Journal of Plant Pathology (2002) 84, p. 189a (Parrella et al.)

G. Parrella and C. Vovlas (2002)
Characterization of a ToMV strain isolated from a resistant tomato lines
Journal of Plant Pathology 84 (3), 189-189
IX Meeting, Italian Society for Plant Pathology
Abstract: A new resistance breaking strain of Tomato mosaic virus (ToMV-MK) able to overcome the Tm-2a gene is described. ToMV-MK, isolated during 2001 in Apulia (southern Italy) from the tomato variety Naxos, was able to cause severe systemic symptoms in plants carrying Tm-2a with Moneymaker genetic background. On the contrary, plants with Ailsa Craig or Vendor genetic backgrounds, carrying Tm-2a gene, were not affected. Tm-1 gene controlled efficiently ToMV-MK in plants with the three genetic backgrounds considered. The sequence of the 30-kDa movement protein of ToMV-MK was determined and compared with those from other resistance-breaking strains but no substitutions in common were found. Three out of five substitutions found in ToMV-MK movement protein occurred in the carboxyterminal domain of the protein. One of these substitutions, Asp->Tyr₂₄₀, was apparently associated with changes of the 30-kDa secondary structure in a surface-accessible area including the last 30 aminoacids of the C-terminus domain. The results suggest that changes in the C-terminus secondary structure of the 30-kDa movement protein might alter the recognition event between the 30-kDa and the Tm-2a gene product, conferring to ToMV-MK the ability to overcome the resistance. In Tm-2a tomato lines with Vendor and Ailsa Craig genetic backgrounds, probably the presence of other factors, alone or in addition to Tm-2a, increase the efficiency of resistance to ToMV-MK.
Database assignments for author(s): Giuseppe Parrella

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tomato mosaic virus	Tomato (Solanum lycopersicum)	Italy