Chloroplast Genome

The genome 0f Albizia kalkora has a circular structure of 176,158 bp, containing a large single-copy (LSC) region of 91,521bp, a small copy (SSC) region of 5,237 bp, and two inverted repeat (IR) regions of 39,700 bp by each. It encodes a total of 109 unique genes, including 76 protein-coding genes, 4 ribosomal RNA genes, and 29 transfer RNA genes. The GC content of A. kalkora chloroplast genome is 35.45%. The genetic distance analysis of the intergenic spacer regions for A. kalkora, A. odoratissima and A. bracteate shows four intergenic spacer regions with very high K2p values, namely, regions of ccsA-ndhD, matK-rps16, rps11-rpl36 and rps3-rps19. In addition, we designed ten pairs of primers for the identification of three Albizia species. The IR boundaries analysis of three cp genomes of Albizia species shows that they have identical boundary structure. The phylogenetic analysis showed Albizia was most closely related to Samanea. Selective pressure analysis shows ndhB and rpoC2 genes having undergone positive selection in the branch composed of Albizia species.