Fucosyltransferases are a group of enzymes that catalyse the transfer of l-fucose from a donor substrate to an acceptor molecule. Silybum marianum is also called ‘milk thistle’ due to its characteristic flower shape. It produces two major flavonoids: silymarin and silybin. The plant and its major secondary metabolites are used for treatment/recovery after chronic liver disease, liver rehabilitation after hepatitis and treatment of gallbladder disease. These compounds also act as antioxidants for scavenging free radicals and inhibiting lipid peroxidation. We identified two peptide motifs (YYEAYLSHADEK and TTPDPSCGR designated as motif 1 and motif 2, respectively) of a fucosyltransferase derived from S. marianum that are highly conserved in its counterparts across the plant species and sources. The nature and properties of the motifs are discussed in terms of their putative participation in catalysis and enzyme/active site conformation.

Amplified fragment length polymorphism analysis was employed to investigate the population structure of 32 Iranian Silybum marianum populations along with two commercial varieties. A total of 415 polymorphic marker loci were produced by 27 primer combinations with an average of 15.37 markers per combination. Polymorphic information content ranged from 0.24 to 0.44 with an average of 0.35 per primer combination, and marker index was in the range of 2.56–9.50 with an average of 5.37. The average Nei's genetic diversity (HE) and Shannon's diversity index (I) were 0.201 and 0.296, respectively. The coefficient of differentiation among populations (GST) was 0.44, indicating that 44% of the total molecular diversity resulted from differences between populations. We identified three major groups based on cluster analysis and principal coordinate analysis, which were mostly in concordance with the geographical grouping of the populations. The molecular diversity estimate could be useful for selecting appropriate populations to improve S. marianum through conventional and molecular breeding.