Phylogenetic Diversity of Allspice (Pimenta Dioica) Collections from Tanzania Using Chloroplast (Cp) Rbcl Gene

Abstract

This study aims to investigates the phylogenetic relationship between various collection of Allspice (Pimenta dioica) from Tanzania using cprbcL gene as a DNA barcode. Allspice is an important plant species valued for its economic, medicinal, and cultural uses. The morphological similarities between Allspice and other trees in the Myrtaceae family have led to misidentification, making it crucial to use DNA barcoding to study their evolution history. The molecular phylogeny was conducted using DNA extraction, PCR amplification, and sequencing of the rbcL gene, followed by phylogenetic analysis. The genomic DNA was extract using the CTAB method and the rbcL gene amplified with a forward primer 5’-ATGTCACCACAAACAGAGACTAAAGC-3’ and a reverse primer 5’-GTAAAATCAAGTCCACCRCG-3’. Phylogenetic analysis of Allspice rbcL gene was performed by multiple sequence alignment using MUSCLE 5.1 embedded in Geneious Prime software version 2023.0.1 phylogenetic tree was constructed using the same software. The results showed that DNA specimen amplified at amplicon size of average 560bp with GC content of 44%. BLASTN search resulted into more than 96% similarity to seventeen members of Myrtaceae family namely Eucalyptus torquata (NC_022401), Eucalyptus spathulata (NC_022400), Eucalyptus torquata (KC180794), Eucalyptus spathulata (KC180793), Syzygium polyanthum (OQ355361), Syzygium aromaticum (ON920513), Luma apiculata (KX162972), Eugenia aggregata (OP650216), Eugenia Selloi (MN095411), Myrcianthes pungens (MN095409), Campomanesia xanthocarpa (KY392760), Acca sellowiana (KX289887), Syzygium samarangense (NC_060657), Lophomyrtus bullata (MW214669), Lenwebbia prominens (MW214668), Lenwebbia lasioclade (MW214667), and Syzygium nervosum (NC_053907). In the phylogenetic tree Allspice rbcL gene has a close branch to members of Myrtaceae family. This study concludes that there is high genetic diversity among Allspice collection from Tanzania and between member of the Myrtaceae family. Additionally, this study provides a foundation for future research on the evolutionary history and population genetics of Allspice in Tanzania.