Cloning and preliminary characterisation of the promoter region of the 1-aminocyclopropane-1-carboxylate synthase gene.

The 1-aminocyclopropane-1-carboxylate synthase (ACS) is a key enzyme for ethylene production during apple fruit ripening. It is reported that an allele of this gene (ACS1-2), with a short interspersed nuclear element (SINE) insertion in the promoter region, has very low transcription activity compared with the ACS1-1 allele. We isolated the two allele sequences by screening an apple BAC library of cultivar 'Florina' and their sequences were preliminarly characterized by bioinformatic analysis. As expected the major differences were in the promoter region. Seven different 5'-deletion constructs were designed based upon these differences in order to investigate their possible role in gene activity. The promoter fragments were fused to the GUSPlus ™ reporter gene of a modified pCAMBIA 0305.1 vector. These constructs will be transferred to Agrobacterium tumefaciens EHA105 strain and used for GUS transient expression tests into apple leaves and fruits by agroinfiltration.