Identification and Molecular Phylogenetic Relationships of Δ12-Fatty Acid Desaturase in Arachis

摘要

On the basis of the conservative sequence of Δ12-fatty acid desaturase, a cDNA encoding the enzyme was isolated from different genotypes of Arachis. The cDNA consisted of 1140 bp and encoded a polypeptide of 379 amino acid resides with a calculated molecular weight of 42 KD. The predicted amino acid sequence had three histidine conservative regions sharing integral-protease specificity. Hydrophobicity analysis showed that the sequence of the encoded amino acids had two hydrophobic structures sharing the characteristics of membrane-anchored protein, which totally crossed the membrane four times. These analyses revealed that the obtained sequence was Δ12-fatty acid desaturase. Phylogenetic-tree analysis demonstrated that the found Δ12-fatty acid desaturase sequences in Arachis was conservative and was highly homogenous to the Δ12-fatty acid desaturase sequences in other species. The present research provided molecular evidence of phylogenetic relationships among the accessions in Arachis.