Table 3.

Susceptibility of transgenic tobacco plants expressing the C-terminal deletion mutant (W237Stop) to PVX infection

Plant line	PAP expressed	Level of PAP,* ng/mg	No. of lesions†	% of plants showing systemic infection‡
				12 dpi	21 dpi
WT		0	62 ± 10	80	80
26139-19	PAP-v	9.6	21 ± 8§	30¶	30¶
147-27	W237Stop	2.0	24 ± 6§	30¶	30¶
147-19	W237Stop	3.8	10 ± 3§	70	70
WT		0	24 ± 5	90	90
26139-19	PAP-v	9.6	1 ± 0.6§	10§	30§
33617-11	PAP	1.6	11 ± 1§	10§	40¶
144-12-13	E176V	1,500	23 ± 4	100	100
147-19-25	W237Stop	3.8	12 ± 3¶	20§	60
145-13-19	W237Stop	4.4	6 ± 1§	30§	60

dpi, Days postinoculation. 

^*PAP levels were quantitated by ELISA in the primary transgenic plants. Only PAP-positive plants were used in virus resistance tests. 

^†Ten plants from progeny (top rows, R1 generation; bottom rows, R2 generation) of each transgenic line were inoculated with 50 μl of 1 μg/ml PVX (top rows) or 0.5 μg/ml PVX (bottom rows) on two leaves per plant. The number of lesions were counted 12 dpi. Mean values ± SE of the mean are shown for the number of lesions per plant. The results are from two representative experiments that were repeated three times with similar results. 

^‡Two leaf disks were taken from first and second systemically infected leaf from each plant at 12 dpi, and two leaf disks were taken from third and fourth systemically infected leaf at 21 dpi. Viral antigen levels were quantitated by ELISA. 

^§Significantly different from wild type at 1% level. 

^¶Significantly different from wild type at 5% level.