在黄色单囊壳白粉菌攻击后，TOR抑制调动了与细胞壁修饰、氧化还原状态、脱落酸（ABA）信号传导、基因转录调控和呼吸爆发相关的独特分子参与者。值得注意的是，在黄色单囊壳白粉菌感染期间，碱性螺旋-环-螺旋35（bHLH35）和类FCS锌指15（FLZ15）的表达被诱导。此外，沉默bHLH35/FLZ15会降低黄瓜对黄色单囊壳白粉菌胁迫的耐受性。总体而言，由于TOR的作用，bHLH35和FLZ15可能驱动免疫功能。我们的研究结果阐明了TOR调节黄色单囊壳白粉菌感染黄瓜中植物抗病性的分子事件。
