Tobacco mosaic virus regulates the expression of its own resistance gene N.
The N gene of tobacco (Nicotiana tabacum) is a typical resistance (R) gene engendering localization of tobacco mosaic virus (TMV) infection and the elicitation of a hypersensitive necrotic response. The consensus model for R gene-derived resistance is at the level of protein:protein interactions, in which proteins of the pathogen interact with already present receptor-like proteins produced by the plant's R genes. This article demonstrates, by quantitative real-time reverse transcription-PCR analysis, that in tobacco carrying the dominant allele N, a basal level of transcription indeed occurs in noninfected plants. However, accumulation of N-mRNA in infected plants indicates that transcription is stimulated by TMV infection (up to 38-fold in locally infected leaves and up to 165-fold in upper, noninoculated leaves). Potato virus Y infection did not result in accumulation of N-mRNA, indicating a specific TMV-related phenomenon. The possible uncoupling of viral restriction from necrosis is discussed.
The Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Robert H. Smith Institute for Plant Science and Genetics, Virus Laboratory, Rehovot 76100, Israel.
Michal
M
Levy
Orit
O
Edelbaum
Ilan
I
Sela
D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000821:virology; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014026:Nicotiana / Q000821:virology*; D014027:Tobacco Mosaic Virus / Q000235:genetics*
D004279:DNA, Viral; D012367:RNA, Viral