“…For Potato virus Y infection, NPQ was reported to be the most useful fluorescence parameter for assessing the viral effect, but no changes showed up in NPQ before the appearance of viral symptoms (Spoustová et al, 2013). However, in Pepper mild mottle virus (PMMoV)–infected N. benthamiana plants, the changes in NPQ were detected in both symptomatic and asymptomatic leaves (Barón et al, 2016), and Tobacco mosaic virus infection triggered a presymptomatic rise in Chl fluorescence intensity in tobacco (Chaerle et al, 2004). In our research, we found that ETR, NPQ , F v / F m , and qP were affected in both symptomatic and asymptomatic leaves, during infection by both TYLCCNV A and TYLCCNV A + β, with the coinfection of DNAβ bringing more severe damages to plants’ photosynthesis efficiency.…”