These unsaturated FAs are synthesiz

These unsaturated FAs are synthesized by the sequential insertion of double bonds into palmitic and stearic acid derivatives. The first of these desaturation events is carried out in plastids and chloroplasts by the soluble stearoyl-ACP desaturase. Subsequently, to synthesize the 16:2/18:2 and 16:3/18:3 FAs that are essential for plant membranes, a second and a third double bond are introduced by Δ12 and ω-3 membrane-bound desaturases,respectively. These desaturases can be found in both the plastid/chloroplast (the so called “prokaryotic pathway”) and in the endoplasmic reticulum (“eukaryotic pathway”). The first of these pathways is used predominantly in photosynthetically active tissues, whereas the microsomal pathway predominates in non-green tissues and developing seeds [6]