Partial coding sequence identification, gene expression analysis, and content of anticancer phenolic compounds in Sonchus arvensis L. under drought stress conditions

Field sowthistle, a plant in the Asteraceae family, contains high levels of chlorogenic and chicoric acids, which have anticancer properties. In the current investigation, the expression of genes responsible for chlorogenic acid biosynthesis was studied in S. arvensis in drought stress conditions. The following genes were investigated: phenylalanine ammonia-lyase (PAL), cinnamate 4 hydroxylase (C4H), 4-hydroxycinnamoyl CoA ligase (4CL), hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase (HCT), hydroxycinnamoyl CoA quinate hydroxycinnamoyl transferase (HQT) and p-coumaroyl ester 3'-hydroxylase (C3'H). As part of a research study, the levels of several anticancer compounds and their correlation with the transcriptional activity of the surveyed genes were investigated under drought stress conditions. The study also involved the identification and submission of the partial coding sequences of the C4H, HCT, C3'H, and actin genes in S. arvensis to the GenBank database. The plants’ middle leaves exposed to 50% field capacity (FC) exhibited the highest expression of all genes. The highest amount of chicoric, chlorogenic, and 2,5 dihydroxybenzoic (2,5 DHB) acids was observed in the middle leaves under 50% FC. In contrast, the highest content of gallic acid and catechin was found in the lower leaves at 75% FC. A strong association between HQT expression and chlorogenic acid content proposed the HQT-dependent metabolic pathway as the primary route for its production in S. arvensis. Furthermore, the consistency between the patterns of gene expression and the levels of compounds found in the middle leaves at 50% FC, except for catechin, showed that the production of chlorogenic acid in S. arvensis could potentially be enhanced by stimulating the expression of the genes that are responsible for its biosynthesis.