[Transcriptome-based gene mining and bioinformatics analysis of p-hydroxybenzoate geranyltransferase genes in Arnebia...

The p-hydroxybenzoate geranyltransferases(PGT) play an important role in the biosynthesis pathways of shikonin derivatives. Six PGTs were obtained from transcriptome datebase of Arnebia euchroma by using bioinformatics methods and the proteins＇physiochemical properties they encoded were predicted. The result of protein domain prediction showed all of the six protein sequences contained the conserved domain of Ubia prenyltransferase family and possessed the motif NDxxDxxxD for prenyldiphosphate binding and a GX(K/Y)STAL sequence for putative aromatic ring binding. The phylogenetic tree showed that PGT and p-hydroxybenzoate polyprenyltransferase(PPT) belonged to two different clades. The results of gene expression analyses showed that the expression levels in the red shikonin-proficient line and the overground part of A. euchroma that could produce shikonin derivatives was much higher than the white shikonin-deficient line and the underground part, which suggested a positive correlation between the expression levels of PGT genes and shikonin production. This study aims to lay a foudation for further understanding of the function and enzymatic properties of PGT and provide a basis for the biosynthesis pathways and metabolic regulation of shikonin derivatives.