Molecular cloning and characterization of ETHYLENE OVERPRODUCER 1-LIKE 1 gene, LeEOL1, from tomato (Lycopersicon esculentum Mill.) fruit.

Recently, ETHYLENE OVERPRODUCER 1 (ETO1) had been cloned and identified as a negative post-transcriptional regulator in the ethylene biosynthesis in Arabidopsis. However, little was known about the role of ETO1 in other species, especially in tomato, which was an ideal model for studying the biosynthesis of ethylene during tomato fruit ripening. In this study, a tomato ETHYLENE OVERPRODUCER 1-LIKE 1 (LeEOL1) was cloned. The LeEOL1 cDNA was 3,515 bp long and carried an ORF that putatively encoded a polypeptide of 886 amino acids with a predicted molecular mass of 95 kDa. It shared 74% identity in amino acid sequence with Arabidopsis EOL1 and had one BTB (Broad-complex, Tramtrack, Bric-à-brac) domain and two TPR (tetratricopeptide repeat) domains, which were also conserved domains in AtEOL1. RT-PCR analysis of the temporal expression of LeEOL1 showed that its transcript decreased companied with increase of ethylene production in tomato ripening. The level of LeEOL1 transcripts in wild type tomato fruit at mature green stage did not distinctively change when treated with exogenous ethylene.