Effect of two satellite RNAs on Nicotiana glutinosa infected with Cucumber mosaic virus (CMV)

Two types of satellite RNAs (XJs1 and XJs2) were found to be associated with the two Cucumber mosaic virus (CMV) beet isolates XJ1 and XJ2 consisting of 384 nucleotides and 336 nucleotides, respectively. Our work showed that XJs1 and XJs2 could attenuate symptoms on Nicotiana glutinosa induced by CMV and the effect of XJs1 on symptoms was stronger than XJs2. Co-inoculation of CMV with XJs1 produced lighter oxidative stress than that with XJs2. Oxygen uptake rates through the alternative pathway in leaves infected with CMV and XJs2 were always higher than that with CMV and XJs1 and lower than infection with CMV alone. The non-photochemical fluorescence quenching (qN) increased more in N. glutinosa infected with CMV and XJs2 than that with CMV and XJs1. The relationship among helper virus, satRNAs and the host plants is discussed. Two closely-related satRNAs from the same plant has not been reported so far. The effects of these two satRNAs on virus-infected N. glutinosa were significantly different. The difference may be caused by deletion and mutation of the satRNAs.