The genomic regulation of nutritional quality and secondary metabolism in Crithmum maritimum in response to stress and elicitors

Abstract

Sea fennel, known in the scientific community as Crithmum maritimum, is a perennial aromatic halophyte of the Apiaceae family usually found in coastal areas. It has been described as an extremophile due to its resistance in drought and salinity conditions, as well as its presence in sandy terrains. The plant apart from its sustenance in harsh conditions is also a source of secondary metabolites, synthesized to protect it from hazards, some of which are beneficial to human diet. Among them are chlorogenic acid, coumaric acid, ferulic acid, epicatechin and vitamin C. Jasmonates are a category of plant elicitors with hormonal function that can protect the plant from biotic and abiotic hazards and enhance its commercial value. The experiment for this thesis was conducted in the American Farm School of Thessaloniki, using a local variety of sea fennel, into which various treatments of salinity (100 or 200 mM), jasmonic acid spraying (1 mM), fertilizer (11-15-15) and combinations of all the above were applied. Leaves of each sample were freeze-dried and grinded. The RNeasy protocol was used to yield its RNA, which was then transcribed into cDNA. Finally, qPCR was conducted using primers designed from the sequences of the close relative species of carrot, to monitor the expression of seven genes, involved in the production of antioxidants. In addition to that, the antioxidant capacity was recorded using a DPPH solution and the total phenolic content was measured with the Folin Ciocalteu method. This experiment successfully amplified for the first time the genes CHS, FED, GDP, IPI, LIS, PAL and SQH inside sea fennel’s genome, with PAL being the most highly expressed. Treatment with jasmonic acid was found to be very beneficial for their expression, while salt treatments resulted in lower expression. Both tests of antioxidant capacity and total phenolic content, yielded high results and a possible correlation between the genes FED, LIS and the antioxidant capacity.