Cytokinin receptor CRE1 is required for the defense response of Nicotiana tabacum to Chilli veinal mottle virus

Abstract

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.