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

Virus Res. 2008 Nov;137(2):245-52. doi: 10.1016/j.virusres.2008.07.020. Epub 2008 Sep 5.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis*
  • Capsicum / virology*
  • Gene Expression
  • Genetic Vectors / genetics
  • Host-Pathogen Interactions
  • Nucleocapsid Proteins / genetics
  • Nucleocapsid Proteins / metabolism*
  • Plant Diseases / virology*
  • Potexvirus / genetics
  • Potexvirus / metabolism
  • Solanum lycopersicum / virology*
  • Tospovirus / genetics
  • Tospovirus / pathogenicity
  • Tospovirus / physiology*
  • Viral Nonstructural Proteins / genetics
  • Viral Nonstructural Proteins / metabolism

Substances

  • Nucleocapsid Proteins
  • Viral Nonstructural Proteins