title: Identification and characterization of a locus (RTM1) that restricts long-distance movement of tobacco etch virus in Arabidopsis thaliana.
abstract: Screens of Arabidopsis thaliana for susceptibility to tobacco etch virus (TEV) revealed that each of 10 ecotypes were able to support genome replication and cell-to-cell movement in inoculated leaves. However, only four ecotypes, including C24 and La-er, supported complete infections in which TEV was able to replicate and move from cell to cell and long distances through the vasculature. The rates of cell-to-cell movement of a reporter-tagged TEV strain (TEV-GUS) in inoculated leaves of C24 and Columbia (Col-3) were similar, and infection foci continued to expand in both ecotypes through 10 days post-inoculation. No visible or microscopic hypersensitive or cell death responses were evident in inoculated leaves of Col-3 plants. Infection of neither C24 nor Col-3 plants with TEV-GUS resulted in induction of PR-1a gene expression, which is normally associated with active defence responses and systemic acquired resistance. The genetic basis for the restriction of long-distance movement of TEV-GUS in Columbia was investigated using C24 x Col-3 crosses and backcrosses and using La-er x Col-0 recombinant inbred lines. A dominant locus conditioning the restricted TEV infection phenotype was identified on chromosome 1 between markers ATEAT1 and NCC1 at approximately 14 cM in both genetic analyses. This locus was designated RTM1 (restricted TEV movement 1). It is proposed that RTM1 mediates a restriction of long-distance movement through a mechanism that differs substantially from those conditioned by the dominant resistance genes normally associated with gene-for-gene interactions.
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman 99164-6340, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Mahajan
authors.forename: S T
authors.initials: ST
authors.lastname: Chisholm
authors.forename: S A
authors.initials: SA
authors.lastname: Whitham
authors.forename: J C
authors.initials: JC
authors.lastname: Carrington
mesh_terms: D017360:Arabidopsis / Q000821:virology*; D001692:Biological Transport; D016923:Cell Death; D002874:Chromosome Mapping; D005966:Glucuronidase / Q000378:metabolism; D007113:Immunity, Innate; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics / Q000821:virology*; D010947:Plants, Toxic; D019176:Potyviridae / Q000201:enzymology / Q000235:genetics* / Q000472:pathogenicity*; D014026:Nicotiana / Q000821:virology*
chemical_list: D005966:Glucuronidase