Fig. 2.

(A) Symptom expression in C. chinense PI152225 and C. annuum S3669 mechanically inoculated with Tomato spotted wilt virus (TSWV)-Pap: PI152225 plants maintained at 25 ± 2°C developed necrotic spots on inoculated leaves, while plants maintained at 30 ± 2°C formed necrotic spots moving upward from leaf to leaf (non-self-limiting HR). HR reaction was observed in leaves of inoculated S3669 plants maintained at 25 ± 2°C, while systemic infection was observed in plants at 30 ± 2°C. (B) Detection of TSWV RNA by northern blot hybridization. Total RNA was extracted from the upper leaves of C. chinense PI152225 and C. annuum S3669 maintained at 25 ± 2°C and 30 ± 2°C at 10 dpi with TSWV-Pap. Five plants of each species were used for total RNA extraction. RNA was fractionated by agarose gel electrophoresis, blotted to nitrocellulose membranes, and hybridized with the specified digoxigenin-labeled RNA probes for TSWV NSm (PC = positive control; NC = negative control). PI152225 2nd, 3rd, and 4th plants, and S3669 from 2nd to 5th plants, maintained at 30 ± 2°C, revealed TSWV-specific bands, while plants maintained at 25 ± 2°C did not exhibit TSWV-specific bands.