As an important phytohormone, cytokinins confer resistance of plants to several fungal and bacterial pathogens. However, the discovery of cytokinins in the viral resistance of Nicotiana tabacum is seldom reported. In the current study, we obtained tobacco CRE1 (cytokinin receptor 1) deficient mutants by Agrobacterium-mediated transformation utilizing the recombinant pRNAi-LIC-CRE1. Our conclusions indicated that CRE1 deficiency increased the susceptibility of N. tabacum to Chilli veinal mottle virus (ChiVMV) infection. The CRE1 deficient mutant plants displayed both more evident ChiVMV-induced symptom and higher transcription level of viral coat protein gene compared to the wild type (WT) plants. The antioxidant metabolism was altered in CRE1 deficient plants under virus inoculation. Photosystem damages caused by virus were also more severe in CRE1 deficient mutant plants compared to that in the WT plants. Additionally, expressions of several defense-related genes induced by ChiVMV infection were repressed in CRE1 deficient plants. Taken all together, these results suggested that CRE1 is required for N. tabacum defense responses to ChiVMV infection.

中文翻译：

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烟草对辣椒静脉斑驳病毒的防御反应需要细胞分裂素受体 CRE1

作为一种重要的植物激素，细胞分裂素赋予植物对几种真菌和细菌病原体的抗性。然而，很少有报道在烟草的病毒抗性中发现细胞分裂素。在目前的研究中，我们利用重组 pRNAi-LIC-CRE1 通过农杆菌介导的转化获得了烟草 CRE1（细胞分裂素受体 1）缺陷突变体。我们的结论表明，CRE1 缺陷增加了普通烟草对辣椒静脉斑驳病毒 (ChiVMV) 感染的易感性。与野生型 (WT) 植物相比，CRE1 缺陷突变植物表现出更明显的 ChiVMV 诱导症状和更高的病毒外壳蛋白基因转录水平。在病毒接种下，CRE1 缺陷植物的抗氧化代谢发生了改变。与 WT 植物相比，病毒引起的光系统损伤在 CRE1 缺陷突变植物中也更严重。此外，在 CRE1 缺陷植物中，由 ChiVMV 感染诱导的几种防御相关基因的表达受到抑制。总之，这些结果表明 CRE1 是烟草对 ChiVMV 感染的防御反应所必需的。