Transformation of two potato cultivars 'Spunta' and 'Claustar' (Solanum tuberosum) with lettuce mosaic virus coat protein gene and heterologous immunity to potato virus Y

The coat protein (CP) gene of the lettuce mosaic potyvirus (LMV) was introduced into two potato cultivars-Spunta and Claustar-via Agrobacterium tumefaciens-mediated transformation. Gene expression was verified by Southern, Northern and Western blot. The regenerated plants have been tested for resistance against potato virus Y (PVY-0) in greenhouse. We observed an immune phenotype in four transgenic lines expressing the CP-LMV protein at different delectable levels. However, in two other transgenic plant lines, symptoms were developed at a frequency of 25 and 60% with a delay in their appearance. Transgene transcripts of the CP-LMV gene were detected by Northern blot in these two lines, but the protein could not be detected by Western blot. The correlation between the presence of the CP protein at a detectable level and the expression of an immune phenotype is discussed. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.