The dual role of the potyvirus P3 protein of Turnip mosaic virus as a symptom and avirulence determinant in brassicas.
Two isolates of the potyvirus Turnip mosaic virus (TuMV), UK 1 and CDN 1, differ both in their general symptoms on the susceptible propagation host Brassica juncea and in their ability to infect B. napus lines possessing a variety of dominant resistance genes. The isolate CDN 1 produces a more extreme mosaic in infected brassica leaves than UK 1 and is able to overcome the resistance genes TuRB01, TuRB04, and TuRB05. The resistance gene TuRB03, in the B. napus line 22S, is effective against CDN 1 but not UK 1. The nucleic acid sequences of the UK 1 and CDN 1 isolates were 90% identical. The C-terminal half of the P3 protein was identified as being responsible for the differences in symptoms in B. juncea. A single amino acid in the P3 protein was found to be the avirulence determinant for TuRB03. Previous work already has identified the P3 as an avirulence determinant for TuRB04. Our results increase the understanding of the basis of plant-virus recognition, show the importance of the potyviral P3 gene as a symptom determinant, and provide a role in planta for the poorly understood P3 protein in a normal infection cycle.
Jenner
Carol E
CE
Horticulture Research International, Wellesbourne, Warwick, CV35 9EF, UK. carol.jenner@hri.ac.uk
Wang
Xiaowu
X
Tomimura
Kenta
K
Ohshima
Kazusato
K
Ponz
Fernando
F
Walsh
John A
JA
D001483:Base Sequence; D001937:Brassica / Q000821:virology*; D017931:DNA Primers; D008969:Molecular Sequence Data; D009029:Mosaic Viruses / Q000235:genetics / Q000472:pathogenicity*; D014764:Viral Proteins / Q000502:physiology*; D014774:Virulence
D017931:DNA Primers; D014764:Viral Proteins