A 1450 base pair (bp) cDNA encoding an acyl-ACP thioesterase was isolated from a developing mesocarp cDNA library. The cDNA sequence corresponding to the mature protein is 66% identical to Cuphea hookeriana Ch FatB1, and 35% identical to Garcinia mangostana Garm FatA1, indicating that this clone belongs to the FatB type of acyl-ACP thioesterases. Although the sequence showed the cDNA to be incomplete, lacking the 5′ untranslated region and most of the transit peptide, the mature protein is intact and will be expressed in Escherichia coli to investigate the substrate specificity of the acyl-ACP thioesterase.