Kenji S. Nakahara,
Jun Shao, and
Pathogen-Plant Interactions Group, Plant Breeding Science, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
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Accepted 12 July 2010.
Two recessive genes (cyv1 and cyv2) are known to confer resistance against Clover yellow vein virus (ClYVV) in pea. cyv2 has recently been revealed to encode eukaryotic translation initiation factor 4E (eIF4E) and is the same allele as sbm1 and wlm against other potyviruses. Although mechanical inoculation with crude sap is rarely able to cause infection of a cyv2 pea, biolistic inoculation of the infectious ClYVV cDNA clone does. At the infection foci, the breaking virus frequently emerges, resulting in systemic infection. Here, a derived cleaved-amplified polymorphic sequence analysis showed that the breakings were associated with a single nonsynonymous mutation on the ClYVV genome, corresponding to an amino-acid substitution at position 24 (isoleucine to valine) on the P1 cistron. ClYVV with the point mutation was able to break the resistance. This is a first report demonstrating that P1 is involved in eIF4E-mediated recessive resistance.
© 2010 The American Phytopathological Society