Tomato cDNA was labeled with [[α-³²P]dCTP by the random primer method (Pharmacia) and used as probe. Hybridization was carried out at 65 ํc over night in prehybridization mixture with 5% dextran sulfate. Filters were washed five times (30 min each) at 65 ํc in 2x SSc and 0.5% SDS.