Cloning and characterization of two acyl-ACP thioesterases from Koelreuteria paniculate

17th Euro Fed Lipid Congress 20-23 October 2019, Seville, Spain
cis-11-Eicosenoic acid (20:1¿¿9, EA) is a monounsaturated fatty acid that is contained in a variety of plant oils. Some of these oils have a special interest for the industry due to they could be used in engine lubricant oil, pharmaceutical compounds and cosmetics. Approximately 48% of the fatty acid composition in Koelreuteria paniculate oil correspond to EA. The specificity of the acyl-ACP thioesterases plays an important role in controlling the fatty acid composition of seed oil. In order to determine the mechanisms involved in the biosynthesis of fatty acids in Koelreuteria paniculate seeds, we isolated, cloned and sequenced two cDNA coding for acyl-ACP thioesterases, KpFatA1 and KpFatB1. Both of them were heterologously expressed in Escherichia coli and characterized with different acyl-ACP substrates. Whereas KpFatA1 encodes a functional thioesterase with preference for monounsaturated acyl-ACPs (18:1-ACP), the KpFatB1 thioesterase showed higher efficiencies (kcat/KM) for saturated acyl-ACPs (18:0-ACP and 16:0-ACP) than KpFatA1. Lipid composition of tobacco leaves agroinfiltered with KpFatA1 and KpFatB1 for their transient expression was analysed. The results showed changes in the fatty acid composition of leaves overexpressing KpFats respect to non-agroinfiltered ones.