Gene clustering and co-expression analysis for the identification of putative transcription factors associated with the genes of secondary metabolic pathways in Plantago ovata Forsk. and its wild allies

Genus Plantago of Plantaginaceae family is bestowed with a repertoire of structurally diverse secondary metabolites that have not only been used as therapeutics but also effect the plant physiology by conferring adaptive advantages under stress. Assuming that domestication process in plants has influenced their secondary metabolites, we performed a comparative transcriptome of wild and cultivated species of Plantago to analyze the variation in the expression of genes related to secondary metabolite pathways. GO and KEGG analysis of DEGs in wild species showed their enrichment in abiotic stresses, oxidation–reduction and secondary metabolite related pathways. Overall, we found upregulation of genes of carotenoid, flavonoid and phenylpropanoid, isoprenoid, terpenoid and alkaloid pathways in wild species of Plantago in particular, P. lanceolata while mucilage pathway-related genes showed higher expression in P. ovata. Moreover, transcriptome data presented putative transcription factors associated with terpenoids, carotenoid and phenylpropanoid biosynthetic pathways which were also identified using co-expression analysis of cluster 9 (secondary metabolite enriched gene cluster). Taken together, the genomic resource obtained from the present study form a valuable repository of genetic information for elucidating and exploring the secondary metabolic circuitry of Plantagos. Further, information on the regulatory aspects of genes related to secondary metabolites, shall aid in the enhanced production of valuable metabolites in these plants.