Involvement of PHYB in resistance to Cucumber mosaic virus in Nicotiana tabacum

Abstract

Plants are exposed to a diversity of environmental stresses throughout their life cycles and need to constantly regulate their developmental and physiological processes to respond various external stimuli. It is well known that the interaction between light and plant defence is multifaceted and complicated. Here, the recombinant vector pRNAi-LIC-PHYB was used for achieving tobacco (Nicotiana tabacum) PHYB defective mutant via the Agrobacterium-mediated transformation method. Furthermore, we investigated molecular and physiological principles in PHYB defective N. tabacum plants in response to Cucumber mottle virus (CMV) infection. Our results indicated that PHYB defective plants were more susceptible to CMV infection. There were higher viral replication level, more impetuous viral symptoms and more serious stress damages in PHYB defective mutants along the time going when compared with wild-type (wt) plants. Moreover, the transcripts of defence-related genes and activities of antioxidant enzymes in phyB mutants were down-regulated when compared with wt plants after CMV infection. Overall, our results provided new information about the molecular link between PHYB and plant immune system in N. tabacum.