CHLOROPLAST GENOME AND PHYLOGENETIC ANALYSIS OF KATMON (Dillenia philippinensis Rolfe), A PHILIPPINE ENDEMIC FRUIT

BackgroundKatmon (Dillenia philippinensis Rolfe) is a Philippine endemic fruit species with a relatively well-studied biochemical profile but poor genomic characterization. Studies involving the chloroplast genome can provide valuable insights into its evolution and support conservation efforts. MethodsThe complete chloroplast genome of D. philippinensis was sequenced using Illumina NovaSeqX. Reads were quality-checked, assembled with GetOrganelle, and annotated using CPGAVAS2 and GeSeq. Simple sequence repeats, codon usage, and inverted repeat boundaries were analyzed. Phylogenetic relationships were inferred using concatenated rbcL and matK sequences via maximum likelihood analysis. ResultThe chloroplast genome was 161,591 bp with a GC content of 36.3%. It exhibited the typical quadripartite structure, consisting of a large single-copy region (89,411 bp), a small single-copy region (19,208 bp), and a pair of inverted repeats (26,486 bp each). A total of 113 unique genes were identified, comprising 79 protein-coding, 30 tRNA, and four rRNA genes. Fifty-four SSRs, primarily A/T mononucleotide repeats, and 53,863 codons were observed. Phylogenetic analysis placed D. philippinensis as the closest relative to D. suffroticosa and the most distantly related to D. ovata. The complete chloroplast genome of D. philippinensis provides a valuable resource for phylogenetic studies, germplasm characterization, and future breeding and conservation programs.