The Complete Plastome of 'Mejhoul' Date Palm: Genomic Markers and Varietal Identification

Next-generation sequencing technology was employed to read and assemble the complete plastid genome of the 'Mejhoul' date palm cultivar (Phoenix dactylifera L.). The genome consisted of 158,436 base pairs (bp) with a GC content of 37.24%, and it included 95 protein-coding genes, 44 tRNA genes, and eight rRNA genes. The plastome of five 'Mejhoul' genotypes from Jordan was compared with three genotypes from the USA, Morocco, and the UAE. It revealed 91 single-nucleotide polymorphisms (SNPs) and 23 insertions-deletions (InDels); the majority of them (62%) were located in intergenic regions, while the remaining variants were located in intragenic regions, including tRNA and rRNA genes. When the plastomes of all eight 'Mejhoul' genotypes were aligned, along with major cultivars 'Barhee' and 'Khalas', 24 SNPs and 23 InDels could be found. This would enable the development of a cultivar-specific fingerprint test for authentication. The phylogenetic tree was constructed using seventeen date palm cultivars. The phylogenetic analysis places 'Mejhoul' as a lineage derived within Clade I rather than as an early-diverging cultivar, suggesting it shares a more recent common ancestor with 'Deglet Noor' and 'Barhee'.