Isolation and molecular characterization of three acyl carrier protein genes in olive (Olea europaea L.)

In plants, acyl carrier proteins (ACPs) are generally encoded by multigene families. We have isolated from olive (Olea europaea L.) six ACP cDNAs, and their corresponding genomic sequences, coding for plastidial ACP isoforms. Three different OeACP loci have been identified, each with a pair of alleles. The transcript abundance of OeACP1 in olive tissues is extremely low in comparison to the other OeACP genes. The OeACP2 and OeACP3 transcripts are easily detected in all tissues. OeACP2 is the most abundant in fruit and leaf tissues. In addition, OeACP3 seems to be highly expressed in flower. At the protein level, ACP is predominantly found in fruit, and to a minor extent, in flowers and leaves. The analysis of the expression pattern of ACP genes during fruit development has revealed a good correlation between the level of transcripts and the amount of protein, which indicates that ACP expression in olive pulp is mainly regulated at the transcriptional level. We suggest that OeACP2 and OeACP3 proteins are involved in the synthesis of fatty acids for the accumulation of triacylglycerols in olive fruits.