The N protein of Tomato spotted wilt virus (TSWV) is associated with the induction of programmed cell death (PCD) in Capsicum chinense plants, a hypersensitive host to TSWV infection.
In sweet pepper, the Tsw gene, originally described in Capsicum chinense, has been widely used as an efficient gene for inducing a hypersensitivity response (HR) derived Tomato spotted wilt virus (TSWV) resistance. Since previously reported studies suggested that the TSWV-S RNA mutation(s) are associated with the breakdown of Tsw mediated TSWV resistance in peppers, the TSWV genes N (structural nucleocapsid protein) and NS(S) (non-structural silencing suppressor protein) were cloned into a Potato virus X (PVX)-based expression vector, and inoculated into the TSWV-resistant C. chinense genotype, PI 159236, to identify the Tsw-HR viral elicitor. Typical HR-like chlorotic and necrotic lesions followed by leaf abscission were observed only in C. chinense plants inoculated with the PVX-N construct. Cytopathological analyses of these plants identified fragmented genomic DNA, indicative of programmed cell death (PCD), in mesophyll cell nuclei surrounding PVX-N-induced necrotic lesions. The other constructs induced only PVX-like symptoms without HR-like lesions and there were no microscopic signs of PCD. The mechanism of TSWV N-gene HR induction is apparently species specific as the N gene of a related tospovirus, Tomato chlorotic spot virus, was not a HR elicitor and did not cause PCD in infected cells.
Lovato
Fernanda Antinolfi
FA
Instituto de Biologia, Universidade de Brasília, 70910-900 Brasília, DF, Brazil.
Inoue-Nagata
Alice Kazuko
AK
Nagata
Tatsuya
T
de Avila
Antônio Carlos
AC
Pereira
Luiz Alfredo Rodrigues
LA
Resende
Renato Oliveira
RO
D017209:Apoptosis; D002212:Capsicum / Q000821:virology*; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics; D054884:Host-Pathogen Interactions; D018551:Solanum lycopersicum / Q000821:virology*; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000821:virology*; D017863:Potexvirus / Q000235:genetics / Q000378:metabolism; D017865:Tospovirus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism
D019590:Nucleocapsid Proteins; D017361:Viral Nonstructural Proteins