Genetic diversity of Citrullus colocynthis populations using phytochemical analysis and SCoT marker variations

Citrullus colocynthis L. Schard (bitter melon) is a drought-resistant medicinal plant growing in Egypt and many other countries in the arid environments of the World. In Egypt, it is abundant in several locations in Egypt's Eastern Desert, extending from the Nile River eastward to the Red Sea, particularly in the Kosseir region on the Red Sea coast. It has a wide range of applications in traditional medicine due to its anti-inflammatory, antibacterial, antioxidant, and anesthetic features. In this study, the genetic diversity was explored using chemical analysis of the secondary metabolites in seed extract in 15 populations from different sites in the Eastern Desert of Egypt to correlate the chemical variation with genetic differences among populations as revealed by DNA fingerprinting using the Start Codon Targeted (SCoT) markers. A total of 81 chemical compounds were identified from the 15 populations. Retention time, peak area percentage, molecular weight, and chemical formula were determined for each compound. Ten SCoT primers produced 137 bands in the 15 populations of these; 85 bands were polymorphic, 50 were monomorphic, and two bands were unique to a single population. Populations located in the southern part of the Eastern Desert have similar levels of phytochemical and genetic diversity and are differentiated from populations in the northern part. On the other hand, populations in the middle part show a small resemblance to other populations in the north and south, indicating an impact of the ecology on the genetic differentiation and the chemical composition of the secondary metabolites in C. colocynthis.