Palmitoleate (cis-Δ9-16:1) shows numerous health benefits such as increased cell membrane fluidity, reduced
inflammation, protection of the cardiovascular system, and inhibition of
oncogenesis.
Plant oils containing this unusual
fatty acid can also be sustainable feedstocks for producing industrially important and high-demand
1-octene.
Vegetable oils rich in
palmitoleate are the ideal candidates for
biodiesel production. Several wild plants are known that can synthesize high levels of
palmitoleate in seeds. However, low yields and poor agronomic characteristics of these plants limit their commercialization. Metabolic engineering has been developed to create oilseed crops that accumulate high levels of
palmitoleate or other unusual
fatty acids, and significant advances have been made recently in this field, particularly using the model plant Arabidopsis as the host. The engineered targets for enhancing
palmitoleate synthesis include overexpression of Δ9 desaturase from mammals, yeast, fungi, and plants, down-regulating KASII, coexpression of an ACP-Δ9 desaturase in plastids and CoA-Δ9 desaturase in endoplasmic reticulum (ER), and optimizing the metabolic flux into
triacylglycerols (TAGs). This review will mainly describe the recent progress towards producing
palmitoleate in transgenic plants by metabolic engineering along with our current understanding of
palmitoleate biosynthesis and its regulation, as well as highlighting the bottlenecks that require additional investigation by combining lipidomics, transgenics and other "-omics" tools. A brief review of reported health benefits and non-food uses of
palmitoleate will also be covered.