9.A.76. The Omega3 Fatty Acid Desaturase 3/Putative Transporter (FAD3) Family
FAD3-like proteins have been known to be fatty acid desaturases for many years (Pugh and Kates 1979). Oilseed crop oils contain a variety of unsaturated fatty acids that are synthesized and regulated by fatty acid desaturases (FADs). Soltani Gishini et al. 2019 examined 14 FAD3 (omega3 desaturase) protein sequences from oilseeds indicating a close relationship between Brassica napus and Camelina sativa, as well as between Salvia hispanica and Perilla frutescens FAD3s, due to a high similarity in codon preferences in codon usage clusters and the phylogenetic tree. The cis-acting elements showed that the seed-specific promoter region of BnFAD3 contains the critical conserved boxes (HSE and ABRE), which are involved in responsiveness to heat stress and abscisic acid. These boxes may increase cold acclimation as well as tolerance to drought and high salinity. Omega(omega)3 desaturases contain a Skn-1 motif which is a cis-acting regulatory element required for endosperm development. It was found that BnFAD3 is a transmembrane protein, probably wit h6 TMSs, that can convert omega6 to omega3 fatty acids and may simultaneously act as a potassium ion channel in the ER.