Analysis of the spatial distribution of identical and two distinct virus populations differently labeled with cyan and yellow fluorescent proteins in coinfected plants.

ABSTRACT Apple latent spherical virus (ALSV) expressing yellow and cyan fluorescent proteins (ALSV-YFP and ALSV-CFP) was used to investigate the distribution of identical virus populations in coinfected plants. In Chenopodium quinoa plants inoculated with a mixture of ALSV-YFP and ALSV-CFP, fluorescence from YFP and CFP was always distributed separately in both inoculated and upper uninoculated leaves. Inoculation of each ALSV-YFP and ALSV-CFP to different leaves of a C. quinoa plant resulted in the separate distribution of each virus population among different upper leaves. When C. quinoa leaves were first inoculated with ALSV-CFP and then ALSV-YFP was reinoculated into the same leaves at various times after the first inoculation, ALSV-YFP infected only tissues where ALSV-CFP infection had not been established. The spatial separation was also found in Nicotiana benthamiana leaves coinoculated with Bean yellow mosaic virus (BYMV)-YFP and BYMV-CFP. In contrast, both YFP and CFP fluorescence signals were observed in the same tissues of N. benthamiana leaves mixed infected with ALSV-YFP and BYMV-CFP. YFP fluorescence from ALSV-YFP in mixed-infected leaves was brighter and longer than in leaves infected with ALSV-YFP singly.