Abstract: Thaumatin-like proteins, which belong to the pathogenesis-related protein 5 family, are an important part of plant defence responses. In this study, five full-length cDNAs encoding thaumatin-like protein (PnTLP1–PnTLP5) were isolated from Panax notoginseng by rapid amplification of cDNA ends. A quantitative real-time PCR analysis indicated that the PnTLP expression levels were regulated by ethylene, salicylic acid, methyl jasmonate, and H2O2. Additionally, the PnTLP expression levels were up-regulated by an Alternaria panax infection, peaking at 4 h post-inoculation. Moreover, the PnTLP2-GFP fusion protein was localised in the cell wall of onion inner epidermal cells. Furthermore, the recombinant PnTLP2 protein produced in Escherichia coli exhibited antifungal activities against Alternaria panax and A. alternata. Similarly, the overexpression of PnTLP2 in transgenic tobacco enhanced the resistance to A. panax. These results suggest that PnTLP genes are defence-related genes expressed in P. notoginseng in response to an A. panax infection.

中文翻译：

---

三七的索马甜蛋白基因赋予三七抗性

摘要：类奇异果甜蛋白属于发病相关蛋白 5 家族，是植物防御反应的重要组成部分。在本研究中，通过 cDNA 末端的快速扩增，从三七中分离出五种编码类奇异果甜蛋白 (PnTLP1–PnTLP5) 的全长 cDNA。实时定量 PCR 分析表明 PnTLP 表达水平受乙烯、水杨酸、茉莉酸甲酯和 H2O2 的调节。此外，PnTLP 表达水平被 Alternaria panax 感染上调，在接种后 4 小时达到峰值。此外，PnTLP2-GFP 融合蛋白定位于洋葱内表皮细胞的细胞壁中。此外，在大肠杆菌中产生的重组 PnTLP2 蛋白表现出对 Alternaria panax 和 A. alternata 的抗真菌活性。相似地，PnTLP2在转基因烟草中的过表达增强了对三七的抗性。这些结果表明 PnTLP 基因是在三七中表达的防御相关基因，以响应 A. panax 感染。