Objective  The ketoacyl-coenzyme A synthase (KCAS) gene relating to responses of Primulina spinulosa to drought and other stresses was studied based on the transcriptome sequencing.

  Method  Total RNA of the gene was extracted by the improved Trizol method for sequencing with the established database. Physicochemical properties of the open reading frame (ORF), coding amino acids, and proteins of the gene were analyzed by DNAman, Finder, TMPRED, SWISS-MODEL, NetPhos 2.0, and SignaIP4.1. The phylogenetic tree was constructed accordingly.

  Results  The full length of the KCAS gene was determined to be 1 935 bp (GenBank login number MH543314), ORF 1 599 bp, encoding 532 amino acids, molecular weight 59.82 kDa, and theoretical pI 9.16. It was a hydrophilic protein with 7 transmembrane regions, 30 possible phosphorylation sites, and one conservative domain similar to that of the chalcone synthase family. The homology between it and Dorcoceras hygrometricum (KZV788) was as high as 92%, and they were in a same phylogenetic tree.

  Conclusion  The KCAS gene was postulated to relate to the leaf wax synthesis of P. spinosa and played an important role in drought resistance and biological response to stresses of the plant.