Primary Analysis Of Protein Profiles In Nicotiana-TMV Interaction Under High-Temperature Stress

In this experiment,symptom masking of TMV-inoculated Nicotiana tabacum under high temperature stress ,and its possible mechanism were analyzed.The results revealed that high-temperature stress could cause a 18-30d of longer latent-period, decrease disease severity and growth promotion.However,the symptom under high-temperature stress was not masked completely. Strikingly,a nonmasaic necrotic stripe emerged only on the high-temperature stressed TMV-inoculated leaf and its adjacent leaves,but not on all the three check-plants. This live oak leaf-like necrotic stripe was consistent with symptom masking, meaning that the host-TMV interaction and host antiviral mechanism were both impacted by high-temperature stress. In spite of the slight mosaic on the topper leaves,the necrotic stripe probably be a virus infection-derived and high-temperature-dependent characteristic of host resistance,not a diseased symptom.Ester isoenzymes PAGE assay performed previously confirmed that High-temperature stress can not cause any genetic mutation. To survey whether TMV infectious capability,viron accumulation and transmission in planta were changed by high-temperature stress, the re-inoculation assay with reclaimed TMV,SDS-PAGE of TMV CP minipurification and gold-labeled TMV CP serological detection were performed.The results showed that there was equivalent TMV CP concentration in stressed and unstressed leaf,and no significant difference in TMV infectious capability.it suggested that host resistance elicitation was possibly involved in high-temperature-induced host recovery.To survey specific proteins involved in symptom masking and underlay the base of future research, several methods for protein extraction were compared.According to the protein concentration,purity and SDS-PAGE resolution band, three optimum methods including phenol extraction,PEG fraction extraction and KCl-TE fraction extraction were suitable to analyze tobacco protein. Among of them,phenol extraction with advantages of more total protein products,higher purity and better resolution band ,was selected for protein profile assay of symptom masking.SDS-PAGE showed that one 66kD and 80kD protein,in TMV-inoculated half, its opposite half and control leaf, elicited by high-temperature stress maybe members of HSP₇₀ families.As well,in symptom masked plants there is one 29kD(ca.) protein with higher density than control,suggesting an elicited host defense-related gene expression.The new 29kD(ca.) protein may be member of PR-3 group.Strikingly, the 20kD(ca.) proteins had higher density in symptom masked leaves than in both controls. These proteins with higher density should be analyzed in future research.