Abstract：Abstract: EIN3(ethylene insensitive 3) in Arabidopsis thaliana is a novel nuclear-localized protein, which is thought to serve as a transcription factor in response to ethylene signal. The cDNA of homologous genes of A.thaliana EIN3 was obtained from tomato (Lycopersicon esculentum ) fruit by RT-PCR amplification and cDNA library screening，termed Le-EIL . The cDNA clone contained an open reading frame of 1 845 bp , encoding a sequence of 615 amino acid. Primary sequence analysis indicated that it exhibited 79% sequence similarity to tobacco(Nicotiana tabacum ?雪 TEIL and the sequence similarity of this clone to A.thaliana EIN3, EIL1,EIL2 and EIL3 was 59%、56%、52%、and 46% respectively. Its expression patterns in both wild type tomato and antisense-ACS transgenic tomato fruit development showed that the expression of Le-EIL gene highly relatived to ripening and ethylene synthesis. In wild type tomato fruit, the expression of Le-EIL gene increased as the fruits got ripening, and reached its peak level at turning and pink stage, then decreased. In antisense-ACS transgenic tomato fruit, the expression of Le-EIL was weak at 60 d fruit past anthesis but disappeared at the other ripening stages.
