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.
Levy
Michal
M
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.
Edelbaum
Orit
O
Sela
Ilan
I
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