Table 2.

Susceptibility of transgenic tobacco plants expressing the active site mutant PAP (E176V) to PVX infection

Plant line	PAP expressed	PAP* ng/mg	No. of lesions†	% infected‡
WT		0	77  ±  4	90
26139-19	PAP-v	5.6 ± 2.6	0§	30§
33617-11	PAP	0.6 ± 0.02	0§	40¶
144-1	E176V	43.8 ± 4.8	78  ±  5	100
144-7	E176V	46.2 ± 5.6	72  ±  4	100
WT		0	12  ±  2	100
26139-19	PAP-v	9.6 ± 2.6	1  ±  0.3§	30§
144-6	E176V	1,045 ± 45	11  ±  2	100
144-13	E176V	900 ± 50	13  ±  3	100

^*Twenty plants from R1 progeny of each transgenic line were analyzed ELISA for expression of PAP and PAP-positive plants were used in virus resistance tests. Mean values ± SE are shown for each transgenic line. 

^†Ten plants from each line were inoculated with 1 μg/ml PVX (top rows) or 0.5 μg/ml PVX (bottom rows) and the number of lesions were counted 9 days postinoculation (dpi). Mean values ± SE of the mean for the numbers of lesions per plant are shown. 

^‡Three leaf disks were taken from first, second, and third systemically infected leaves at 12 dpi, and viral antigen levels were quantitated by ELISA. 

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

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