Partial resistance of transgenic peas to alfalfa mosaic virus under greenhouse and field conditions

Transformed pea (Pisum sativum L.) lines were produced with two chimeric ge ne constructs encoding the coat protein (CP) of alfalfa mosaic virus (AMV) strain NZ1. To determine whether transformed lines have improved AMV resist ance, progeny of independently derived transgenic lines were tested in the greenhouse and five lines with improved virus resistance were identified. R esistance was observed only in individual plants that accumulated detectabl e CP product from the transgene, suggesting that resistance is CP mediated. Plants that accumulated detectable amounts of transgene CP product yet wer e susceptible to AMV were found among the progeny of most lines, indicating that these lines are only partially resistant to the challenging AMV strai ns, 425 and NZ1(Lincoln). A field test was conducted with the progeny of fo ur independently derived transgenic tines. To test for improved virus resis tance under field conditions, plots of transgenic lines and nontransgenic c ontrols were inoculated with two AMV strains, NZ1(Lincoln) and NZ34. Analys is of disease severity in seedlings in inoculated plots confirmed that part ial virus resistance can be produced by genetically modifying peas with AMV CP sequences.