Fig 7. RSV infection is inhibited in plants overexpressing UBL5.

A. N. benthamiana wild type and three transgenic lines (OE-N1, OE-N2 and OE-N3) overexpressing NbUBL5.1 were inoculated with RSV. At 7 dpi, wild-type plants showed typical yellow foci on the inoculated leaves, while no obvious infection foci appeared on leaves of transgenic plants. At 15 dpi, all wild-type plants showed typical mosaic and chlorosis on newly-emerged leaves, implying systemic infection with RSV, but on transgenic plants the systemic symptom was significantly alleviated. B. Northern blot showing that RSV RNAs accumulated at a lower level in both the inoculated and systemically infected leaves of transgenic lines. C. Wild type rice and three transgenic lines (OE-R1, OE-R2 and OE-R3) overexpressing OsUBL5 were inoculated with RSV. At 20 dpi, approximately 40% of the wild type plants were dead, while only about 25% transgenic plants had died. D. In the surviving plants, RSV symptoms on transgenic plants were significantly milder with fewer yellow streaks than on wild type plants. E. In the surviving plants, the accumulation of RSV RNAs was also less than on transgenic plants. Twenty plants were used for each of three biological repeats. Bars represent the standard errors of the means from three biological repeats. Band intensity in blots was calculated by ImageJ based on three replicates. A two-sample unequal variance directional t test was used to test the significance of the difference (**, p value<0.01).