The cyv-2 resistance to Clover yellow vein virus in pea is controlled by the eukaryotic initiation factor 4E

The same mutant allele of eukaryotic initiation factor 4E (eIF4E) that confers resistance to Pea seed-borne mosaic virus (sbm-1) and the white lupine strain of Bean yellow mosaic virus (wlv) also confers resistance to Clover yellow vein virus (ClYVV) in pea. The eIF4E genes from several pea lines were isolated and sequenced. Analysis of the eIF4E amino acid sequences from several resistant lines revealed that some lines, including PI 378159, have the same sequence as reported for sbm-1 and wlv. When eIF4E from a susceptible pea line was expressed from a ClYVV vector after mechanical inoculation of resistant PI 378159, the virus caused systemic infection, similar to its effects in susceptible line PI 250438. The resistance to ClYVV in line PI 378159 was characterized through a cross with PI 193835, which reportedly carries cyv-2. Mechanical inoculation of the F1 progeny with ClYVV resulted in no infection, indicating that the resistance gene in PI 378159 is identical to cyv-2 in PI 193835. Furthermore, particle bombardment of pea line PI 193835 with infectious cDNA of ClYVV (pClYVV/C3-S65T) resulted in the same resistance mode as that described for PI 378159. These results demonstrate that the resistance to ClYVV conferred by cyv-2 is mediated by eIF4E and that cyv-2 is identical to sbm-1 and wlv.