Isolation and characterization of acid invertase cDNA clone in hot pepper (Capsicum annuum L.) fruits

An acid invertase (EC 3.2.1.26.) cDNA clone,CaAIV-18, was isolated from the red pericarp cDNA library of the hot pepper (Capsicum annuum L.) fruit. TheCaAIV-18 clone has 2223 nucleotides and one open reading frame encoding 641 amino acid residues. Analysis of deduced amino acid sequences reveals thatCaAIV-18 has a 24-amino acid transmembrane anchor region in its N-terminal, implying acid invertase in hot pepper may be localized in the membrane and not in the cytosol. This clone showed high homology to tomato acid invertase,Aiv1, in nucleotide and deduced amino acid sequences. In the Southern blot analysis, this clone proved to exist as single or low copy numbers on the genome of hot pepper. The clones had two well-conserved regions which appears in acid invertase of other plant species (eg. tomato,Arabidopsis, etc.) and yeasts. During fruit development,CaAIV-18 was expressed preferentially in the ripe red stage.